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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
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<html>
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<head>
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<title>Ghostscript and the PostScript language</title>
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<!-- $Id: Language.htm,v 1.98 2005/10/20 19:46:23 ray Exp $ -->
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<!-- Originally: language.txt -->
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<link rel="stylesheet" type="text/css" href="gs.css" title="Ghostscript Style">
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</head>
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<body>
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<!-- [1.1 begin headline] ================================================== -->
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<h1>Ghostscript and the PostScript language</h1>
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<!-- [1.1 end headline] ==================================================== -->
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<!-- [1.2 begin table of contents] ========================================= -->
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<h2>Table of contents</h2>
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<blockquote><ul>
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<li><a href="#Capabilities">Ghostscript's capabilities in relation to PostScript</a>
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<li><a href="#Implementation_limits">Implementation limits</a>
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<ul>
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<li><a href="#Architectural_limits">Architectural limits</a>
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<li><a href="#Typical_memory_limits">Typical memory limits in LanguageLevel 1</a>
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<li><a href="#VM_consumption">Other differences in VM consumption</a>
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</ul>
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<li><a href="#Additional_operators">Additional operators in Ghostscript</a>
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<ul>
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<li><a href="#Graphics_and_text">Graphics and text operators</a>
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<ul>
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<li><a href="#Transparency">Transparency</a>
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<ul>
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<li><a href="#Transparency_graphics_state_operators">Graphics state operators</a>
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<li><a href="#Transparency_rendering_stack_operators">Rendering stack operators</a>
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<li><a href="#Transparency_ImageType">New ImageType</a>
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</ul>
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<li><a href="#Graphics_state">Other graphics state operators</a>
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<li><a href="#Path">Path operators</a>
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<li><a href="#Painting">Painting operators</a>
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<li><a href="#Character">Character operators</a>
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</ul>
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<li><a href="#Other">Other operators</a>
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<ul>
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<li><a href="#Mathematical">Mathematical operators</a>
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<li><a href="#Dictionary">Dictionary operators</a>
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<li><a href="#String">String and name operators</a>
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<li><a href="#Relational">Relational operators</a>
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<li><a href="#File">File operators</a>
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<li><a href="#Virtual_memory">Virtual memory operators</a>
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<li><a href="#Miscellaneous">Miscellaneous operators</a>
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<li><a href="#Device">Device operators</a>
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</ul>
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</ul>
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<li><a href="#Filters">Filters</a>
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<ul>
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<li><a href="#Standard_filters">Standard filters</a>
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<li><a href="#Non_standard_filters">Non-standard filters</a>
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<li><a href="#Unstable_filters">Unstable filters</a>
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</ul>
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<li><a href="#Device_parameters">Device parameters</a>
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<li><a href="#User_parameters">User parameters</a>
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<li><a href="#Miscellaneous_additions">Miscellaneous additions</a>
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<ul>
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<li><a href="#Extended_semantics_of_run">Extended semantics of 'run'</a>
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<li><a href="#DecodingResources">Decoding resources</a>
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<li><a href="#CIDDecodingResources">CIDDecoding resources</a>
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<li><a href="#GlyphNames2Unicode">GlyphNames2Unicode</a>
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<li><a href="#MultipleResourceDirectories">Multiple Resource directories</a>
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</ul>
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</ul></blockquote>
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<!-- [1.2 end table of contents] =========================================== -->
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<!-- [1.3 begin hint] ====================================================== -->
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<p>For other information, see the <a href="Readme.htm">Ghostscript
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overview</a>.
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<!-- [1.3 end hint] ======================================================== -->
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<hr>
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<!-- [1.0 end visible header] ============================================== -->
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<!-- [2.0 begin contents] ================================================== -->
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<h2><a name="Capabilities"></a>Ghostscript's capabilities in relation to PostScript</h2>
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<p>
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The Ghostscript interpreter, except as noted below, is intended to execute
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properly any source program written in the (LanguageLevel 3)
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<b>PostScript</b> language as defined in the <cite>PostScript
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Language Reference, Third Edition</cite> (ISBN 0-201-37922-8) published by
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Addison-Wesley in mid-1999. However, the interpreter is configurable in
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ways that can restrict it to various subsets of this language.
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Specifically, the base interpreter accepts the Level 1 subset of the
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PostScript language, as defined in the first edition of the <cite>PostScript
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Language Reference Manual</cite> (ISBN 0-201-10174-2) Addison-Wesley 1985,
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plus the file system, version 25.0 language, and miscellaneous additions
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listed in sections A.1.6, A.1.7, and A.1.8 of the Second Edition
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respectively, including allowing a string operand for the
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"<b><tt>status</tt></b>" operator. The base interpreter may be configured
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(see the <a href="Make.htm">documentation on building Ghostscript</a> for
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how to configure it) by adding any combination of the following:
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<ul>
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<li>The ability to process PostScript Type 1 fonts. This facility is
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normally included in the interpreter.
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<li>The CMYK color extensions listed in section A.1.4 of the Second Edition
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(including <b><tt>colorimage</tt></b>). These facilities are available
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only if the <b><tt>color</tt></b>, <b><tt>dps</tt></b>, or
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<b><tt>level2</tt></b> feature was selected when Ghostscript was built.
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<li>The Display PostScript extensions listed in section A.1.3 of the Second
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Edition, but excluding the operators listed in section A.1.2. These
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facilities are available only if the <b><tt>dps</tt></b> feature or the
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<b><tt>level2</tt></b> feature was selected when Ghostscript was built.
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<li>The composite font extensions listed in section A.1.5 of the Second
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Edition, and the ability to handle Type 0 fonts. These facilities are
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available only if the <b><tt>compfont</tt></b> feature or the
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<b><tt>level2</tt></b> feature was selected when Ghostscript was built.
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<li>The ability to load TrueType fonts and to handle PostScript Type 42
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(encapsulated TrueType) fonts. These facilities are available only if the
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<b><tt>ttfont</tt></b> feature was selected when Ghostscript was built.
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<li>The PostScript Level 2 "filter" facilities except the
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<b><tt>DCTEncode</tt></b> and <b><tt>DCTDecode</tt></b> filters. These
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facilities are available only if the <b><tt>filter</tt></b>,
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<b><tt>dps</tt></b>, or <b><tt>level2</tt></b> feature was selected when
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Ghostscript was built.
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<li>The PostScript Level 2 <b><tt>DCTEncode</tt></b> and
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<b><tt>DCTDecode</tt></b> filters. These facilities are available only if
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the <b><tt>dct</tt></b> or <b><tt>level2</tt></b> feature was selected when
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Ghostscript was built.
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<li>All the other PostScript Level 2 operators and facilities listed in
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section A.1.1 of the Second Edition and not listed in any of the other
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A.1.n sections. These facilities are available only if the
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<b><tt>level2</tt></b> feature was selected when Ghostscript was built.
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<li>All PostScript LanguageLevel 3 operators and facilities listed in the
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Third Edition, except as noted below. These facilities are available only
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if the <b><tt>psl3</tt></b> feature was selected when Ghostscript was built.
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<li>The ability to recognize DOS EPSF files and process only the PostScript
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part, ignoring bitmap previews or other information. This facility is
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available only if the <b><tt>epsf</tt></b> feature was selected when
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Ghostscript was built.
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</ul>
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<p>
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Ghostscript currently does not implement the following PostScript
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LanguageLevel 3 facilities:
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<ul>
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<li>Native <b><tt>Separation</tt></b> and <b><tt>DeviceN</tt></b> color
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spaces -- the alternate space is always used.
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<li>Settable <b><tt>ProcessColorModel</tt></b> for page devices, except for
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a very few special devices.
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<li><b><tt>IODevice</tt></b>s other than <b><tt>%stdin</tt></b>,
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<b><tt>%stdout</tt></b>, <b><tt>%stderr</tt></b>, <b><tt>%lineedit</tt></b>,
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<b><tt>%statementedit</tt></b>, <b><tt>%os%</tt></b>, and (if configured)
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<b><tt>%pipe%</tt></b> and <b><tt>%disk0%</tt></b> through <b><tt>%disk0%</tt></b>.
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</ul>
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<p>
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Ghostscript can also interpret files in the Portable Document Format (PDF)
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1.3 format defined in the <a
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href="http://partners.adobe.com/asn/developer/PDFS/TN/PLRM.pdf"><em>Portable
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Document Format Reference Manual</em> Version 1.3</a> of March 11, 1999,
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distributed by <a href="http://www.adobe.com/">Adobe Systems
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Incorporated</a>, except as noted below. This facility is available only if
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the <b><tt>pdf</tt></b> feature was selected when Ghostscript was built.
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<p>
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Ghostscript currently does not implement the following PDF 1.3 facilities:
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<ul>
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<li>Native <b><tt>Separation</tt></b> and <b><tt>DeviceN</tt></b> color
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spaces, as noted above for PostScript.
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<li>Native <b><tt>ICCBased</tt></b> color spaces -- these too always use the
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alternate space.
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</ul>
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<p>
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Ghostscript also includes a number of
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<a href="#Additional_operators">additional operators</a> defined below that
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are not in the PostScript language defined by Adobe.
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<hr>
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<h2><a name="Implementation_limits"></a>Implementation limits</h2>
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<p>
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The implementation limits show here correspond to those in Tables B.1 and
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B.2 of the Second and Third Editions, which describe the quantities fully.
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Where Ghostscript's limits are different from those of Adobe's
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implementations (as shown in the Third Edition), Adobe's limits are also
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shown.
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<h3><a name="Architectural_limits"></a>Architectural limits</h3>
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<blockquote><table cellpadding=0 cellspacing=0>
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<tr><th colspan=7 bgcolor="#CCCC00"><hr><font size="+1">Architectural limits (corresponds to Adobe table B.1)</font><hr>
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<tr valign=bottom>
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<th align=left>Quantity
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<td>
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<th align=left>Limit
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<td>
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<th align=left>Type
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<td>
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<th align=left>Adobe
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<tr> <td colspan=7><hr>
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<tr valign=top> <td>integer
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<td>
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<td>32-bit
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<td>
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<td>twos complement integer
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<td>
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<td>
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<tr valign=top> <td>real
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<td>
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<td>single-precision
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<td>
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<td>IEEE float
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<td>
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<td>
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<tr valign=top> <td>array
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<td>
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<td>65535
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<td>
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<td>elements
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<td>
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<td>
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<tr valign=top> <td>dictionary
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<td>
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<td>65534
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<td>
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<td>elements
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<td>
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<td>65535
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<tr valign=top> <td>string
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<td>
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<td>65535
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<td>
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<td>characters
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<td>
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<td>
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<tr valign=top> <td>name
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<td>
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<td>16383
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<td>
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<td>characters
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<td>
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<td>127
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<tr valign=top> <td>filename
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<td>
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<td>128*
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<td>
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<td>characters
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<td>
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<td>
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<tr valign=top> <td><b><tt>save</tt></b> level
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<td>
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<td>none
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<td>
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<td>(capacity of memory)
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<td>
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<td>15
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<tr valign=top> <td><b><tt>gsave</tt></b> level
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<td>
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<td>none
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<td>
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<td>(capacity of memory)
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<td>
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<td>13
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</table></blockquote>
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<p>
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* The limit on the length of a file name is 128 characters if the name
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starts with a %...% IODevice designation, or 124 characters if it does not.
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<h3><a name="Typical_memory_limits"></a>Typical memory limits in LanguageLevel 1</h3>
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<blockquote><table cellpadding=0 cellspacing=0>
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<tr><th colspan=7 bgcolor="#CCCC00"><hr><font size="+1">Memory limits (corresponds to Adobe table B.2)</font><hr>
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<tr valign=bottom>
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<th align=left>Quantity
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<td>
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<th align=left>Limit
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<td>
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<th align=left>Type
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<td>
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<th align=left>Adobe
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<tr> <td colspan=7><hr>
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<tr valign=top> <td><b><tt>userdict</tt></b>
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<td>
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<td>200
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<td>
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<td>
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<td>
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<td>
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<tr valign=top> <td><b><tt>FontDirectory</tt></b>
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<td>
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<td>100
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<td>
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<td>
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<td>
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<td>
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<tr valign=top> <td>operand stack
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<td>
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<td>800
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<td>
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<td>
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<td>
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<td>500
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<tr valign=top> <td>dictionary stack
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<td>
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<td>20
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<td>
|
|
|
334 |
<td>
|
|
|
335 |
<tr valign=top> <td>execution stack
|
|
|
336 |
<td>
|
|
|
337 |
<td>250
|
|
|
338 |
<td>
|
|
|
339 |
<td>
|
|
|
340 |
<tr valign=top> <td>interpreter level
|
|
|
341 |
<td>
|
|
|
342 |
<td>none
|
|
|
343 |
<td>
|
|
|
344 |
<td>(capacity of memory)
|
|
|
345 |
<td>
|
|
|
346 |
<td>10
|
|
|
347 |
<tr valign=top> <td>path
|
|
|
348 |
<td>
|
|
|
349 |
<td>none
|
|
|
350 |
<td>
|
|
|
351 |
<td>(capacity of memory)
|
|
|
352 |
<td>
|
|
|
353 |
<td>1500
|
|
|
354 |
<tr valign=top> <td>dash
|
|
|
355 |
<td>
|
|
|
356 |
<td>11
|
|
|
357 |
<td>
|
|
|
358 |
<td>
|
|
|
359 |
<tr valign=top> <td>VM
|
|
|
360 |
<td>
|
|
|
361 |
<td>none
|
|
|
362 |
<td>
|
|
|
363 |
<td>(capacity of memory)
|
|
|
364 |
<td>
|
|
|
365 |
<td>240000
|
|
|
366 |
<tr valign=top> <td>file
|
|
|
367 |
<td>
|
|
|
368 |
<td>none
|
|
|
369 |
<td>
|
|
|
370 |
<td>(determined by operating system)
|
|
|
371 |
<td>
|
|
|
372 |
<td>6
|
|
|
373 |
<tr valign=top> <td>image
|
|
|
374 |
<td>
|
|
|
375 |
<td>65535
|
|
|
376 |
<td>
|
|
|
377 |
<td>values (samples × components)<br>for1-, 2-, 4-, or 8-bit samples
|
|
|
378 |
<td>
|
|
|
379 |
<td>3300
|
|
|
380 |
<tr valign=top> <td>
|
|
|
381 |
<td>
|
|
|
382 |
<td>32767
|
|
|
383 |
<td>
|
|
|
384 |
<td>values for 12-bit samples
|
|
|
385 |
<td>
|
|
|
386 |
<td>3300
|
|
|
387 |
</table></blockquote>
|
|
|
388 |
|
|
|
389 |
<h3><a name="VM_consumption"></a>Other differences in VM consumption</h3>
|
|
|
390 |
|
|
|
391 |
<p>
|
|
|
392 |
Packed array elements occupy either 2 bytes or 8 bytes. The average
|
|
|
393 |
element size is probably about 5 bytes. Names occupy 12 bytes plus the
|
|
|
394 |
space for the string.
|
|
|
395 |
<p>
|
|
|
396 |
The garbage collector doesn't reclaim portions of arrays obtained with
|
|
|
397 |
<tt>getinterval</tt>, rather it collects entire arrays.
|
|
|
398 |
<hr>
|
|
|
399 |
|
|
|
400 |
<h2><a name="Additional_operators"></a>Additional operators in Ghostscript</h2>
|
|
|
401 |
|
|
|
402 |
<h3><a name="Graphics_and_text"></a>Graphics and text operators</h3>
|
|
|
403 |
|
|
|
404 |
<h4><a name="Transparency"></a>Transparency</h4>
|
|
|
405 |
|
|
|
406 |
<p>
|
|
|
407 |
Ghostscript provides a set of operators for implementing the transparency
|
|
|
408 |
and compositing facilities of PDF 1.4. These are defined only if the
|
|
|
409 |
<b><tt>transpar</tt></b> option was selected when Ghostscript was built. We
|
|
|
410 |
do not attempt to explain the underlying graphics model here: for details,
|
|
|
411 |
see <a
|
|
|
412 |
href="http://partners.adobe.com/asn/developer/technotes.html#acrobat-pdf"
|
|
|
413 |
class="offsite">Adobe
|
|
|
414 |
Technical Note</a> #5407, "<a
|
|
|
415 |
href="http://partners.adobe.com/asn/developer/acrosdk/DOCS/PDF_Transparency.pdf"
|
|
|
416 |
class="offsite">Transparency
|
|
|
417 |
in PDF</a>". Note, however, that
|
|
|
418 |
Ghostscript's model generalizes that of PDF 1.4 in that Ghostscript
|
|
|
419 |
maintains separate alpha and mask values for opacity and shape, rather than
|
|
|
420 |
a single value with a Boolean that says whether it represents opacity or
|
|
|
421 |
shape. EVERYTHING IN THIS SECTION IS SUBJECT TO CHANGE.
|
|
|
422 |
|
|
|
423 |
<h5><a name="Transparency_graphics_state_operators"></a>Graphics state
|
|
|
424 |
operators</h5>
|
|
|
425 |
|
|
|
426 |
<dl>
|
|
|
427 |
<dt><b><tt><modename> .setblendmode -</tt></b>
|
|
|
428 |
<dd>Sets the blending mode in the graphics state. If the mode name is not
|
|
|
429 |
recognized, causes a <b><tt>rangecheck</tt></b> error. The initial value of
|
|
|
430 |
the blending mode is <b><tt>/Compatible</tt></b>.
|
|
|
431 |
</dl>
|
|
|
432 |
|
|
|
433 |
<dl>
|
|
|
434 |
<dt><b><tt>- .currentblendmode <modename></tt></b>
|
|
|
435 |
<dd>Returns the current blending mode.
|
|
|
436 |
</dl>
|
|
|
437 |
|
|
|
438 |
<dl>
|
|
|
439 |
<dt><b><tt><0..1> .setopacityalpha -</tt></b>
|
|
|
440 |
<dd>Sets the opacity alpha value in the graphics state.
|
|
|
441 |
The initial opacity alpha value is 1.
|
|
|
442 |
</dl>
|
|
|
443 |
|
|
|
444 |
<dl>
|
|
|
445 |
<dt><b><tt>- .currentopacityalpha <0..1></tt></b>
|
|
|
446 |
<dd>Returns the current opacity alpha value.
|
|
|
447 |
</dl>
|
|
|
448 |
|
|
|
449 |
<dl>
|
|
|
450 |
<dt><b><tt><0..1> .setshapealpha -</tt></b>
|
|
|
451 |
<dd>Sets the shape alpha value in the graphics state.
|
|
|
452 |
The initial shape alpha value is 1.
|
|
|
453 |
</dl>
|
|
|
454 |
|
|
|
455 |
<dl>
|
|
|
456 |
<dt><b><tt>- .currentshapealpha <0..1></tt></b>
|
|
|
457 |
<dd>Returns the current shape alpha value.
|
|
|
458 |
</dl>
|
|
|
459 |
|
|
|
460 |
<dl>
|
|
|
461 |
<dt><b><tt><bool> .settextknockout -</tt></b>
|
|
|
462 |
<dd>Sets the text knockout flag in the graphics state.
|
|
|
463 |
The initial value of the text knockout flag is <b><tt>true</tt></b>.
|
|
|
464 |
</dl>
|
|
|
465 |
|
|
|
466 |
<dl>
|
|
|
467 |
<dt><b><tt>- .currenttextknockout <bool></tt></b>
|
|
|
468 |
<dd>Returns the current text knockout flag.
|
|
|
469 |
</dl>
|
|
|
470 |
|
|
|
471 |
<h5><a name="Transparency_rendering_stack_operators"></a>Rendering stack
|
|
|
472 |
operators</h5>
|
|
|
473 |
|
|
|
474 |
<p>
|
|
|
475 |
The interpreter state is extended to include a (per-context) rendering stack
|
|
|
476 |
for handling transparency groups and masks (generically, "layers"). Groups
|
|
|
477 |
accumulate a full value for each pixel (paint plus transparency); masks
|
|
|
478 |
accumulate only a coverage value. Layers must be properly nested, i.e., the
|
|
|
479 |
'end' or 'discard' operator must match the corresponding 'begin' operator.
|
|
|
480 |
|
|
|
481 |
<p>
|
|
|
482 |
Beginning and ending layers must nest properly with respect to
|
|
|
483 |
<b><tt>save</tt></b> and <b><tt>restore</tt></b>: <b><tt>save</tt></b> and
|
|
|
484 |
<b><tt>restore</tt></b> do not save and restore the layer stack. Currently,
|
|
|
485 |
layers are not required to nest with respect to <b><tt>gsave</tt></b> and
|
|
|
486 |
<b><tt>grestore</tt></b>, except that the device that is current in the
|
|
|
487 |
graphics state when ending a layer must be the same as the device that was
|
|
|
488 |
current when beginning the layer. THIS AREA IS SUBJECT TO CHANGE.
|
|
|
489 |
|
|
|
490 |
<dl>
|
|
|
491 |
<dt><b><tt><paramdict> <llx> <lly> <urx> <ury>
|
|
|
492 |
.begintransparencygroup -</tt></b>
|
|
|
493 |
<dd>Begins a new transparency group. The <b><tt>ll/ur</tt></b> coordinates
|
|
|
494 |
are the bounding box of the group in the current user coordinate system.
|
|
|
495 |
<b><tt>paramdict</tt></b> has the following keys:
|
|
|
496 |
<dl>
|
|
|
497 |
<dt><b><tt>/Isolated</tt></b>
|
|
|
498 |
<dd>(optional) Boolean; default value = <b><tt>false</tt></b>.
|
|
|
499 |
<dt><b><tt>/Knockout</tt></b>
|
|
|
500 |
<dd>(optional) Boolean; default value = <b><tt>false</tt></b>.
|
|
|
501 |
</dl>
|
|
|
502 |
</dl>
|
|
|
503 |
|
|
|
504 |
<dl>
|
|
|
505 |
<dt><b><tt>- .discardtransparencygroup -</tt></b>
|
|
|
506 |
<dd>Ends and discards the current transparency group.
|
|
|
507 |
</dl>
|
|
|
508 |
|
|
|
509 |
<dl>
|
|
|
510 |
<dt><b><tt>- .endtransparencygroup -</tt></b>
|
|
|
511 |
<dd>Ends the current transparency group, compositing the group being ended
|
|
|
512 |
onto the group that now becomes current.
|
|
|
513 |
</dl>
|
|
|
514 |
|
|
|
515 |
<dl>
|
|
|
516 |
<dt><b><tt><paramdict> <llx> <lly> <urx> <ury>
|
|
|
517 |
.begintransparencymaskgroup -</tt></b>
|
|
|
518 |
<dd>Begins a new transparency mask, which is represented as a group.
|
|
|
519 |
The <b><tt>ll/ur</tt></b> coordinates
|
|
|
520 |
are the bounding box of the mask in the current user coordinate system.
|
|
|
521 |
<b><tt>paramdict</tt></b> has the following keys:
|
|
|
522 |
<dl>
|
|
|
523 |
<dt><b><tt>/Subtype</tt></b>
|
|
|
524 |
<dd>(required) Name, either <b><tt>/Alpha</tt></b> or
|
|
|
525 |
<b><tt>/Luminosity</tt></b>.
|
|
|
526 |
<dt><b><tt>/Background</tt></b>
|
|
|
527 |
<dd>(optional) Array of number.
|
|
|
528 |
<dt><b><tt>/TransferFunction</tt></b>
|
|
|
529 |
<dd>(optional) Function object (produced by applying
|
|
|
530 |
<b><tt>.buildfunction</tt></b> to a Function dictionary).
|
|
|
531 |
</dl>
|
|
|
532 |
</dl>
|
|
|
533 |
|
|
|
534 |
<dl>
|
|
|
535 |
<dt><b><tt>- .begintransparencymaskimage -</tt></b>
|
|
|
536 |
<dd>Begins a new transparency mask, which is represented as a single image.
|
|
|
537 |
</dl>
|
|
|
538 |
</dl>
|
|
|
539 |
|
|
|
540 |
<dl>
|
|
|
541 |
<dt><b><tt>- .discardtransparencymask -</tt></b>
|
|
|
542 |
<dd>Ends and discards the current transparency mask.
|
|
|
543 |
</dl>
|
|
|
544 |
|
|
|
545 |
<dl>
|
|
|
546 |
<dt><b><tt><masknum> .endtransparencymask -</tt></b>
|
|
|
547 |
<dd>Ends the current transparency mask, installing it as the current opacity
|
|
|
548 |
(<b><tt>masknum</tt></b> = 0) or shape (<b><tt>masknum</tt></b> = 1) mask in
|
|
|
549 |
the graphics state.
|
|
|
550 |
</dl>
|
|
|
551 |
|
|
|
552 |
<dl>
|
|
|
553 |
<dt><b><tt><masknum> .inittransparencymask -</tt></b>
|
|
|
554 |
<dd>Resets the current opacity (<b><tt>masknum</tt></b> = 0) or shape
|
|
|
555 |
(<b><tt>masknum</tt></b> = 1) mask to an infinite mask with alpha = 1
|
|
|
556 |
everywhere.
|
|
|
557 |
</dl>
|
|
|
558 |
|
|
|
559 |
<h5><a name="Transparency_ImageType"></a>New ImageType</h5>
|
|
|
560 |
|
|
|
561 |
<p>
|
|
|
562 |
The transparency extension defines a new ImageType 103, similar to ImageType
|
|
|
563 |
3 with the following differences:
|
|
|
564 |
|
|
|
565 |
<ul>
|
|
|
566 |
|
|
|
567 |
<li>The required <b><tt>MaskDict</tt></b> is replaced by two optional
|
|
|
568 |
dictionaries, <b><tt>OpacityMaskDict</tt></b> and
|
|
|
569 |
<b><tt>ShapeMaskDict</tt></b>. If present, these dictionaries must have a
|
|
|
570 |
<b><tt>BitsPerComponent</tt></b> entry, whose value may be greater than 1.
|
|
|
571 |
Note that in contrast to ImageType 3, where any non-zero chunky mask value
|
|
|
572 |
is equivalent to 1, ImageType 103 simply takes the low-order bits of chunky
|
|
|
573 |
mask values.
|
|
|
574 |
|
|
|
575 |
<li>A <b><tt>Matte</tt></b> entry may be present in one or both mask
|
|
|
576 |
dictionaries, indicating premultiplication of the data values. If both
|
|
|
577 |
<b><tt>MaskDict</tt></b>s have a <b><tt>Matte</tt></b> entry and the values
|
|
|
578 |
of the two <b><tt>Matte</tt></b> entries are different, a
|
|
|
579 |
<b><tt>rangecheck</tt></b> error occurs.
|
|
|
580 |
|
|
|
581 |
<li><b><tt>InterleaveType</tt></b> appears in the <b><tt>MaskDict</tt></b>s,
|
|
|
582 |
not the <b><tt>DataDict</tt></b>, because each mask has its own
|
|
|
583 |
<b><tt>InterleaveType</tt></b>. <b><tt>InterleaveType</tt></b> 2
|
|
|
584 |
(interlaced scan lines) is not supported.
|
|
|
585 |
|
|
|
586 |
</ul>
|
|
|
587 |
|
|
|
588 |
<h4><a name="Graphics_state"></a>Other graphics state operators</h4>
|
|
|
589 |
|
|
|
590 |
<dl>
|
|
|
591 |
<dt><b><tt><bool> .setaccuratecurves -</tt></b>
|
|
|
592 |
<dd>Sets a graphics state flag that determines whether curves and arcs,
|
|
|
593 |
when flattened, always start and end with a line that is a segment of the
|
|
|
594 |
tangent; this also causes butt and square caps to be properly perpendicular
|
|
|
595 |
to the tangent. <b><tt>initgraphics</tt></b> sets this flag to false, to
|
|
|
596 |
match other PostScript implementations.
|
|
|
597 |
</dl>
|
|
|
598 |
|
|
|
599 |
<dl>
|
|
|
600 |
<dt><b><tt>- .currentaccuratecurves <bool></tt></b>
|
|
|
601 |
<dd>Returns the current value of the accurate curves flag.
|
|
|
602 |
</dl>
|
|
|
603 |
|
|
|
604 |
<dl>
|
|
|
605 |
<dt><b><tt><int> .setcurvejoin -</tt></b>
|
|
|
606 |
<dd>Obsolete, left for backward compatibility.
|
|
|
607 |
<dd>Sets a graphics state parameter that determines how to treat the joins
|
|
|
608 |
between the line segments produced when a curve is flattened. The parameter
|
|
|
609 |
value may be either -1 or a value acceptable to <b><tt>setlinejoin</tt></b>.
|
|
|
610 |
If the parameter value is -1, the join used for flattened curve line
|
|
|
611 |
segments is given by the current line join parameter in the graphics state
|
|
|
612 |
(except that if the line join value is "none", a bevel join is used), which
|
|
|
613 |
matches the Adobe Red Book, but not some old Adobe implementations; if the curve
|
|
|
614 |
join parameter value is a line join value, that type of join is used for
|
|
|
615 |
flattened curve line segments, regardless of the value of the graphics state
|
|
|
616 |
line join parameter. The initial (and default) value of the curve join
|
|
|
617 |
parameter is -1, causing the compatibility to Red Book and to modern Adobe
|
|
|
618 |
implementations. <b><tt>initgraphics</tt></b> sets the parameter to its
|
|
|
619 |
default value.
|
|
|
620 |
</dl>
|
|
|
621 |
|
|
|
622 |
<dl>
|
|
|
623 |
<dt><b><tt>- .currentcurvejoin <int></tt></b>
|
|
|
624 |
<dd>Obsolete, left for backward compatibility.
|
|
|
625 |
<dd>Returns the current value of the curve join parameter.
|
|
|
626 |
</dl>
|
|
|
627 |
|
|
|
628 |
<dl>
|
|
|
629 |
<dt><b><tt><bool> .setdashadapt -</tt></b>
|
|
|
630 |
<dd>Sets a graphics state flag that determines whether dash patterns do
|
|
|
631 |
(true) or do not (false) automatically scale themselves so that each line
|
|
|
632 |
segment consists of an integral number of pattern repetitions.
|
|
|
633 |
<b><tt>initgraphics</tt></b> sets this flag to false.
|
|
|
634 |
</dl>
|
|
|
635 |
|
|
|
636 |
<dl>
|
|
|
637 |
<dt><b><tt>- .currentdashadapt <bool></tt></b>
|
|
|
638 |
<dd>Returns the current value of the dash adaptation flag.
|
|
|
639 |
</dl>
|
|
|
640 |
|
|
|
641 |
<dl>
|
|
|
642 |
<dt><b><tt><matrix> .setdefaultmatrix -</tt></b>
|
|
|
643 |
<dd>Sets the default matrix that is returned by
|
|
|
644 |
<b><tt>defaultmatrix</tt></b> and installed by <b><tt>initmatrix</tt></b>.
|
|
|
645 |
Ordinary programs should not use this operator.
|
|
|
646 |
</dl>
|
|
|
647 |
|
|
|
648 |
<dl>
|
|
|
649 |
<dt><b><tt><num> <bool> .setdotlength -</tt></b>
|
|
|
650 |
<dd>Sets a graphics state parameter that determines the handling of
|
|
|
651 |
zero-length lines (dots). If the dot length is zero, dots are painted as
|
|
|
652 |
circles if round line caps are in effect, otherwise they are not painted at
|
|
|
653 |
all. If the dot length is non-zero, dots are treated exactly like lines of
|
|
|
654 |
the given length: the length is specified in user coordinates (like line
|
|
|
655 |
width) if <b><tt>bool</tt></b> is false, or in default user coordinates of
|
|
|
656 |
points (units of 1/72in; see the <a href="Devices.htm#Measurements">notes
|
|
|
657 |
on measurements</a> in the documentation on devices) if
|
|
|
658 |
<b><tt>bool</tt></b> is true. Dots occurring as part of dash patterns will
|
|
|
659 |
be oriented correctly; isolated dots will be oriented as though they were
|
|
|
660 |
part of a vertical line. <b><tt>initgraphics</tt></b> sets the dot length
|
|
|
661 |
to zero.
|
|
|
662 |
</dl>
|
|
|
663 |
|
|
|
664 |
<dl>
|
|
|
665 |
<dt><b><tt>- .currentdotlength <num> <bool></tt></b>
|
|
|
666 |
<dd>Returns the current dot length and dot length mode.
|
|
|
667 |
</dl>
|
|
|
668 |
|
|
|
669 |
<dl>
|
|
|
670 |
<dt><b><tt><dx> <dy> .setfilladjust2 -</tt></b>
|
|
|
671 |
<dd>Sets graphics state parameters that cause all filled and stroked
|
|
|
672 |
regions to be "fattened" by the given amount relative to an algorithm that
|
|
|
673 |
only paints pixels whose centers fall within the region to be painted.
|
|
|
674 |
<b><tt>dx</tt></b> and <b><tt>dy</tt></b> are numbers between 0 and 0.5,
|
|
|
675 |
measured in device space. The only two values that are likely to be useful
|
|
|
676 |
are 0, which gives a pure center-of-pixel rule, and 0.5, which gives
|
|
|
677 |
Adobe's any-part-of-pixel rule. (0.5 is treated slightly specially in
|
|
|
678 |
order to create half-open pixels per Adobe's specification.)
|
|
|
679 |
</dl>
|
|
|
680 |
|
|
|
681 |
<dl>
|
|
|
682 |
<dt><b><tt>- .currentfilladjust2 <dx> <dy></tt></b>
|
|
|
683 |
<dd>Returns the current fill adjustment values.
|
|
|
684 |
</dl>
|
|
|
685 |
|
|
|
686 |
<dl>
|
|
|
687 |
<dt><b><tt><bool> .setlimitclamp -</tt></b>
|
|
|
688 |
<dd>Sets a graphics state flag that determines whether attempts to set the
|
|
|
689 |
current point outside the internally representable range should clamp the
|
|
|
690 |
value to the largest representable value (true) or give a
|
|
|
691 |
<b><tt>limitcheck</tt></b> error (false). <b><tt>initgraphics</tt></b> sets
|
|
|
692 |
this flag to false, to match other PostScript implementations.
|
|
|
693 |
</dl>
|
|
|
694 |
|
|
|
695 |
<dl>
|
|
|
696 |
<dt><b><tt>- .currentlimitclamp <bool></tt></b>
|
|
|
697 |
<dd>Returns the current value of the limit clamp flag.
|
|
|
698 |
</dl>
|
|
|
699 |
|
|
|
700 |
<dl>
|
|
|
701 |
<dt><b><tt><int> .setoverprintmode -</tt></b>
|
|
|
702 |
<dd>Sets the overprint mode in the graphics state. Legal values are 0 or 1.
|
|
|
703 |
Per the PDF 1.3 specification, if the overprint mode is 1, then when the
|
|
|
704 |
current color space is <b><tt>DeviceCMYK</tt></b>, color components whose
|
|
|
705 |
value is 0 do not write into the target, rather than writing a 0 value.
|
|
|
706 |
THIS BEHAVIOR IS NOT IMPLEMENTED YET. The initial value of the overprint
|
|
|
707 |
mode is 0.
|
|
|
708 |
</dl>
|
|
|
709 |
|
|
|
710 |
<dl>
|
|
|
711 |
<dt><b><tt>- .currentoverprintmode <int></tt></b>
|
|
|
712 |
<dd>Returns the current overprint mode.
|
|
|
713 |
</dl>
|
|
|
714 |
|
|
|
715 |
<h4><a name="Path"></a>Path operators</h4>
|
|
|
716 |
|
|
|
717 |
<dl>
|
|
|
718 |
<dt><b><tt>- .dashpath -</tt></b>
|
|
|
719 |
<dd>If there is no current dash pattern, does nothing. Otherwise, does the
|
|
|
720 |
equivalent of <b><tt>flattenpath</tt></b> and then chops up the path as
|
|
|
721 |
determined by the dash pattern.
|
|
|
722 |
</dl>
|
|
|
723 |
|
|
|
724 |
<dl>
|
|
|
725 |
<dt><b><tt><x> <y> <width> <height> .rectappend -</tt></b>
|
|
|
726 |
<dt><b><tt><numarray> .rectappend -</tt></b>
|
|
|
727 |
<dt><b><tt><numstring> .rectappend -</tt></b>
|
|
|
728 |
<dd>Appends a rectangle or rectangles to the current path, in the same
|
|
|
729 |
manner as <b><tt>rectfill</tt></b>, <b><tt>rectclip</tt></b>, etc. Defined
|
|
|
730 |
only if the <b><tt>dps</tt></b> or <b><tt>level2</tt></b> option was
|
|
|
731 |
selected when Ghostscript was built.
|
|
|
732 |
</dl>
|
|
|
733 |
|
|
|
734 |
<h4><a name="Painting"></a>Painting operators</h4>
|
|
|
735 |
|
|
|
736 |
<p>
|
|
|
737 |
Ghostscript supports an experimental extension of the PostScript imaging
|
|
|
738 |
model to include <b><tt>RasterOp</tt></b> and some related facilities.
|
|
|
739 |
This extension is available only if the <b><tt>rasterop</tt></b> option was
|
|
|
740 |
selected when building Ghostscript.
|
|
|
741 |
|
|
|
742 |
<p>
|
|
|
743 |
With the <b><tt>RasterOp</tt></b> extension, imaging operations compute a
|
|
|
744 |
function <b>D = f(D,S,T)</b> in RGB space, where <b>f</b> is an
|
|
|
745 |
arbitrary 3-input Boolean function, <b>D</b> is the destination (frame
|
|
|
746 |
buffer or print buffer), <b>S</b> is the source (described below), and
|
|
|
747 |
<b>T</b> is the texture (the current PostScript color, which may be a
|
|
|
748 |
pattern). The source and texture depend on the PostScript imaging
|
|
|
749 |
operation:
|
|
|
750 |
|
|
|
751 |
<ul>
|
|
|
752 |
<li>For <b><tt>fill</tt></b> and <b><tt>stroke</tt></b>, the source is
|
|
|
753 |
solid black, covering the region to be painted; the texture is the current
|
|
|
754 |
PostScript color.
|
|
|
755 |
|
|
|
756 |
<li>For <b><tt>show</tt></b> and <b><tt>imagemask</tt></b>, the source is
|
|
|
757 |
solid black, covering the pixels to be painted; the texture is the current
|
|
|
758 |
PostScript color.
|
|
|
759 |
|
|
|
760 |
<li>For <b><tt>image</tt></b> and <b><tt>colorimage</tt></b>, the source is
|
|
|
761 |
the image data; the texture depends on an optional Boolean parameter,
|
|
|
762 |
<b><tt>CombineWithColor</tt></b>, in the image dictionary. If
|
|
|
763 |
<b><tt>CombineWithColor</tt></b> is false (the default), the texture is
|
|
|
764 |
solid black. If <b><tt>CombineWithColor</tt></b> is true, the texture is
|
|
|
765 |
the current color. For the non-dictionary form of the image operator,
|
|
|
766 |
<b><tt>CombineWithColor</tt></b> is considered to be false.
|
|
|
767 |
</ul>
|
|
|
768 |
|
|
|
769 |
<p>
|
|
|
770 |
The <b><tt>rasterop</tt></b> option adds the following operators:
|
|
|
771 |
|
|
|
772 |
<dl>
|
|
|
773 |
<dt><b><tt><int8> .setrasterop -</tt></b>
|
|
|
774 |
<dd>Sets the <b><tt>RasterOp</tt></b> function in the graphics state. The
|
|
|
775 |
default function is 252, Source | Texture.
|
|
|
776 |
</dl>
|
|
|
777 |
|
|
|
778 |
<dl>
|
|
|
779 |
<dt><b><tt>- .currentrasterop <int8></tt></b>
|
|
|
780 |
<dd>Returns the current <b><tt>RasterOp</tt></b> function.
|
|
|
781 |
</dl>
|
|
|
782 |
|
|
|
783 |
<dl>
|
|
|
784 |
<dt><b><tt><bool> .setsourcetransparent -</tt></b>
|
|
|
785 |
<dd>Sets source transparency in the graphics state. When source
|
|
|
786 |
transparency is true, white source pixels prevent storing into the
|
|
|
787 |
destination, regardless of what the <b><tt>RasterOp</tt></b> function
|
|
|
788 |
returns. The default source transparency is false.
|
|
|
789 |
</dl>
|
|
|
790 |
|
|
|
791 |
<dl>
|
|
|
792 |
<dt><b><tt>- .currentsourcetransparent <bool> -</tt></b>
|
|
|
793 |
<dd>Returns the current source transparency.
|
|
|
794 |
</dl>
|
|
|
795 |
|
|
|
796 |
<dl>
|
|
|
797 |
<dt><b><tt><bool> .settexturetransparent -</tt></b>
|
|
|
798 |
<dd>Sets texture transparency in the graphics state. When texture
|
|
|
799 |
transparency is true, white texture pixels prevent storing into the
|
|
|
800 |
destination, regardless of what the <b><tt>RasterOp</tt></b> function
|
|
|
801 |
returns. The default texture transparency is false.
|
|
|
802 |
</dl>
|
|
|
803 |
|
|
|
804 |
<dl>
|
|
|
805 |
<dt><b><tt>- .currenttexturetransparent <bool> -</tt></b>
|
|
|
806 |
<dd>Returns the current texture transparency.
|
|
|
807 |
</dl>
|
|
|
808 |
|
|
|
809 |
<p>
|
|
|
810 |
For more information on RasterOp and transparency, please consult chapter 5
|
|
|
811 |
of the "PCL 5 Color Technical Reference Manual",
|
|
|
812 |
<a href="http://www.hp.com/cposupport/printers/support_doc/bpl01354.html">Hewlett-Packard
|
|
|
813 |
Manual Part No. 5961-0635</a>.
|
|
|
814 |
|
|
|
815 |
<h4><a name="Character"></a>Character operators</h4>
|
|
|
816 |
|
|
|
817 |
<dl>
|
|
|
818 |
<dt><b><tt><string> <bool> .charboxpath -</tt></b>
|
|
|
819 |
<dd>For each character <b>C</b> in the rendering of <string>, let the
|
|
|
820 |
bounding box of <b>C</b> <b><em>in device space</em></b> be the four
|
|
|
821 |
<b><em>user-space</em></b> points p1x/y, p2x/y, p3x/y, and p4x/y. For each
|
|
|
822 |
character in order, <b><tt>.charboxpath</tt></b> appends the following to
|
|
|
823 |
the current path:
|
|
|
824 |
|
|
|
825 |
<ul><li>If <b><tt><bool></tt></b> is true, the equivalent of:
|
|
|
826 |
|
|
|
827 |
<blockquote>
|
|
|
828 |
p1x p1y <b><tt>moveto</tt></b><br>
|
|
|
829 |
p2x p2y <b><tt>lineto</tt></b><br>
|
|
|
830 |
p3x p3y <b><tt>lineto</tt></b><br>
|
|
|
831 |
p4x p4y <b><tt>lineto</tt></b><br>
|
|
|
832 |
<b><tt>closepath</tt></b>
|
|
|
833 |
</blockquote>
|
|
|
834 |
</ul>
|
|
|
835 |
|
|
|
836 |
<p>
|
|
|
837 |
This creates a path whose <b><tt>pathbbox</tt></b> is the
|
|
|
838 |
<b><tt>bbox</tt></b> of the string.
|
|
|
839 |
|
|
|
840 |
<ul><li>If <b><tt><bool></tt></b> is false, the equivalent of:
|
|
|
841 |
|
|
|
842 |
<blockquote>
|
|
|
843 |
p1x p1y <b><tt>moveto</tt></b><br>
|
|
|
844 |
p3x p3y <b><tt>lineto</tt></b>
|
|
|
845 |
</blockquote>
|
|
|
846 |
</ul>
|
|
|
847 |
|
|
|
848 |
<p>
|
|
|
849 |
If the CTM is well-behaved (consists only of reflection, scaling, and
|
|
|
850 |
rotation by multiples of 90 degrees), this too creates a (simpler) path
|
|
|
851 |
whose <b><tt>pathbbox</tt></b> is the <b><tt>bbox</tt></b> of the string.
|
|
|
852 |
</dl>
|
|
|
853 |
|
|
|
854 |
<dl>
|
|
|
855 |
<dt><b><tt><font> <charname|charcode> <charname> <charstring> .type1execchar -</tt></b>
|
|
|
856 |
<dd>Does all the work for rendering a Type 1 outline. This operator, like
|
|
|
857 |
<b><tt>setcharwidth</tt></b> and <b><tt>setcachedevice</tt></b>, is valid
|
|
|
858 |
only in the context of a show operator -- that is, it must only be called
|
|
|
859 |
from within a <b><tt>BuildChar</tt></b> or <b><tt>BuildGlyph</tt></b>
|
|
|
860 |
procedure.
|
|
|
861 |
</dl>
|
|
|
862 |
|
|
|
863 |
<dl>
|
|
|
864 |
<dt><b><tt><font> <charcode> %Type1BuildChar -</tt></b>
|
|
|
865 |
<dd>This is not a new operator: rather, it is a name known specially to the
|
|
|
866 |
interpreter. Whenever the interpreter needs to render a character (during
|
|
|
867 |
a ...<b><tt>show</tt></b>, <b><tt>stringwidth</tt></b>, or
|
|
|
868 |
<b><tt>charpath</tt></b>), it looks up the name <b><tt>BuildChar</tt></b>
|
|
|
869 |
in the font dictionary to find a procedure to run. If it does not find
|
|
|
870 |
this name, and if the <b><tt>FontType</tt></b> is 1, the interpreter
|
|
|
871 |
instead uses the value (looked up on the dictionary stack in the usual way)
|
|
|
872 |
of the name <b><tt>%Type1BuildChar</tt></b>.
|
|
|
873 |
|
|
|
874 |
<p>
|
|
|
875 |
The standard definition of <b><tt>%Type1BuildChar</tt></b> is in the
|
|
|
876 |
initialization file <b><tt>gs_type1.ps</tt></b>. Users should not need to
|
|
|
877 |
redefine <b><tt>%Type1BuildChar</tt></b>, except perhaps for tracing or
|
|
|
878 |
debugging.
|
|
|
879 |
</dl>
|
|
|
880 |
|
|
|
881 |
<dl>
|
|
|
882 |
<dt><b><tt><font> <charname> %Type1BuildGlyph -</tt></b>
|
|
|
883 |
<dd>Provides the Type 1 implementation of <b><tt>BuildGlyph</tt></b>.
|
|
|
884 |
</dl>
|
|
|
885 |
|
|
|
886 |
<h3><a name="Other"></a>Other operators</h3>
|
|
|
887 |
|
|
|
888 |
<h4><a name="Mathematical"></a>Mathematical operators</h4>
|
|
|
889 |
|
|
|
890 |
<dl>
|
|
|
891 |
<dt><b><tt><number> arccos <number></tt></b>
|
|
|
892 |
<dd>Computes the arc cosine of a number between -1 and 1.
|
|
|
893 |
</dl>
|
|
|
894 |
|
|
|
895 |
<dl>
|
|
|
896 |
<dt><b><tt><number> arcsin <number></tt></b>
|
|
|
897 |
<dd>Computes the arc sine of a number between -1 and 1.
|
|
|
898 |
</dl>
|
|
|
899 |
|
|
|
900 |
<h4><a name="Dictionary"></a>Dictionary operators</h4>
|
|
|
901 |
|
|
|
902 |
<dl>
|
|
|
903 |
<dt><b><tt>mark <key1> <value1> <key2> <value2> ... .dicttomark <dict></tt></b>
|
|
|
904 |
<dd>Creates and returns a dictionary with the given keys and values. This
|
|
|
905 |
is the same as the PostScript Level 2 <b><tt>>></tt></b> operator,
|
|
|
906 |
but is available even in Level 1 configurations.
|
|
|
907 |
</dl>
|
|
|
908 |
|
|
|
909 |
<dl>
|
|
|
910 |
<dt><b><tt><dict> <key> <value> .forceput - </tt></b>
|
|
|
911 |
<dd>Equivalent to <b><tt>put</tt></b>, but works even if
|
|
|
912 |
<b><tt>dict</tt></b> is not writable, and (if <b><tt>dict</tt></b> is
|
|
|
913 |
<b><tt>systemdict</tt></b> or the current save level is 0) even if
|
|
|
914 |
<b><tt>dict</tt></b> is in global VM and <b><tt>key</tt></b> and/or
|
|
|
915 |
<b><tt>value</tt></b> is in local VM. <strong>This operator should be used
|
|
|
916 |
only initialization code, and only in executeonly procedures: it must not be
|
|
|
917 |
accessible after initialization.</strong>
|
|
|
918 |
</dl>
|
|
|
919 |
|
|
|
920 |
<dl>
|
|
|
921 |
<dt><b><tt><dict> <key> .forceundef - </tt></b>
|
|
|
922 |
<dd>Equivalent to <b><tt>undef</tt></b>, but works even if
|
|
|
923 |
<b><tt>dict</tt></b> is not writable. <strong>This operator should be used
|
|
|
924 |
only initialization code, and only in executeonly procedures: it must not be
|
|
|
925 |
accessible after initialization.</strong>
|
|
|
926 |
</dl>
|
|
|
927 |
|
|
|
928 |
|
|
|
929 |
<dl>
|
|
|
930 |
<dt><b><tt><dict> <key> .knownget <value> true</tt></b>
|
|
|
931 |
<dt><b><tt><dict> <key> .knownget false</tt></b>
|
|
|
932 |
<dd>Combines <b><tt>known</tt></b> and <b><tt>get</tt></b> in the
|
|
|
933 |
obvious way.
|
|
|
934 |
</dl>
|
|
|
935 |
|
|
|
936 |
<dl>
|
|
|
937 |
<dt><b><tt><dict> <integer> .setmaxlength -</tt></b>
|
|
|
938 |
<dd>Sets the capacity (<b><tt>maxlength</tt></b>) of a dictionary.
|
|
|
939 |
Causes a <b><tt>dictfull</tt></b> error if the dictionary has more
|
|
|
940 |
occupied entries than the requested capacity.
|
|
|
941 |
</dl>
|
|
|
942 |
|
|
|
943 |
<h4><a name="String"></a>String and name operators</h4>
|
|
|
944 |
|
|
|
945 |
<dl>
|
|
|
946 |
<dt><b><tt><integer> .bytestring <bytestring></tt></b>
|
|
|
947 |
<dd>Allocates and returns a bytestring, a special data type that can be
|
|
|
948 |
larger than the maximum size of a string (64K-1 bytes) and can be used in
|
|
|
949 |
place of a string with a very few operators.
|
|
|
950 |
</dl>
|
|
|
951 |
|
|
|
952 |
<dl>
|
|
|
953 |
<dt><b><tt><name> .namestring <string></tt></b>
|
|
|
954 |
<dd>Returns the (read-only) string for a name.
|
|
|
955 |
</dl>
|
|
|
956 |
|
|
|
957 |
<dl>
|
|
|
958 |
<dt><b><tt><string> <charstring> .stringbreak <index|null></tt></b>
|
|
|
959 |
<dd>Searches for a character in <b><tt>string</tt></b> that appears
|
|
|
960 |
somewhere in <b><tt>charstring</tt></b>. If such a character is found,
|
|
|
961 |
returns the index of the first such character; if no such character is
|
|
|
962 |
found, returns <b><tt>null</tt></b>.
|
|
|
963 |
</dl>
|
|
|
964 |
|
|
|
965 |
<dl>
|
|
|
966 |
<dt><b><tt><obj> <pattern> .stringmatch <bool></tt></b>
|
|
|
967 |
<dd>Matches <b><tt>obj</tt></b> against a pattern in which '*' matches 0 or
|
|
|
968 |
more characters and '?' matches any single character. If
|
|
|
969 |
<b><tt>obj</tt></b> is a string or a name, matches its characters against
|
|
|
970 |
the pattern; if <b><tt>obj</tt></b> is of any other type, the result is
|
|
|
971 |
<b><tt>true</tt></b> if the pattern is the single character "*" and
|
|
|
972 |
<b><tt>false</tt></b> otherwise.
|
|
|
973 |
</dl>
|
|
|
974 |
|
|
|
975 |
<dl>
|
|
|
976 |
<dt><b><tt><state> <fromString> <toString> .type1encrypt <newState> <toSubstring></tt></b>
|
|
|
977 |
<dd>Encrypts <b><tt>fromString</tt></b> according to the algorithm for
|
|
|
978 |
Adobe Type 1 fonts, writing the result into <b><tt>toString</tt></b>.
|
|
|
979 |
<b><tt>toString</tt></b> must be at least as long as
|
|
|
980 |
<b><tt>fromString</tt></b>, or a rangecheck error occurs.
|
|
|
981 |
<b><tt>state</tt></b> is the initial state of the encryption algorithm (a
|
|
|
982 |
16-bit non-negative integer); <b><tt>newState</tt></b> is the new state of
|
|
|
983 |
the algorithm.
|
|
|
984 |
</dl>
|
|
|
985 |
|
|
|
986 |
<dl>
|
|
|
987 |
<dt><b><tt><state> <fromString> <toString> .type1decrypt <newState> <toSubstring></tt></b>
|
|
|
988 |
<dd>Decrypts <b><tt>fromString</tt></b> according to the algorithm for
|
|
|
989 |
Adobe Type 1 fonts, writing the result into <b><tt>toString</tt></b>.
|
|
|
990 |
Other specifications are as for <b><tt>type1encrypt</tt></b>.
|
|
|
991 |
</dl>
|
|
|
992 |
|
|
|
993 |
<h4><a name="Relational"></a>Relational operators</h4>
|
|
|
994 |
|
|
|
995 |
<dl>
|
|
|
996 |
<dt><b><tt><number|string> <number|string> max <number|string></tt></b>
|
|
|
997 |
<dd>Returns the larger of two numbers or strings.
|
|
|
998 |
</dl>
|
|
|
999 |
|
|
|
1000 |
<dl>
|
|
|
1001 |
<dt><b><tt><number|string> <number|string> min <number|string></tt></b>
|
|
|
1002 |
<dd>Returns the smaller of two numbers or strings.
|
|
|
1003 |
</dl>
|
|
|
1004 |
|
|
|
1005 |
<h4><a name="File"></a>File operators</h4>
|
|
|
1006 |
|
|
|
1007 |
<dl>
|
|
|
1008 |
<dt><b><tt><file> .filename <string> true</tt></b>
|
|
|
1009 |
<dt><b><tt><file> .filename false</tt></b>
|
|
|
1010 |
<dd>If the file was opened by the <b><tt>file</tt></b> or
|
|
|
1011 |
<b><tt>.tempfile</tt></b> operator, returns the file name and
|
|
|
1012 |
<b><tt>true</tt></b>; if the file is a filter, returns
|
|
|
1013 |
<b><tt>false</tt></b>.
|
|
|
1014 |
</dl>
|
|
|
1015 |
|
|
|
1016 |
<dl>
|
|
|
1017 |
<dt><b><tt><file> .fileposition <integer> true</tt></b>
|
|
|
1018 |
<dd>Returns the position of <b><tt>file</tt></b>. Unlike the standard
|
|
|
1019 |
<b><tt>fileposition</tt></b> operator, which causes an error if the file is
|
|
|
1020 |
not positionable, <b><tt>.fileposition</tt></b> works on all files,
|
|
|
1021 |
including filters: for non-positionable files, it returns the total number
|
|
|
1022 |
of bytes read or written since the file was opened.
|
|
|
1023 |
</dl>
|
|
|
1024 |
|
|
|
1025 |
<dl>
|
|
|
1026 |
<dt><b><tt><string> findlibfile <foundstring> <file> true</tt></b>
|
|
|
1027 |
<dt><b><tt><string> findlibfile <string> false</tt></b>
|
|
|
1028 |
<dd>Opens the file of the given name for reading, searching through
|
|
|
1029 |
directories <a href="Use.htm#Finding_files">as described in the usage
|
|
|
1030 |
documentation</a>. If the search fails, <b><tt>findlibfile</tt></b> simply
|
|
|
1031 |
pushes false on the stack and returns, rather than causing an error.
|
|
|
1032 |
</dl>
|
|
|
1033 |
|
|
|
1034 |
<dl>
|
|
|
1035 |
<dt><b><tt><file> <string> .peekstring <substring> <filled_bool></tt></b>
|
|
|
1036 |
<dd>Reads bytes from a file like <b><tt>readstring</tt></b>, but also leaves
|
|
|
1037 |
the bytes in the file buffer so they will be read again by a subsequent read
|
|
|
1038 |
operation. Currently gives a <b><tt>rangecheck</tt></b> error if
|
|
|
1039 |
<b><tt>string</tt></b> is larger than the file's buffer.
|
|
|
1040 |
</dl>
|
|
|
1041 |
|
|
|
1042 |
<a name=Tempfile></a>
|
|
|
1043 |
<dl>
|
|
|
1044 |
<dt><b><tt><prefix_string|null> <access_string> .tempfile
|
|
|
1045 |
<string> <file></tt></b>
|
|
|
1046 |
<dd>Creates and opens a temporary file
|
|
|
1047 |
like the <b><tt>file</tt></b> operator, also returning the file name. There
|
|
|
1048 |
are three cases for the <b><tt><prefix_string|null></tt></b> operand:
|
|
|
1049 |
|
|
|
1050 |
<ul>
|
|
|
1051 |
<p>
|
|
|
1052 |
<li><b><tt>null</tt></b>: create the file in the same directory and with the
|
|
|
1053 |
same name conventions as other temporary files created by the Ghostscript
|
|
|
1054 |
implementation on this platform. E.g., the temporary file might be named
|
|
|
1055 |
<b><tt>/tmp/gs_a1234</tt></b>.
|
|
|
1056 |
<p>
|
|
|
1057 |
<li>A string that contains only alphanumeric characters, underline,
|
|
|
1058 |
and dash: create the file in the standard temporary directory, but use
|
|
|
1059 |
the
|
|
|
1060 |
<b><tt><prefix_string></tt></b> as the first part of the file name.
|
|
|
1061 |
E.g., if <b><tt><prefix_string></tt></b> is <b><tt>xx</tt></b>, the
|
|
|
1062 |
temporary file might be named <b><tt>/tmp/xxa1234</tt></b>.
|
|
|
1063 |
<p>
|
|
|
1064 |
<li>A string that is the beginning of an absolute file name: use the
|
|
|
1065 |
<b><tt><prefix_string></tt></b> as the first part of the file name.
|
|
|
1066 |
E.g., if <b><tt><prefix_string></tt></b> is
|
|
|
1067 |
<b><tt>/my/tmpdir/zz</tt></b>, the temporary file might be named
|
|
|
1068 |
<b><tt>/my/tmpdir/zza1234</tt></b>.
|
|
|
1069 |
<p>
|
|
|
1070 |
When running in <b><tt>SAFER</tt></b> mode, the absolute path must
|
|
|
1071 |
be one of the strings on the list given by the <b><tt>PermitFileWriting</tt></b>
|
|
|
1072 |
userparameter. Temporary files created with <b><tt>.tempfile</tt></b> can
|
|
|
1073 |
be deleted when in SAFER mode, and can be renamed to one of the paths
|
|
|
1074 |
that is on <b>both</b> the PermitFileControl and PermitFileWriting
|
|
|
1075 |
paths.
|
|
|
1076 |
</ul>
|
|
|
1077 |
|
|
|
1078 |
</dl>
|
|
|
1079 |
|
|
|
1080 |
<dl>
|
|
|
1081 |
<dt><b><tt><file> <integer> .unread -</tt></b>
|
|
|
1082 |
<dd>Pushes back the last-read character onto the front of the file. If the
|
|
|
1083 |
file is open only for writing, or if the integer argument is not the same
|
|
|
1084 |
as the last character read from the file, causes an <b><tt>ioerror</tt></b>
|
|
|
1085 |
error. May also cause an <b><tt>ioerror</tt></b> if the last operation on
|
|
|
1086 |
the file was not a reading operation. This operator is now deprecated:
|
|
|
1087 |
use <b><tt>.peekstring</tt></b> in new code.
|
|
|
1088 |
</dl>
|
|
|
1089 |
|
|
|
1090 |
<p>
|
|
|
1091 |
Ghostscript also supports the following <b><tt>IODevice</tt></b> in
|
|
|
1092 |
addition to a subset of those defined in the Adobe documentation:
|
|
|
1093 |
<ul>
|
|
|
1094 |
<li>
|
|
|
1095 |
<b><tt>%pipe%command</tt></b>, which opens a pipe on the given command.
|
|
|
1096 |
This is supported only on operating systems that provide
|
|
|
1097 |
<b><tt>popen</tt></b> (primarily Unix systems, and not all of those).
|
|
|
1098 |
<p>
|
|
|
1099 |
<li>
|
|
|
1100 |
<b><tt>%disk#%</tt></b>, which emulates the %disk0
|
|
|
1101 |
through %disk9 devices on some Adobe PostScript printers. This pseudo
|
|
|
1102 |
device provides a flat filenaming system with a user definable location
|
|
|
1103 |
for the files (/Root). These devices will only be present if the
|
|
|
1104 |
diskn.dev feature is specified during the build.
|
|
|
1105 |
<p>
|
|
|
1106 |
This feature is intended to allow compatibility with font downloaders
|
|
|
1107 |
that expect to store fonts on the %disk device of the printer.
|
|
|
1108 |
<p>
|
|
|
1109 |
Use of the %disk#% devices requires that the location of files be given
|
|
|
1110 |
by the user setting the /Root device parameter. The syntax for setting
|
|
|
1111 |
the /Root parameter is:<pre>
|
|
|
1112 |
mark /Root (directory_specification) (%disk#) .putdevparams
|
|
|
1113 |
</pre>
|
|
|
1114 |
For example, to store the files of the %disk0 device on the directory
|
|
|
1115 |
/tmp/disk0, use:<pre>
|
|
|
1116 |
mark /Root (/tmp/disk0/) (%disk0) .putdevparams
|
|
|
1117 |
</pre>
|
|
|
1118 |
The files will be stored in the specified directory with arbitrary names.
|
|
|
1119 |
A mapping file is used to store the association between the file
|
|
|
1120 |
names given for the file operations on the %diskn# device and the file
|
|
|
1121 |
that resides in the /Root directory.
|
|
|
1122 |
</ul>
|
|
|
1123 |
|
|
|
1124 |
<h4><a name="Virtual_memory"></a>Virtual memory operators</h4>
|
|
|
1125 |
|
|
|
1126 |
<dl>
|
|
|
1127 |
<dt><b><tt><save> .forgetsave -</tt></b>
|
|
|
1128 |
<dd>Cancels the effect of a save, making it as though the save never
|
|
|
1129 |
happened.
|
|
|
1130 |
</dl>
|
|
|
1131 |
|
|
|
1132 |
<h4><a name="Miscellaneous"></a>Miscellaneous operators</h4>
|
|
|
1133 |
|
|
|
1134 |
<dl>
|
|
|
1135 |
<dt><b><tt><array> bind <array></tt></b>
|
|
|
1136 |
<dd>Depending on the command line parameters <b><tt>bind</tt></b> is redefined as:
|
|
|
1137 |
</dl>
|
|
|
1138 |
|
|
|
1139 |
<blockquote><table cellpadding=0 cellspacing=0>
|
|
|
1140 |
<tr valign=bottom>
|
|
|
1141 |
<th valign=bottom align=left>Flag
|
|
|
1142 |
<td>
|
|
|
1143 |
<th valign=bottom align=left>Definition
|
|
|
1144 |
<tr> <td colspan=3><hr>
|
|
|
1145 |
<tr valign=top> <td>NOBIND
|
|
|
1146 |
<td>
|
|
|
1147 |
<td>/bind {} def ;
|
|
|
1148 |
no operation, returns the argument
|
|
|
1149 |
<tr valign=top> <td>DELAYBIND
|
|
|
1150 |
<td>
|
|
|
1151 |
<td>returns the argument, stores the argument for later use by <b><tt>.bindnow</b></tt>
|
|
|
1152 |
</table></blockquote>
|
|
|
1153 |
|
|
|
1154 |
|
|
|
1155 |
<dl>
|
|
|
1156 |
<dt><b><tt><array> .bind <array></tt></b>
|
|
|
1157 |
<dd>Performs standard <b><tt>bind</tt></b> operation as defined in PLRM regardless of
|
|
|
1158 |
NOBIND or DELAYBIND flags.
|
|
|
1159 |
</dl>
|
|
|
1160 |
|
|
|
1161 |
<a name="bindnow"></a>
|
|
|
1162 |
<dl>
|
|
|
1163 |
<dt><b><tt>- .bindnow -</tt></b>
|
|
|
1164 |
<dd>Applies <b><tt>bind</tt></b> operator to all savad procedures after binding has been
|
|
|
1165 |
deferred through -dDELAYBIND. Note that idiom recognition has no effect for the deferred
|
|
|
1166 |
binding because the value returned from <b><tt>bind</tt></b> is discarded.
|
|
|
1167 |
<p>
|
|
|
1168 |
Since v. 8.12 <b><tt>.bindnow</tt></b> undefines itself and restores standard definition of
|
|
|
1169 |
<b><tt>bind</tt></b> operator. In earlier versions after calling <b><tt>.bindnow</tt></b>,
|
|
|
1170 |
the postscript <b><tt>bind</tt></b> operator needs to be rebound to the internal implementation
|
|
|
1171 |
<b><tt>.bind</tt></b>, as in this fragment from the ps2ascii script:
|
|
|
1172 |
<blockquote><pre><tt>DELAYBIND {
|
|
|
1173 |
.bindnow
|
|
|
1174 |
/bind /.bind load def
|
|
|
1175 |
} if
|
|
|
1176 |
</tt></pre></blockquote>
|
|
|
1177 |
This is necessary for correct behavior with later code that uses the <b><tt>bind</tt></b> operator.
|
|
|
1178 |
</dl>
|
|
|
1179 |
|
|
|
1180 |
<dl>
|
|
|
1181 |
<dt><b><tt><obj1> <obj2> ... <objn> <n> .execn ...</tt></b>
|
|
|
1182 |
<dd>This executes <b><tt>obj1</tt></b> through <b><tt>objn</tt></b> in that
|
|
|
1183 |
order, essentially equivalent to
|
|
|
1184 |
|
|
|
1185 |
<blockquote><pre>
|
|
|
1186 |
<obj1> <obj2> ... <objn> <n> array astore {exec} forall
|
|
|
1187 |
</pre></blockquote>
|
|
|
1188 |
|
|
|
1189 |
<p>
|
|
|
1190 |
except that it doesn't actually create the array.
|
|
|
1191 |
</dl>
|
|
|
1192 |
|
|
|
1193 |
<dl>
|
|
|
1194 |
<dt><b><tt><string> getenv <string> true</tt></b>
|
|
|
1195 |
<dt><b><tt><string> getenv false</tt></b>
|
|
|
1196 |
<dd>Looks up a name in the shell environment. If the name is found,
|
|
|
1197 |
returns the corresponding value and true; if the name is not found, returns
|
|
|
1198 |
false.
|
|
|
1199 |
</dl>
|
|
|
1200 |
|
|
|
1201 |
<dl>
|
|
|
1202 |
<dt><b><tt><name> <array> .makeoperator <operator></tt></b>
|
|
|
1203 |
<dd>Constructs and returns a new operator that is actually the given
|
|
|
1204 |
procedure in disguise. The name is only used for printing. The operator
|
|
|
1205 |
has the executable attribute.
|
|
|
1206 |
|
|
|
1207 |
<p>
|
|
|
1208 |
Operators defined in this way do one other thing besides running the
|
|
|
1209 |
procedure: if an error occurs during the execution of the procedure, and
|
|
|
1210 |
there has been no net reduction in operand or dictionary stack depth, the
|
|
|
1211 |
operand or dictionary stack pointer respectively is reset to its position
|
|
|
1212 |
at the beginning of the procedure.
|
|
|
1213 |
</dl>
|
|
|
1214 |
|
|
|
1215 |
<dl>
|
|
|
1216 |
<dt><b><tt><string> <boolean> .setdebug -</tt></b>
|
|
|
1217 |
<dd>If the Ghostscript interpreter was built with the <b><tt>DEBUG</tt></b>
|
|
|
1218 |
flag set, sets or resets any subset of the debugging flags normally
|
|
|
1219 |
controlled by <b><tt>-Z</tt></b> in the command line. Has no effect
|
|
|
1220 |
otherwise.
|
|
|
1221 |
</dl>
|
|
|
1222 |
|
|
|
1223 |
<dl>
|
|
|
1224 |
<dt><b><tt>- .oserrno <errno></tt></b>
|
|
|
1225 |
<dd>Returns the error code for the most recent operating system error.
|
|
|
1226 |
</dl>
|
|
|
1227 |
|
|
|
1228 |
<dl>
|
|
|
1229 |
<dt><b><tt>- .oserrorstring <string></tt></b>
|
|
|
1230 |
<dd>Returns the error string for the most recent operating system error.
|
|
|
1231 |
</dl>
|
|
|
1232 |
|
|
|
1233 |
<a name="Runandhide"></a>
|
|
|
1234 |
<dl>
|
|
|
1235 |
<dt><b><tt><array> <procedure> .runandhide ... <array></tt></b>
|
|
|
1236 |
<dd>Runs the <i><tt><procedure></tt></i> after removing the
|
|
|
1237 |
<i><tt><array></tt></i> from the stack. As long as <i><tt><array></tt></i>
|
|
|
1238 |
is not contained in any readable dictionaries or elsewhere on stacks, it
|
|
|
1239 |
will not be accessible to <i><tt><procedure></tt></i>.
|
|
|
1240 |
<p>
|
|
|
1241 |
This operator is intended to allow hiding a <i><tt><save></tt></i> object
|
|
|
1242 |
during execution of procedures or files that run in <b>SAFER</b> mode.
|
|
|
1243 |
If a <b><tt>save</tt></b> is performed prior to entering <b>SAFER</b> mode
|
|
|
1244 |
with <b><tt>.setsafe</tt></b>, using the save object as the operand to
|
|
|
1245 |
<b><tt>restore</tt></b> will return to <b>NOSAFER</b> mode. In order to
|
|
|
1246 |
prevent the procedures running in <b>SAFER</b> mode from being able to
|
|
|
1247 |
return to <b>NOSAFER</b> mode, this operator should be used.
|
|
|
1248 |
Upon return from the file or procedure <b><tt>restore</tt></b> can be used
|
|
|
1249 |
to return to <b>NOSAFER</b> mode.
|
|
|
1250 |
<p>
|
|
|
1251 |
<b>Note:</b> The array operand hidden during the execution of the file or
|
|
|
1252 |
procedure will be placed at the top of the operand stack which may be on
|
|
|
1253 |
top of objects that the file or procedure leaves on top of the stack.
|
|
|
1254 |
Thus removing objects below the array may be needed to prevent an
|
|
|
1255 |
<b><tt>invalidrestore</tt></b> error.
|
|
|
1256 |
<p>
|
|
|
1257 |
For example, in order for a script or job server to execute a file
|
|
|
1258 |
<tt>somefile.ps</tt> with the <b>SAFER</b> mode restrictions in place, returning
|
|
|
1259 |
to unrestricted <b>NOSAFER</b> mode when the procedure exits is as follows:
|
|
|
1260 |
<pre>
|
|
|
1261 |
Start Ghostscript with <b>-dNOSAFER</b>
|
|
|
1262 |
|
|
|
1263 |
... % perform any device set up w/o restrictions
|
|
|
1264 |
[ save ] % create a save object before SAFER
|
|
|
1265 |
(somefile.ps) (r) file cvx % open the file to process
|
|
|
1266 |
.setsafe % enter SAFER mode
|
|
|
1267 |
.runandhide % run the file hiding the save object
|
|
|
1268 |
count 1 roll % place array below anything left over
|
|
|
1269 |
count 1 sub { pop } repeat % pop left over stuff
|
|
|
1270 |
cleardictstack % prevent invalidrestore from dicts
|
|
|
1271 |
|
|
|
1272 |
</pre>
|
|
|
1273 |
Another refinement on the above would be to execute <b><tt>.runandhide</tt></b>
|
|
|
1274 |
using <b><tt>stopped</tt></b> in order to report errors but continue processing.
|
|
|
1275 |
</dl>
|
|
|
1276 |
|
|
|
1277 |
<dl>
|
|
|
1278 |
<dt><b><tt>- .setsafe -</tt></b>
|
|
|
1279 |
<dd>If Ghostscript is started with <b><tt>-dNOSAFER</tt></b> or
|
|
|
1280 |
<b><tt>-dDELAYSAFER</tt></b>, this operator can be used to enter <b>SAFER</b>
|
|
|
1281 |
mode (see <a href="Use.htm#Safer"><b>-dSAFER</b></a>)
|
|
|
1282 |
<p>
|
|
|
1283 |
Since <b>SAFER</b> mode is implemented with userparameters and device parameters,
|
|
|
1284 |
it is possible to use <b><tt>save</tt></b> and <b><tt>restore</tt></b> before
|
|
|
1285 |
and after <b><tt>.setsafe</tt></b> to return to <b>NOSAFER</b> mode, but care
|
|
|
1286 |
should be taken to ensure that the <i><tt>save</tt></i> object is not
|
|
|
1287 |
accessible to any procedures or file run in <b>SAFER</b> mode (see
|
|
|
1288 |
<a href="#Runandhide"><b>.runandhide</b></a> above).
|
|
|
1289 |
<p>
|
|
|
1290 |
<b>Note: This uses setpagedevice to change .LockSafetyParams, so the page
|
|
|
1291 |
will be erased as a side effect of this operator</b>
|
|
|
1292 |
</dl>
|
|
|
1293 |
|
|
|
1294 |
<dl>
|
|
|
1295 |
<dt><b><tt>- .locksafe -</tt></b>
|
|
|
1296 |
<dd>
|
|
|
1297 |
This operator sets the current device's <b><tt>.LockSafetyParams</tt></b>
|
|
|
1298 |
and the <b><tt>LockFilePermissions</tt></b> userparameter true as well as
|
|
|
1299 |
adding the paths on LIBPATH and FONTPATH and the paths given by the
|
|
|
1300 |
system params /GenericResourceDir and /FontResourceDir to the current
|
|
|
1301 |
PermitFileReading list of paths.
|
|
|
1302 |
<p>
|
|
|
1303 |
If Ghostscript is started with <b><tt>-dNOSAFER</tt></b> or
|
|
|
1304 |
<b><tt>-dDELAYSAFER</tt></b>, this operator can be used to enter <b>SAFER</b>
|
|
|
1305 |
mode with the current set of <b><tt>PermitFile...</tt></b> user parameters
|
|
|
1306 |
in effect. Since <b><tt>.setsafe</tt></b> sets the <b><tt>PermitFile...</tt></b>
|
|
|
1307 |
user parameters to empty arrays, a script or job server that needs to
|
|
|
1308 |
enable certain paths for file Reading, Writing and/or Control can use this
|
|
|
1309 |
operator to perform the locking needed to enter <b>SAFER</b> mode.
|
|
|
1310 |
<p>
|
|
|
1311 |
For example, to enable reading everywhere, but disallow writing and file
|
|
|
1312 |
control (deleting and renaming files), the following can be used:
|
|
|
1313 |
<pre>
|
|
|
1314 |
{ << /PermitFileReading [ (*) ]
|
|
|
1315 |
/PermitFileWriting [ ]
|
|
|
1316 |
/PermitFileControl [ ]
|
|
|
1317 |
>> setuserparams
|
|
|
1318 |
.locksafe
|
|
|
1319 |
} stopped pop
|
|
|
1320 |
</pre>
|
|
|
1321 |
In the above example, use of stopped will allow the use of this sequence on
|
|
|
1322 |
older versions of Ghostscript where <b><tt>.locksafe</tt></b> was not an operator.
|
|
|
1323 |
<p>
|
|
|
1324 |
<b>Note: This uses setpagedevice to change .LockSafetyParams, so the page
|
|
|
1325 |
will be erased as a side effect of this operator</b>
|
|
|
1326 |
<p>
|
|
|
1327 |
See also <a href="#LockSafetyParams">.LockSafetyParams</a> and
|
|
|
1328 |
<a href="#User_parameters">User Parameters</a>.
|
|
|
1329 |
<p>
|
|
|
1330 |
</dl>
|
|
|
1331 |
|
|
|
1332 |
<dl><a name=".setpdfwrite"></a>
|
|
|
1333 |
<dt><b><tt>.setpdfwrite</tt></b></dt>
|
|
|
1334 |
<dd>This operator conditions the environment for the <tt>pdfwrite</tt> output device.
|
|
|
1335 |
It is a shorthand for setting parameters that have been deemed benificial. While not strictly necessary, it is usually helpful to set call this when using the pdfwrite device.
|
|
|
1336 |
For example, this is how the ps2pdf script calls Ghostscript:
|
|
|
1337 |
<blockquote><b><tt>
|
|
|
1338 |
gs -q -dSAFER -dNOPAUSE -dBATCH -sOutputFile=file.pdf </tt></b><em>[more options]</em><b><tt> \<br>
|
|
|
1339 |
-sDEVICE=pdfwrite -c .setpdfwrite -f </b></tt><em>source1.ps [more files]</em>
|
|
|
1340 |
</blockquote>
|
|
|
1341 |
<p>Currently, the operator just sets a minimum 3 MB vmthreshold to allow for
|
|
|
1342 |
accumulating shared object data and to reduce the incidence of garbage
|
|
|
1343 |
collection as a performance improvement. Additional settings may be added in the future.
|
|
|
1344 |
</dl>
|
|
|
1345 |
|
|
|
1346 |
<dl>
|
|
|
1347 |
<dt><b><tt>.color_test</tt></b> and <b><tt>.color_test_all</tt></b></dt>
|
|
|
1348 |
<dd>These operators are used for the verification of device encode_color and
|
|
|
1349 |
decode_color routines. They are for internal use only. Their function
|
|
|
1350 |
can, and probably will, change as Artifex's requirements change.
|
|
|
1351 |
<p>
|
|
|
1352 |
<dd>Currently these operators loop through a set of possible values for the inputs
|
|
|
1353 |
to the encode_color routine and then veify that the decode_color routines produce
|
|
|
1354 |
values that match the input set to within a tolerance which is based upon the number
|
|
|
1355 |
of bits used to encode a pixel. The operators also verify that if the device
|
|
|
1356 |
is 'separable' then that the values produced by gx_default_encode_color and
|
|
|
1357 |
gx_default_decode_color (the default encode/decode color handlers for a separable
|
|
|
1358 |
device) are consistent to within the same tolerance.
|
|
|
1359 |
</dl>
|
|
|
1360 |
|
|
|
1361 |
<h4><a name="Device"></a>Device operators</h4>
|
|
|
1362 |
|
|
|
1363 |
<dl>
|
|
|
1364 |
<dt><b><tt><device> copydevice <device></tt></b>
|
|
|
1365 |
<dd>Copies a device. The copy is writable and installable. The copy is
|
|
|
1366 |
created in the current VM (local or global), usually local VM for executing
|
|
|
1367 |
ordinary PostScript files.
|
|
|
1368 |
</dl>
|
|
|
1369 |
|
|
|
1370 |
<dl>
|
|
|
1371 |
<dt><b><tt><devicename> finddevice <device></tt></b>
|
|
|
1372 |
<dd>Creates a default instance of a device specified by name. The instance
|
|
|
1373 |
is created in global VM. If <b><tt>finddevice</tt></b> is called more than
|
|
|
1374 |
once with the same device name, it creates the default instance the first
|
|
|
1375 |
time, and returns the same instance thereafter.
|
|
|
1376 |
</dl>
|
|
|
1377 |
|
|
|
1378 |
<dl>
|
|
|
1379 |
<dt><b><tt><devicename> findprotodevice <device></tt></b>
|
|
|
1380 |
<dd>Finds the prototype of a device specified by name. A prototype can be
|
|
|
1381 |
used with <b><tt>.getdeviceparams</tt></b> or other parameter-reading
|
|
|
1382 |
operators, but it is read-only and cannot be set with
|
|
|
1383 |
<b><tt>setdevice</tt></b>: it must be copied first.
|
|
|
1384 |
</dl>
|
|
|
1385 |
|
|
|
1386 |
<dl>
|
|
|
1387 |
<dt><b><tt><device> <x> <y> <width> <max_height> <alpha?> <std_depth|null> <string> .getbitsrect <height> <substring></tt></b>
|
|
|
1388 |
<dd>Reads a rectangle of rendered bits back from a device. This is only
|
|
|
1389 |
guaranteed to be implemented for image devices (see below).
|
|
|
1390 |
<b><tt>alpha?</tt></b> is 0 for no alpha, -1 for alpha first, 1 for alpha
|
|
|
1391 |
last. <b><tt>std_depth</tt></b> is null for native pixels, number of bits
|
|
|
1392 |
per component for a standard color space.
|
|
|
1393 |
</dl>
|
|
|
1394 |
|
|
|
1395 |
<dl>
|
|
|
1396 |
<dt><b><tt><index> .getdevice <device></tt></b>
|
|
|
1397 |
<dd>Returns a device from the set of devices known to the system. The
|
|
|
1398 |
first device, which is the default, is numbered 0. If the
|
|
|
1399 |
<b><tt>index</tt></b> is out of range, causes a <b><tt>rangecheck</tt></b>
|
|
|
1400 |
error. This device is actually a prototype, not a directly usable device,
|
|
|
1401 |
and is marked read-only; it cannot have its parameters changed or be
|
|
|
1402 |
installed as the current device.
|
|
|
1403 |
</dl>
|
|
|
1404 |
|
|
|
1405 |
<dl>
|
|
|
1406 |
<dt><b><tt><matrix> <width> <height> <palette> makeimagedevice <device></tt></b>
|
|
|
1407 |
<dd>Makes a new device that accumulates an image in memory. <b><tt>
|
|
|
1408 |
matrix</tt></b> is the initial transformation matrix: it must be orthogonal
|
|
|
1409 |
(that is, [a 0 0 b x y] or
|
|
|
1410 |
[0 a b 0 x y]). <b><tt>palette</tt></b> is a
|
|
|
1411 |
string of 2^<small><sup><b>N</b></sup></small> or
|
|
|
1412 |
3 × 2^<small><sup><b>N</b></sup></small> elements,
|
|
|
1413 |
specifying how the 2^<small><sup><b>N</b></sup></small> possible pixel
|
|
|
1414 |
values will be interpreted. Each element is interpreted as a gray value,
|
|
|
1415 |
or as RGB values, multiplied by 255. For example, if you want a monochrome
|
|
|
1416 |
image for which 0=white and 1=black, the palette should be
|
|
|
1417 |
<b><tt><ff 00></tt></b>; if you want a 3-bit deep image with
|
|
|
1418 |
just the primary colors and their complements (ignoring the fact that 3-bit
|
|
|
1419 |
images are not supported), the palette might be <b><tt><000000 0000ff
|
|
|
1420 |
00ff00 00ffff ff0000 ff00ff ffff00 ffffff></tt></b>. At present, the
|
|
|
1421 |
palette must contain exactly 2, 4, 16, or 256 entries, and must contain an
|
|
|
1422 |
entry for black and an entry for white; if it contains any entries that
|
|
|
1423 |
aren't black, white, or gray, it must contain at least the six primary
|
|
|
1424 |
colors (red, green, blue, and their complements cyan, magenta, and yellow);
|
|
|
1425 |
aside from this, its contents are arbitrary.
|
|
|
1426 |
|
|
|
1427 |
<p>
|
|
|
1428 |
Alternatively, palette can be 16, 24, 32, or null (equivalent to 24).
|
|
|
1429 |
These are interpreted as:
|
|
|
1430 |
|
|
|
1431 |
<blockquote><table cellpadding=0 cellspacing=0>
|
|
|
1432 |
<tr valign=bottom>
|
|
|
1433 |
<th valign=bottom align=left>Palette
|
|
|
1434 |
<td>
|
|
|
1435 |
<th valign=bottom align=left>Bits allocated per color
|
|
|
1436 |
<tr> <td colspan=3><hr>
|
|
|
1437 |
<tr valign=top> <td>16
|
|
|
1438 |
<td>
|
|
|
1439 |
<td>5 red, 6 green, 5 blue
|
|
|
1440 |
<tr valign=top> <td>24
|
|
|
1441 |
<td>
|
|
|
1442 |
<td>8 red, 8 green, 8 blue
|
|
|
1443 |
<tr valign=top> <td>32
|
|
|
1444 |
<td>
|
|
|
1445 |
<td>8C, 8M, 8Y, 8K
|
|
|
1446 |
</table></blockquote>
|
|
|
1447 |
|
|
|
1448 |
<p>
|
|
|
1449 |
Note that one can also make an image device (with the same palette as an
|
|
|
1450 |
existing image device) by copying a device using the
|
|
|
1451 |
<b><tt>copydevice</tt></b> operator.
|
|
|
1452 |
</dl>
|
|
|
1453 |
|
|
|
1454 |
<dl>
|
|
|
1455 |
<dt><b><tt><matrix> <width> <height> <palette> <word?> makewordimagedevice <device></tt></b>
|
|
|
1456 |
<dd>Makes an image device as described above. <b><tt>word?</tt></b> is a
|
|
|
1457 |
Boolean value indicating whether the data should be stored in a
|
|
|
1458 |
word-oriented format internally. No ordinary PostScript programs should
|
|
|
1459 |
use this operator.
|
|
|
1460 |
</dl>
|
|
|
1461 |
|
|
|
1462 |
<dl>
|
|
|
1463 |
<dt><b><tt><device> <index> <string> copyscanlines <substring></tt></b>
|
|
|
1464 |
<dd>Copies one or more scan lines from an image device into a string,
|
|
|
1465 |
starting at a given scan line in the image. The data is in the same format
|
|
|
1466 |
as for the <b><tt>image</tt></b> operator. It is an error if the device is
|
|
|
1467 |
not an image device or if the string is too small to hold at least one
|
|
|
1468 |
complete scan line. Always copies an integral number of scan lines.
|
|
|
1469 |
</dl>
|
|
|
1470 |
|
|
|
1471 |
<dl>
|
|
|
1472 |
<dt><b><tt><device> setdevice -</tt></b>
|
|
|
1473 |
<dd>
|
|
|
1474 |
<p>
|
|
|
1475 |
Sets the current device to the specified device. Also resets the
|
|
|
1476 |
transformation and clipping path to the initial values for the device.
|
|
|
1477 |
Signals an <b><tt>invalidaccess</tt></b> error if the device is a
|
|
|
1478 |
prototype or if <a href="Language.htm#LockSafetyParams">.LockSafetyParams</a>
|
|
|
1479 |
is true for the current device.
|
|
|
1480 |
<p>
|
|
|
1481 |
Some device properties may need to be set with <tt>putdeviceprops</tt> before
|
|
|
1482 |
<b><tt>setdevice</tt></b> is called. For example, the pdfwrite device will try
|
|
|
1483 |
to open its output file, causing an <tt>undefinedfilename</tt> error if
|
|
|
1484 |
<tt>OutputFile</tt> hasn't been set to a valid filename. Another method in such
|
|
|
1485 |
cases is to use the level 2 operator instead:
|
|
|
1486 |
|
|
|
1487 |
<tt><< /OutputDevice /pdfwrite /OutputFile (MyPDF.pdf) >> <b>setpagedevice</b></tt>.
|
|
|
1488 |
|
|
|
1489 |
</dl>
|
|
|
1490 |
|
|
|
1491 |
<dl>
|
|
|
1492 |
<dt><b><tt>- currentdevice <device></tt></b>
|
|
|
1493 |
<dd>Gets the current device from the graphics state.
|
|
|
1494 |
</dl>
|
|
|
1495 |
|
|
|
1496 |
<dl>
|
|
|
1497 |
<dt><b><tt><device> getdeviceprops <mark> <name1> <value1> ... <namen> <valuen></tt></b>
|
|
|
1498 |
<dd>Gets the properties of a device. See the section on
|
|
|
1499 |
<a href="#Device_parameters">device parameters</a> below for details.
|
|
|
1500 |
</dl>
|
|
|
1501 |
|
|
|
1502 |
<dl>
|
|
|
1503 |
<dt><b><tt><mark> <name1> <value1> ... <namen> <valuen> <device> putdeviceprops <device></tt></b>
|
|
|
1504 |
<dd>Sets properties of a device. May cause <b><tt>undefined</tt></b>,
|
|
|
1505 |
<b><tt>invalidaccess</tt></b>, <b><tt>typecheck</tt></b>, <b><tt>rangecheck</tt></b>, or
|
|
|
1506 |
<b><tt>limitcheck</tt></b> errors.
|
|
|
1507 |
</dl>
|
|
|
1508 |
|
|
|
1509 |
<dl>
|
|
|
1510 |
<dt><b><tt>- flushpage -</tt></b>
|
|
|
1511 |
<dd>On displays, flushes any buffered output, so that it is guaranteed to
|
|
|
1512 |
show up on the screen; on printers, has no effect.
|
|
|
1513 |
</dl>
|
|
|
1514 |
|
|
|
1515 |
<hr>
|
|
|
1516 |
|
|
|
1517 |
<h2><a name="Filters"></a>Filters</h2>
|
|
|
1518 |
|
|
|
1519 |
<h3><a name="Standard_filters"></a>Standard filters</h3>
|
|
|
1520 |
|
|
|
1521 |
<p>
|
|
|
1522 |
In its usual configuration, Ghostscript supports all the standard PostScript
|
|
|
1523 |
LanguageLevel 3 filters, both encoding and decoding, except that it does not
|
|
|
1524 |
currently support:
|
|
|
1525 |
|
|
|
1526 |
<ul>
|
|
|
1527 |
|
|
|
1528 |
<li>the <b><tt>EarlyChange</tt></b> key in the <b><tt>LZWEncode</tt></b>
|
|
|
1529 |
filter.
|
|
|
1530 |
|
|
|
1531 |
</ul>
|
|
|
1532 |
|
|
|
1533 |
<p>
|
|
|
1534 |
Ghostscript also supports additional keys in the optional dictionary
|
|
|
1535 |
operands for some filters. For the <b><tt>LZWDecode</tt></b> filter:
|
|
|
1536 |
|
|
|
1537 |
<dl>
|
|
|
1538 |
<dt><b><tt>InitialCodeLength <integer></tt></b> (default 8)
|
|
|
1539 |
<dd>An integer between 2 and 11 specifying the initial number of data bits
|
|
|
1540 |
per code. Note that the actual initial code length is 1 greater than this,
|
|
|
1541 |
to allow for the reset and end-of-data code values.
|
|
|
1542 |
</dl>
|
|
|
1543 |
|
|
|
1544 |
<dl>
|
|
|
1545 |
<dt><b><tt>FirstBitLowOrder <boolean></tt></b> (default false)
|
|
|
1546 |
<dd>If true, codes appear with their low-order bit first.
|
|
|
1547 |
</dl>
|
|
|
1548 |
|
|
|
1549 |
<dl>
|
|
|
1550 |
<dt><b><tt>BlockData <boolean></tt></b> (default false)
|
|
|
1551 |
<dd>If true, the data is broken into blocks in the manner specified for the
|
|
|
1552 |
GIF file format.
|
|
|
1553 |
</dl>
|
|
|
1554 |
|
|
|
1555 |
<p>
|
|
|
1556 |
For the <b><tt>CCITTFaxEncode</tt></b> and <b><tt>CCITTFaxDecode</tt></b>
|
|
|
1557 |
filters:
|
|
|
1558 |
|
|
|
1559 |
<dl>
|
|
|
1560 |
<dt><b><tt>DecodedByteAlign <integer></tt></b> (default 1)
|
|
|
1561 |
<dd>An integer <b>N</b> with the value 1, 2, 4, 8, or 16, specifying that
|
|
|
1562 |
decoded data scan lines are always a multiple of <b>N</b> bytes. The
|
|
|
1563 |
encoding filter skips data in each scan line from Columns to the next
|
|
|
1564 |
multiple of <b>N</b> bytes; the decoding filter pads each scan line to a
|
|
|
1565 |
multiple of <b>N</b> bytes.
|
|
|
1566 |
</dl>
|
|
|
1567 |
|
|
|
1568 |
<h3><a name="Non_standard_filters"></a>Non-standard filters</h3>
|
|
|
1569 |
|
|
|
1570 |
<p>
|
|
|
1571 |
In addition to the standard PostScript LanguageLevel 3 filters, Ghostscript
|
|
|
1572 |
supports the following non-standard filters. Many of these filters are used
|
|
|
1573 |
internally to implement standard filters or facilities; they are almost
|
|
|
1574 |
certain to remain, in their present form or a backward-compatible one, in
|
|
|
1575 |
future Ghostscript releases.
|
|
|
1576 |
|
|
|
1577 |
<dl>
|
|
|
1578 |
<dt><b><tt><target> /BCPEncode filter <file></tt></b>
|
|
|
1579 |
<dt><b><tt><source> /BCPDecode filter <file></tt></b>
|
|
|
1580 |
<dd>Create filters that implement the Adobe Binary Communications Protocol.
|
|
|
1581 |
See Adobe documentation for details.
|
|
|
1582 |
</dl>
|
|
|
1583 |
|
|
|
1584 |
<dl>
|
|
|
1585 |
<dt><b><tt><target> <seed_integer> /eexecEncode filter <file></tt></b>
|
|
|
1586 |
<dd>Creates a filter for encrypting data into the encrypted format described
|
|
|
1587 |
in the Adobe Type 1 Font Format documentation. The
|
|
|
1588 |
<b><tt>seed_integer</tt></b> must be 55665 for the <b><tt>eexec</tt></b>
|
|
|
1589 |
section of a font, or 4330 for a <b><tt>CharString</tt></b>. Note that for
|
|
|
1590 |
the <b><tt>eexec</tt></b> section of a font, this filter produces binary
|
|
|
1591 |
output and does not include the initial 4 (or <b><tt>lenIV</tt></b>) garbage
|
|
|
1592 |
bytes.
|
|
|
1593 |
</dl>
|
|
|
1594 |
|
|
|
1595 |
<dl>
|
|
|
1596 |
<dt><b><tt><source> <seed_integer> /eexecDecode filter <file></tt></b>
|
|
|
1597 |
<dt><b><tt><source> <dict> /eexecDecode filter <file></tt></b>
|
|
|
1598 |
<dd>Creates a filter for decrypting data encrypted as described in the Adobe
|
|
|
1599 |
Type 1 Font Format documentation. The <b><tt>seed_integer</tt></b> must be
|
|
|
1600 |
55665 or 4330 as described just above. Recognized dictionary keys are:
|
|
|
1601 |
|
|
|
1602 |
<blockquote>
|
|
|
1603 |
<b><tt>seed <16-bit integer></tt></b> (required)<br>
|
|
|
1604 |
<b><tt>lenIV <non-negative integer></tt></b> (default=4)<br>
|
|
|
1605 |
<b><tt>eexec <bool></tt></b> (default=<b><tt>false</b></tt>)
|
|
|
1606 |
</blockquote>
|
|
|
1607 |
</dl>
|
|
|
1608 |
|
|
|
1609 |
<dl>
|
|
|
1610 |
<dt><b><tt><target> /MD5Encode filter <file></tt></b>
|
|
|
1611 |
<dd>Creates a filter that produces the 16-byte MD5 digest of the input.
|
|
|
1612 |
Note that no output is produced until the filter is closed.
|
|
|
1613 |
</dl>
|
|
|
1614 |
|
|
|
1615 |
<dl>
|
|
|
1616 |
<dt><b><tt><source> <hex_boolean> /PFBDecode filter <file></tt></b>
|
|
|
1617 |
<dd>Creates a filter that decodes data in <b><tt>.PFB</tt></b> format, the
|
|
|
1618 |
usual semi-binary representation for Type 1 font files on IBM PC and
|
|
|
1619 |
compatible systems. If <b><tt>hex_boolean</tt></b> is true, binary packets
|
|
|
1620 |
are converted to hex; if false, binary packets are not converted.
|
|
|
1621 |
</dl>
|
|
|
1622 |
|
|
|
1623 |
<dl>
|
|
|
1624 |
<dt><b><tt><target> <dict> /PixelDifferenceEncode filter <file></tt></b>
|
|
|
1625 |
<dt><b><tt><source> <dict> /PixelDifferenceDecode filter <file></tt></b>
|
|
|
1626 |
<dd>Implements the Predictor=2 pixel-differencing option of the LZW
|
|
|
1627 |
filters. Recognized keys are:
|
|
|
1628 |
|
|
|
1629 |
<blockquote>
|
|
|
1630 |
<b><tt>Colors <integer></tt></b> (1 to 4, default=1)<br>
|
|
|
1631 |
<b><tt>BitsPerComponent <integer></tt></b> (1, 2, 4, or 8, default=8)<br>
|
|
|
1632 |
<b><tt>Columns <integer></tt></b> (>= 0, required)
|
|
|
1633 |
</blockquote>
|
|
|
1634 |
|
|
|
1635 |
<p>
|
|
|
1636 |
See the Adobe <a
|
|
|
1637 |
href="http://partners.adobe.com/asn/developer/acrosdk/DOCS/pdfspec.pdf"><em>Portable
|
|
|
1638 |
Document Format Reference Manual</em></a> for details.
|
|
|
1639 |
</dl>
|
|
|
1640 |
|
|
|
1641 |
<dl>
|
|
|
1642 |
<dt><b><tt><target> <dict> /PNGPredictorEncode filter <file></tt></b>
|
|
|
1643 |
<dt><b><tt><source> <dict> /PNGPredictorDecode filter <file></tt></b>
|
|
|
1644 |
<dd>Implements the "filter" algorithms of the
|
|
|
1645 |
<a href="http://www.libpng.org/pub/png/">Portable Network Graphics (PNG)
|
|
|
1646 |
graphics format</a>. Recognized keys are:
|
|
|
1647 |
|
|
|
1648 |
<blockquote><table cellpadding=0 cellspacing=0>
|
|
|
1649 |
<tr><th colspan=5 bgcolor="#CCCC00"><hr><font size="+1">Keys recognized in PNG filter algorithms</font><hr>
|
|
|
1650 |
<tr valign=bottom>
|
|
|
1651 |
<th align=left>Key
|
|
|
1652 |
<td>
|
|
|
1653 |
<th align=left>Range
|
|
|
1654 |
<td>
|
|
|
1655 |
<th align=left>Default
|
|
|
1656 |
<tr> <td colspan=5><hr>
|
|
|
1657 |
<tr valign=top> <td><b><tt>Colors <integer></tt></b>
|
|
|
1658 |
<td>
|
|
|
1659 |
<td>1 to 16
|
|
|
1660 |
<td>
|
|
|
1661 |
<td>16
|
|
|
1662 |
<tr valign=top> <td><b><tt>BitsPerComponent <integer></tt></b>
|
|
|
1663 |
<td>
|
|
|
1664 |
<td>1, 2, 4, 8, or 16
|
|
|
1665 |
<td>
|
|
|
1666 |
<td>8
|
|
|
1667 |
<tr valign=top> <td><b><tt>Columns <integer></tt></b>
|
|
|
1668 |
<td>
|
|
|
1669 |
<td>>= 0
|
|
|
1670 |
<td>
|
|
|
1671 |
<td>1
|
|
|
1672 |
<tr valign=top> <td><b><tt>Predictor <integer></tt></b>
|
|
|
1673 |
<td>
|
|
|
1674 |
<td>10 to 15
|
|
|
1675 |
<td>
|
|
|
1676 |
<td>15
|
|
|
1677 |
</table></blockquote>
|
|
|
1678 |
|
|
|
1679 |
<p>
|
|
|
1680 |
The <b><tt>Predictor</tt></b> is the PNG algorithm number + 10 for the
|
|
|
1681 |
<b><tt>Encoding</tt></b> filter; the <b><tt>Decoding</tt></b> filter
|
|
|
1682 |
ignores <b><tt>Predictor</tt></b>. 15 means the encoder attempts to
|
|
|
1683 |
optimize the choice of algorithm. For more details see the PNG
|
|
|
1684 |
specification
|
|
|
1685 |
|
|
|
1686 |
<blockquote>
|
|
|
1687 |
<a href="http://www.w3.org/TR/WD-png-960128.html">http://www.w3.org/TR/WD-png-960128.html</a>
|
|
|
1688 |
</blockquote>
|
|
|
1689 |
</dl>
|
|
|
1690 |
|
|
|
1691 |
<dl>
|
|
|
1692 |
<dt><b><tt><target> /TBCPEncode filter <file></tt></b>
|
|
|
1693 |
<dt><b><tt><source> /TBCPDecode filter <file></tt></b>
|
|
|
1694 |
<dd>Create filters that implement the Adobe Tagged Binary Communications
|
|
|
1695 |
Protocol. See Adobe documentation for details.
|
|
|
1696 |
</dl>
|
|
|
1697 |
|
|
|
1698 |
<dl>
|
|
|
1699 |
<dt><b><tt><target> /zlibEncode filter <file></tt></b>
|
|
|
1700 |
<dt><b><tt><source> /zlibDecode filter <file></tt></b>
|
|
|
1701 |
<dd>Creates filters that use the data compression method variously known as
|
|
|
1702 |
'zlib' (the name of a popular library that implements it), 'Deflate' (as in
|
|
|
1703 |
<a href="http://www.ietf.org/rfc/rfc1951.txt">RFC 1951</a>, which is a
|
|
|
1704 |
detailed specification for the method), 'gzip' (the name of a popular
|
|
|
1705 |
compression application that uses it), or 'Flate' (Adobe's name). Note that
|
|
|
1706 |
the PostScript <b><tt>Flate</tt></b> filters are actually a combination of
|
|
|
1707 |
this filter with an optional predictor filter.
|
|
|
1708 |
</dl>
|
|
|
1709 |
|
|
|
1710 |
<h3><a name="Unstable_filters"></a>Unstable filters</h3>
|
|
|
1711 |
|
|
|
1712 |
<p>
|
|
|
1713 |
Some versions of Ghostscript may also support other non-standard filters for
|
|
|
1714 |
experimental purposes. The current version includes the following such
|
|
|
1715 |
filters, which are not documented further. No code should assume that these
|
|
|
1716 |
filters will exist in compatible form, or at all, in future versions.
|
|
|
1717 |
|
|
|
1718 |
<dl>
|
|
|
1719 |
<dt><b><tt><target/source> <string> ByteTranslateEncode/Decode filter <file></tt></b>
|
|
|
1720 |
<dd><b><tt>string</tt></b> must be a string of exactly 256 bytes. Creates a
|
|
|
1721 |
filter that converts each input byte <em>b</em> to
|
|
|
1722 |
<b><tt>string</tt></b>[<em>b</em>]. Note that the <b><tt>Encode</tt></b>
|
|
|
1723 |
and <b><tt>Decode</tt></b> filters operate identically: the client must
|
|
|
1724 |
provide a <b><tt>string</tt></b> for the <b><tt>Decode</tt></b> filter that
|
|
|
1725 |
is the inverse mapping of the <b><tt>string</tt></b> for the
|
|
|
1726 |
<b><tt>Encode</tt></b> filter.
|
|
|
1727 |
</dl>
|
|
|
1728 |
|
|
|
1729 |
<dl>
|
|
|
1730 |
<dt><b><tt><target/source> <dict> BoundedHuffmanEncode/Decode filter <file></tt></b>
|
|
|
1731 |
<dd>These filters encode and decode data using Huffman codes. Since these
|
|
|
1732 |
filters aren't used anywhere, we don't document them further, except to note
|
|
|
1733 |
the recognized dictionary keys, which must be set identically for encoding
|
|
|
1734 |
and decoding:
|
|
|
1735 |
|
|
|
1736 |
<blockquote>
|
|
|
1737 |
<b><tt>FirstBitLowOrder <bool></tt></b> (default=false)<br>
|
|
|
1738 |
<b><tt>MaxCodeLength <int></tt></b> (default=16)<br>
|
|
|
1739 |
<b><tt>EndOfData <bool></tt></b> (default=true)<br>
|
|
|
1740 |
<b><tt>EncodeZeroRuns <int></tt></b> (default=256)<br>
|
|
|
1741 |
<b><tt>Tables <int_array></tt></b>
|
|
|
1742 |
</blockquote>
|
|
|
1743 |
</dl>
|
|
|
1744 |
|
|
|
1745 |
<dl>
|
|
|
1746 |
<dt><b><tt><target/source> <dict> BWBlockSortEncode/Decode filter <file></tt></b>
|
|
|
1747 |
<dd>This filter implements the Burroughs-Wheeler block sorting compression
|
|
|
1748 |
method, which we've heard is also used in the popular <b><tt>bzip2</tt></b>
|
|
|
1749 |
compression application. See <a
|
|
|
1750 |
href="http://sources.redhat.com/bzip2/">http://sources.redhat.com/bzip2/</a>
|
|
|
1751 |
for more information. The only recognized dictionary key is:
|
|
|
1752 |
|
|
|
1753 |
<blockquote>
|
|
|
1754 |
<b><tt>BlockSize <integer></tt></b> (default=16384)
|
|
|
1755 |
</blockquote>
|
|
|
1756 |
</dl>
|
|
|
1757 |
|
|
|
1758 |
<dl>
|
|
|
1759 |
<dt><b><tt><target/source> MoveToFrontEncode/Decode filter <file></tt></b>
|
|
|
1760 |
|
|
|
1761 |
<dd>The <b><tt>Encode</tt></b> filter starts by initializing an internal
|
|
|
1762 |
256-byte array <b><tt>a</tt></b> to the values 0 .. 255. This array will
|
|
|
1763 |
always hold a permutation of these values. Then for each input byte
|
|
|
1764 |
<em>b</em>, the filter outputs the index <em>i</em> such that
|
|
|
1765 |
<b><tt>a</tt></b>[<em>i</em>] = <em>b</em>, and moves that element to the
|
|
|
1766 |
front (element 0) of <b><tt>a</tt></b>, moving elements 0 .. <em>i-1</em> to
|
|
|
1767 |
positions 1 .. <em>i</em>. The <b><tt>Decode</tt></b> filter inverts this
|
|
|
1768 |
process.
|
|
|
1769 |
</dl>
|
|
|
1770 |
|
|
|
1771 |
<hr>
|
|
|
1772 |
|
|
|
1773 |
<h2><a name="Device_parameters"></a>Device parameters</h2>
|
|
|
1774 |
|
|
|
1775 |
Ghostscript supports the concept of device parameters for all devices, not
|
|
|
1776 |
just page devices. (For non-page devices, these are accessible through
|
|
|
1777 |
<b><tt>getdeviceprops</tt></b> and <b><tt>putdeviceprops</tt></b>, as
|
|
|
1778 |
indicated above.) Here are the currently defined parameters for all
|
|
|
1779 |
devices:
|
|
|
1780 |
|
|
|
1781 |
<dl>
|
|
|
1782 |
<a name="LockSafetyParams"></a>
|
|
|
1783 |
<dt><b><tt>.LockSafetyParams <boolean></tt></b>
|
|
|
1784 |
<dd>This parameter allows for improved system security by preventing
|
|
|
1785 |
PostScript programs from being able to change potentially dangerous
|
|
|
1786 |
device paramters such as OutputFile. This parameter cannot be set false
|
|
|
1787 |
if it is already true.
|
|
|
1788 |
<p>
|
|
|
1789 |
If this parameter is true for the current device, attempt to set a new
|
|
|
1790 |
device that has <b><tt>.LockSafetyParams</tt></b> false will signal an
|
|
|
1791 |
<tt><b> invalidaccess</b></tt> error.
|
|
|
1792 |
</dl>
|
|
|
1793 |
|
|
|
1794 |
<dl>
|
|
|
1795 |
<dt><b><tt>BitsPerPixel <integer> (usually read-only)</tt></b>
|
|
|
1796 |
<dd>Number of bits per pixel.
|
|
|
1797 |
</dl>
|
|
|
1798 |
|
|
|
1799 |
<dl>
|
|
|
1800 |
<dt><b><tt>.HWMargins [<four floats>]</tt></b>
|
|
|
1801 |
<dd>Size of non-imageable regions around the edges of the page, in points
|
|
|
1802 |
(units of 1/72in; see the <a href="Devices.htm#Measurements">notes on
|
|
|
1803 |
measurements</a> in the documentation on devices).
|
|
|
1804 |
</dl>
|
|
|
1805 |
|
|
|
1806 |
<dl>
|
|
|
1807 |
<dt><b><tt>HWSize [<integer> <integer>]</tt></b>
|
|
|
1808 |
<dd>X and Y size in pixels.
|
|
|
1809 |
</dl>
|
|
|
1810 |
|
|
|
1811 |
<dl>
|
|
|
1812 |
<dt><b><tt>Name <string> (read-only)</tt></b>
|
|
|
1813 |
<dd>The device name. Currently the same as <b><tt>OutputDevice</tt></b>.
|
|
|
1814 |
</dl>
|
|
|
1815 |
|
|
|
1816 |
<dl>
|
|
|
1817 |
<dt><b><tt>Colors, GrayValues, RedValues, GreenValues, BlueValues, ColorValues (usually read-only)</tt></b>
|
|
|
1818 |
<dd>As for the <b><tt>deviceinfo</tt></b> operator of Display PostScript.
|
|
|
1819 |
<b><tt>Red</tt></b>, <b><tt>Green</tt></b>, <b><tt>Blue</tt></b>, and
|
|
|
1820 |
<b><tt>ColorValues</tt></b> are only defined if
|
|
|
1821 |
<b><tt>Colors</tt></b> > 1.
|
|
|
1822 |
</dl>
|
|
|
1823 |
|
|
|
1824 |
<dl>
|
|
|
1825 |
<dt><b><tt>TextAlphaBits, GraphicsAlphaBits (usually read-only)</tt></b>
|
|
|
1826 |
<dd>The number of bits of anti-aliasing information for text or graphics
|
|
|
1827 |
respectively. Legal values are 1 (no anti-aliasing, the default for most
|
|
|
1828 |
devices), 2, or 4.
|
|
|
1829 |
</dl>
|
|
|
1830 |
|
|
|
1831 |
<p>
|
|
|
1832 |
Ghostscript also supports the following read-only parameter that is not a
|
|
|
1833 |
true device parameter:
|
|
|
1834 |
|
|
|
1835 |
<dl>
|
|
|
1836 |
<dt><b><tt>.EmbedFontObjects <integer></tt></b>
|
|
|
1837 |
<dd>If non-zero, indicates that the device may embed font objects (as
|
|
|
1838 |
opposed to bitmaps for individual characters) in the output. The purpose of
|
|
|
1839 |
this parameter is to disable third-party font renderers for such devices.
|
|
|
1840 |
(This is zero for almost all devices.)
|
|
|
1841 |
</dl>
|
|
|
1842 |
|
|
|
1843 |
<p>
|
|
|
1844 |
In addition, the following are defined per Adobe's documentation for the
|
|
|
1845 |
<b><tt>setpagedevice</tt></b> operator:
|
|
|
1846 |
|
|
|
1847 |
<blockquote>
|
|
|
1848 |
<b><tt>Duplex</tt></b> (if supported)<br>
|
|
|
1849 |
<b><tt>HWResolution</tt></b><br>
|
|
|
1850 |
<b><tt>ImagingBBox</tt></b><br>
|
|
|
1851 |
<b><tt>Margins</tt></b><br>
|
|
|
1852 |
<b><tt>NumCopies</tt></b> (for printers only)<br>
|
|
|
1853 |
<b><tt>Orientation</tt></b> (if supported)<br>
|
|
|
1854 |
<b><tt>OutputDevice</tt></b><br>
|
|
|
1855 |
<b><tt>PageOffset</tt></b> (write-only)<br>
|
|
|
1856 |
<b><tt>PageSize</tt></b><br>
|
|
|
1857 |
<b><tt>ProcessColorModel</tt></b> (usually read-only)<br>
|
|
|
1858 |
</blockquote>
|
|
|
1859 |
|
|
|
1860 |
<p>
|
|
|
1861 |
Some devices may only allow certain values for <b><tt>HWResolution</tt></b>
|
|
|
1862 |
and <b><tt>PageSize</tt></b>. The null device ignores attempts to set
|
|
|
1863 |
<b><tt>PageSize</tt></b>; its size is always <b><tt>[0 0]</tt></b>.
|
|
|
1864 |
|
|
|
1865 |
<p>
|
|
|
1866 |
It should be noted that calling <tt>setpagedevice</tt> with one of the above keys may reset the effects of any <b><tt>pdfmark</tt></b> commands up to that point. In particular this is true of HWResolution, a behavior that differs from Adobe Distiller.
|
|
|
1867 |
|
|
|
1868 |
<p>
|
|
|
1869 |
For printers these are also defined:
|
|
|
1870 |
|
|
|
1871 |
<dl>
|
|
|
1872 |
<dt><b><tt>BufferSpace <integer></tt></b>
|
|
|
1873 |
<dd>Buffer space for band lists, if the bitmap is too big to fit in memory.
|
|
|
1874 |
</dl>
|
|
|
1875 |
|
|
|
1876 |
<dl>
|
|
|
1877 |
<dt><b><tt>MaxBitmap <integer></tt></b>
|
|
|
1878 |
<dd>Maximum space for a full bitmap in memory.
|
|
|
1879 |
</dl>
|
|
|
1880 |
|
|
|
1881 |
<dl>
|
|
|
1882 |
<dt><b><tt>OutputFile <string></tt></b>
|
|
|
1883 |
|
|
|
1884 |
<dd>An empty string means "send to printer directly", otherwise specifies
|
|
|
1885 |
the file name for output; <b><tt>%d</tt></b> is replaced by the page number
|
|
|
1886 |
for page-oriented output devices;
|
|
|
1887 |
on Unix systems <b><tt>%pipe%</tt></b><em>command</em> writes to a pipe.
|
|
|
1888 |
(<b><tt>|</tt></b><em>command</em> also writes to a pipe, but is now
|
|
|
1889 |
deprecated.)
|
|
|
1890 |
<p>
|
|
|
1891 |
Attempts to set this parameter if <tt><b>.LockSafetyParams</b></tt> is true
|
|
|
1892 |
will signal an <tt><b>invalidaccess</b></tt> error.
|
|
|
1893 |
</dl>
|
|
|
1894 |
|
|
|
1895 |
<dl>
|
|
|
1896 |
<dt><b><tt>OpenOutputFile <boolean></tt></b>
|
|
|
1897 |
<dd>If true, open the device's output file when the device is opened,
|
|
|
1898 |
rather than waiting until the first page is ready to print.
|
|
|
1899 |
</dl>
|
|
|
1900 |
|
|
|
1901 |
<dl>
|
|
|
1902 |
<dt><b><tt>PageCount <integer> (read-only)</tt></b>
|
|
|
1903 |
<dd>Counts the number of pages printed on the device.
|
|
|
1904 |
</dl>
|
|
|
1905 |
|
|
|
1906 |
<p>
|
|
|
1907 |
The following parameters are for use only by very specialized applications
|
|
|
1908 |
that separate band construction from band rasterization. Improper use may
|
|
|
1909 |
cause unpredictable errors. In particular, if you only want to allocate
|
|
|
1910 |
more memory for banding, to increase band size and improve performance, use
|
|
|
1911 |
the <b><tt>BufferSpace</tt></b> parameter, not
|
|
|
1912 |
<b><tt>BandBufferSpace</tt></b>.
|
|
|
1913 |
|
|
|
1914 |
<dl>
|
|
|
1915 |
<dt><b><tt>BandHeight <integer></tt></b>
|
|
|
1916 |
<dd>The height of bands when banding. 0 means use the largest band height
|
|
|
1917 |
that will fit within the BandBufferSpace (or BufferSpace, if
|
|
|
1918 |
BandBufferSpace is not specified).
|
|
|
1919 |
</dl>
|
|
|
1920 |
|
|
|
1921 |
<dl>
|
|
|
1922 |
<dt><b><tt>BandWidth <integer></tt></b>
|
|
|
1923 |
<dd>The width of bands in the rasterizing pass, in pixels. 0 means use the
|
|
|
1924 |
actual page width.
|
|
|
1925 |
</dl>
|
|
|
1926 |
|
|
|
1927 |
<dl>
|
|
|
1928 |
<dt><b><tt>BandBufferSpace <integer></tt></b>
|
|
|
1929 |
<dd>The size of the band buffer in the rasterizing pass, in bytes. 0 means
|
|
|
1930 |
use the same buffer size as for the interpretation pass.
|
|
|
1931 |
</dl>
|
|
|
1932 |
|
|
|
1933 |
<p>
|
|
|
1934 |
Ghostscript supports the following parameter for
|
|
|
1935 |
<b><tt>setpagedevice</tt></b> and <b><tt>currentpagedevice</tt></b> that is
|
|
|
1936 |
not a device parameter per se:
|
|
|
1937 |
|
|
|
1938 |
<dl>
|
|
|
1939 |
<dt><b><tt>ViewerPreProcess <procedure></tt></b>
|
|
|
1940 |
<dd>Specifies a procedure to be applied to the page device dictionary
|
|
|
1941 |
before any other processing is done. The procedure may not alter the
|
|
|
1942 |
dictionary, but it may return a modified copy. This "hook" is provided for
|
|
|
1943 |
use by viewing programs such as GSview.
|
|
|
1944 |
</dl>
|
|
|
1945 |
|
|
|
1946 |
<hr>
|
|
|
1947 |
|
|
|
1948 |
<h2><a name="User_parameters"></a>User parameters</h2>
|
|
|
1949 |
|
|
|
1950 |
Ghostscript supports the following non-standard user parameters:
|
|
|
1951 |
|
|
|
1952 |
<dl>
|
|
|
1953 |
<dt><b><tt>ProcessDSCComment <procedure|null></tt></b>
|
|
|
1954 |
<dd>If not null, this procedure is called whenever the scanner detects a DSC
|
|
|
1955 |
comment (comment beginning with <b><tt>%%</tt></b> or <b><tt>%!</tt></b>).
|
|
|
1956 |
There are two operands, the file and the comment (minus any terminating
|
|
|
1957 |
EOL), which the procedure must consume.
|
|
|
1958 |
</dl>
|
|
|
1959 |
|
|
|
1960 |
<dl>
|
|
|
1961 |
<dt><b><tt>ProcessComment <procedure|null></tt></b>
|
|
|
1962 |
<dd>If not null, this procedure is called whenever the scanner detects a
|
|
|
1963 |
comment (or, if <b><tt>ProcessDSCComment</tt></b> is also not null, a
|
|
|
1964 |
comment other than a DSC comment). The operands are the same as for
|
|
|
1965 |
<b><tt>ProcessDSCComment</tt></b>.
|
|
|
1966 |
</dl>
|
|
|
1967 |
|
|
|
1968 |
<dl>
|
|
|
1969 |
<dt><b><tt>LockFilePermissions <boolean></tt></b>
|
|
|
1970 |
<dd>If <tt>true</tt>, this parameter and the three <tt>PermitFile...</tt>
|
|
|
1971 |
parameters cannot be changed. Attempts to change any of the values
|
|
|
1972 |
when LockFilePermissions is <tt>true</tt> will signal <b><tt>invalidaccess</tt></b>.
|
|
|
1973 |
Also, when this value is <tt>true</tt>, the <b><tt>file</tt></b> operator
|
|
|
1974 |
will give <b><tt>invalidaccess</tt></b> when attempting to open files
|
|
|
1975 |
(processes) using the <b><tt>%pipe</tt></b> device.
|
|
|
1976 |
<p>
|
|
|
1977 |
Also when <b><tt>LockFilePermissions</tt></b> is <tt>true</tt>, strings
|
|
|
1978 |
cannot reference the parent directory (platform specific). For example
|
|
|
1979 |
<b><tt>(../../xyz)</tt></b> is illegal on unix, Windows
|
|
|
1980 |
and Macintosh, and <b><tt>([.#.#.XYZ])</tt></b> is illegal on VMS.
|
|
|
1981 |
<p>
|
|
|
1982 |
This parameter is set <tt>true</tt> by the <b><tt>.setsafe</tt></b> and
|
|
|
1983 |
<b><tt>.locksafe</tt></b> operators.
|
|
|
1984 |
</dl>
|
|
|
1985 |
|
|
|
1986 |
<dl>
|
|
|
1987 |
<dt><b><tt>PermitFileReading <array of strings></tt></b>
|
|
|
1988 |
<dt><b><tt>PermitFileWriting <array of strings></tt></b>
|
|
|
1989 |
<dt><b><tt>PermitFileControl <array of strings></tt></b>
|
|
|
1990 |
<dd>These parameters specify paths where file reading, writing and the
|
|
|
1991 |
'control' operations are permitted, respectively. File control
|
|
|
1992 |
operations are <b><tt>deletefile</tt></b> and <b><tt>renamefile</tt></b>.
|
|
|
1993 |
For <b><tt>renamefile</tt></b>, the filename for the current filename
|
|
|
1994 |
must match one of the paths on the PermitFileControl list, and the
|
|
|
1995 |
new filename must be on <b>both</b> the PermitFileControl and the
|
|
|
1996 |
PermitFileWriting lists of paths.
|
|
|
1997 |
<p>
|
|
|
1998 |
The strings can contain wildcard characters as for the <b><tt>filenameforall</tt></b>
|
|
|
1999 |
operator and unless specifying a single file, will end with a <b>*</b>
|
|
|
2000 |
for directories (folders) to allow access to all files and sub-directories
|
|
|
2001 |
in that directory.
|
|
|
2002 |
<p>
|
|
|
2003 |
<b>Note:</b> The strings are used for stringmatch operations similar
|
|
|
2004 |
to <b><tt>filenameforall</tt></b>, thus on MS Windows platforms, use the '/'
|
|
|
2005 |
character to separate directories and filenames or use '\\\\' to
|
|
|
2006 |
have the string contain '\\' which will match a single '\' in the
|
|
|
2007 |
target filename (use of '/' is strongly recommended).
|
|
|
2008 |
<p>
|
|
|
2009 |
The <a href=Use.htm#Safer><b>SAFER</b></a> mode and the
|
|
|
2010 |
<b><tt>.setsafe</tt></b> operator set all three lists to empty arrays,
|
|
|
2011 |
thus the only files that can be read are the <b><tt>%stdin</tt></b> device and
|
|
|
2012 |
on LIBPATH or FONTPATH or the Resource paths specified by the /FontResourceDir
|
|
|
2013 |
or /GenericResourceDir system params. Files cannot be opened for writing
|
|
|
2014 |
anywhere and cannot be deleted or renamed except for files created with the
|
|
|
2015 |
<a href=#Tempfile><b>.tempfile</b></a> operator).
|
|
|
2016 |
<p>
|
|
|
2017 |
<b>Note: </b>Limiting file reading as above is <b>NOT</b> compatible with
|
|
|
2018 |
SAFER mode in release versions before 7.11 and corresponds to the use of
|
|
|
2019 |
<b><tt>-dPARANOIDSAFER</tt></b> in version 7.04 (up to and not including
|
|
|
2020 |
version 7.10) and GPL versions 6.53 (up to and not including 6.60).
|
|
|
2021 |
</dl>
|
|
|
2022 |
|
|
|
2023 |
<dl>
|
|
|
2024 |
<dt><b><tt>AlignToPixels <integer></tt></b>
|
|
|
2025 |
<dd>Control sub-pixel positioning of character glyphs (where
|
|
|
2026 |
applicable). A value of 1 specifies alignment of text characters to
|
|
|
2027 |
pixels boundaries. A value of 0 to subpixels where the division factor
|
|
|
2028 |
is set by the device parameter <b><tt>TextAlphaBits</tt></b>. If the
|
|
|
2029 |
latter is 1, the same rendering results regardless of the value of
|
|
|
2030 |
<b><tt>AlignToPixels</tt></b>. The initial value defaults to 1, but this
|
|
|
2031 |
may be overridden by the command line argument
|
|
|
2032 |
<b><tt>-dAlignToPixels</tt></b>.
|
|
|
2033 |
</dl>
|
|
|
2034 |
|
|
|
2035 |
|
|
|
2036 |
<dl>
|
|
|
2037 |
<a name="GridFitTT"></a>
|
|
|
2038 |
<dt><b><tt>GridFitTT <integer></tt></b>
|
|
|
2039 |
<dd>Control the use of True Type grid fitting.
|
|
|
2040 |
Ghostscript implements a reduced True Type bytecode interpreter,
|
|
|
2041 |
which can interpret the subset of True Type glyph instructions
|
|
|
2042 |
not covered by Apple's patents. This allows proper rasterization
|
|
|
2043 |
of the Dynalab fonts.
|
|
|
2044 |
<p>
|
|
|
2045 |
The reduced interpreter can't properly grid fit
|
|
|
2046 |
fonts with patented instructions. Therefore Ghostscript implements
|
|
|
2047 |
another grid fitting method for True Type fonts, based on a spot topology analysis.
|
|
|
2048 |
<p>
|
|
|
2049 |
This parameter controls the action of the reduced interpreter and the grid fitter:
|
|
|
2050 |
<ul>
|
|
|
2051 |
<li>
|
|
|
2052 |
A value of 0 disables grid fitting for all True Type fonts. This is a backward compatibility mode.
|
|
|
2053 |
</li>
|
|
|
2054 |
|
|
|
2055 |
<li>
|
|
|
2056 |
A value of 1 enables the grid fitting for glyphs that don't involve
|
|
|
2057 |
patented instructions, using the reduced True Type bytecode interpreter.
|
|
|
2058 |
When a patented instruction is encountered, a warning is printed to stderr,
|
|
|
2059 |
and the glyph is rendered ignoring the entire grid fitting program.
|
|
|
2060 |
</li>
|
|
|
2061 |
|
|
|
2062 |
<li>
|
|
|
2063 |
A value of 2 invokes the topological grid fitter. This value is recommended
|
|
|
2064 |
for common use.
|
|
|
2065 |
</li>
|
|
|
2066 |
|
|
|
2067 |
<li>
|
|
|
2068 |
A value of 3 specifies that the bytecode interpreter to be used
|
|
|
2069 |
to grid fit glyphs that have no patented instructions,
|
|
|
2070 |
and other glyphs are grid fitted topologically. This mode may
|
|
|
2071 |
improve the rendering of some fonts, but in general the best result
|
|
|
2072 |
is not guaranteed.
|
|
|
2073 |
</li>
|
|
|
2074 |
</ul>
|
|
|
2075 |
<p>
|
|
|
2076 |
This parameter defaults to 2, but this
|
|
|
2077 |
may be overridden on the command line with
|
|
|
2078 |
<b><tt>-dGridFitTT=n</tt></b>.
|
|
|
2079 |
<p>
|
|
|
2080 |
The reduced bytecode interpreter is based in part of the work of the
|
|
|
2081 |
<a href="http://freetype.org/">FreeType</a> Team.
|
|
|
2082 |
The topological grid fitting is a new original Ghostscript method.
|
|
|
2083 |
</dl>
|
|
|
2084 |
|
|
|
2085 |
<dl>
|
|
|
2086 |
<dt><b><tt>UseWTS <boolean></tt></b>
|
|
|
2087 |
<dd>If <tt>true</tt>, and if AccurateScreens are specified (either as
|
|
|
2088 |
a user parameter, or as a type 1 halftone dictionary parameter), then
|
|
|
2089 |
the Well Tempered Screening algorithm is used for
|
|
|
2090 |
halftoning. Otherwise, a rational tangent algorithm is chosen, which
|
|
|
2091 |
will typically result in significant differences between the screen
|
|
|
2092 |
angle and ruling requested, and actually rendered. Currently, the
|
|
|
2093 |
performance of WTS is reasonably good when rendering to a full page
|
|
|
2094 |
buffer, but not optimized for banded mode. Thus, when using WTS,
|
|
|
2095 |
disable banding (setting
|
|
|
2096 |
<b><tt>-dMaxBitmap=500000000</tt></b> should work). In a future
|
|
|
2097 |
version, WTS will be optimized for banded mode, and
|
|
|
2098 |
<b><tt>UseWTS</tt></b> will be <tt>true</tt> by default.
|
|
|
2099 |
|
|
|
2100 |
<p>
|
|
|
2101 |
<b>Note:</b> Currently, <b><tt>UseWTS</tt></b> can only be set using
|
|
|
2102 |
the PostScript user parameters mechanism, not on the command line with
|
|
|
2103 |
a <b><tt>-d</tt></b> switch. Use this code to enable it:
|
|
|
2104 |
|
|
|
2105 |
<blockquote><pre>
|
|
|
2106 |
<< /UseWTS true >> setuserparams
|
|
|
2107 |
</pre></blockquote>
|
|
|
2108 |
</dl>
|
|
|
2109 |
|
|
|
2110 |
<hr>
|
|
|
2111 |
|
|
|
2112 |
<h2><a name="Miscellaneous_additions"></a>Miscellaneous additions</h2>
|
|
|
2113 |
|
|
|
2114 |
<h3><a name="Extended_semantics_of_run"></a>Extended semantics of 'run'</h3>
|
|
|
2115 |
|
|
|
2116 |
<p>
|
|
|
2117 |
The operator <b><tt>run</tt></b> can take either a string or a file as its argument. In
|
|
|
2118 |
the latter case, it just runs the file, closing it at the end, and trapping
|
|
|
2119 |
errors just as for the string case.
|
|
|
2120 |
|
|
|
2121 |
<h3><a name="DecodingResources"></a>Decoding resources</h3>
|
|
|
2122 |
|
|
|
2123 |
<p>
|
|
|
2124 |
<b><tt>Decoding</tt></b> is a Ghostscript-specific resource category. It contains
|
|
|
2125 |
various resources for emulating PostScript fonts with other font technologies.
|
|
|
2126 |
Instances of the <tt>Decoding</tt> category are tables which map PostScript glyph
|
|
|
2127 |
names to character codes used with TrueType, Intellifont, Microtype and other font formats.
|
|
|
2128 |
|
|
|
2129 |
<p>
|
|
|
2130 |
Currently Ghostscript is capable of PostScript font emulation in 2 ways :
|
|
|
2131 |
<li>
|
|
|
2132 |
1. Through <a href="./Use.htm#FAPI_run">FAPI</a> plugins, and
|
|
|
2133 |
</li>
|
|
|
2134 |
<li>
|
|
|
2135 |
2. With TrueType font files, using the native font renderer, by
|
|
|
2136 |
specifying TrueType font names or files in <a href="../lib/Fontmap">lib/Fontmap</a>.
|
|
|
2137 |
</li>
|
|
|
2138 |
<p>
|
|
|
2139 |
<b><tt>Decoding</tt></b> resources are not current used by the native font renderer.
|
|
|
2140 |
|
|
|
2141 |
<p>
|
|
|
2142 |
An instance of the <b><tt>Decoding</tt></b> resource category is
|
|
|
2143 |
a dictionary. The dictionary keys are PostScript glyph names and the
|
|
|
2144 |
values are character codes. The name of the resource instance should
|
|
|
2145 |
reflect the character set for which it maps. For example,
|
|
|
2146 |
<b><tt>/Unicode</tt></b> <b><tt>/Decoding</tt></b> resource maps to
|
|
|
2147 |
Unicode UTF-16.
|
|
|
2148 |
|
|
|
2149 |
<p>
|
|
|
2150 |
The rules for using <b><tt>Decoding</tt></b> resources in particular
|
|
|
2151 |
cases are specified in the configuration file
|
|
|
2152 |
<a href="../lib/xlatmap">lib/xlatmap</a>. See the file itself for more
|
|
|
2153 |
information.
|
|
|
2154 |
|
|
|
2155 |
<p>
|
|
|
2156 |
The file format for <b><tt>Decoding</tt></b> resource files is
|
|
|
2157 |
generic PostScript.
|
|
|
2158 |
Users may want to define custom <b><tt>Decoding</tt></b> resources.
|
|
|
2159 |
The <b><tt>ParseDecoding</tt></b> procset defined in
|
|
|
2160 |
<a href="../lib/gs_ciddc.ps">lib/gs_ciddc.ps</a> allows representation
|
|
|
2161 |
of the table in a comfortable form.
|
|
|
2162 |
|
|
|
2163 |
|
|
|
2164 |
<h3><a name="CIDDecodingResources"></a>CIDDecoding resources</h3>
|
|
|
2165 |
|
|
|
2166 |
<p>
|
|
|
2167 |
<b><tt>CIDDecoding</tt></b> resources are similar to <b><tt>Decoding</tt></b>
|
|
|
2168 |
resources, except they map Charaacter Identifiers (CIDs) rather than glyph names.
|
|
|
2169 |
Another difference is that the native Ghostscript font renderer already uses
|
|
|
2170 |
<b><tt>CIDDecoding</tt></b> resources while emulate CID fonts with TrueType.
|
|
|
2171 |
|
|
|
2172 |
<p>
|
|
|
2173 |
An instance of the <b><tt>CIDDecoding</tt></b> resource category is
|
|
|
2174 |
a dictionary of strings. Keys in the dictionary are integers,
|
|
|
2175 |
which correspond to high order byte of a CID. Values are
|
|
|
2176 |
512-bytes strings. Each string represents 256 character codes,
|
|
|
2177 |
corresponding various values of the lower byte of CID.
|
|
|
2178 |
Each character code ocupies 2 bytes, high order byte first.
|
|
|
2179 |
Two zero bytes represent mapping to the default character.
|
|
|
2180 |
|
|
|
2181 |
<p>
|
|
|
2182 |
The Ghostscript library is capable of generating some <b><tt>CIDDecoding</tt></b>
|
|
|
2183 |
instances automatically, using the appropriate <b><tt>CMap</tt></b> (character map)
|
|
|
2184 |
resources. This covers most of practical cases if the neccessary <b><tt>CMap</tt></b>
|
|
|
2185 |
resources are provided. See the table <b><tt>.CMapChooser</tt></b> in
|
|
|
2186 |
<a href="../lib/gs_ciddc.ps">lib/gs_ciddc.ps</a>
|
|
|
2187 |
for the names of automatically gerenated resources and associated <b><tt>CMap</tt></b>s.
|
|
|
2188 |
They allow to mapping CNS1, GB1, Japan1, Japan2 and Korea1 CID sets to TrueType
|
|
|
2189 |
character sets known as Unicode (exactly UTF-16), Big5,
|
|
|
2190 |
GB1213, ShiftJIS, Johab and Wansung.
|
|
|
2191 |
|
|
|
2192 |
<p>
|
|
|
2193 |
The file format for <b><tt>CIDDecoding</tt></b> resource file is
|
|
|
2194 |
generic PostScript.
|
|
|
2195 |
Users may want to define custom resources to <b><tt>CIDDecoding</tt></b>
|
|
|
2196 |
resource category.
|
|
|
2197 |
|
|
|
2198 |
<h3><a name="GlyphNames2Unicode"></a>GlyphNames2Unicode</h3>
|
|
|
2199 |
<p>
|
|
|
2200 |
<b><tt>GlyphNames2Unicode</tt></b> is an undocumented dictionary which Adobe
|
|
|
2201 |
PostScript printer driver uses to communicate with Adobe Distiller.
|
|
|
2202 |
In this dictionary the keys are glyph names, the values are Unicode UTF-16 codes for them.
|
|
|
2203 |
The dictionaly is stored in the <b><tt>FontInfo</tt></b> dictionary under
|
|
|
2204 |
the key <b><tt>GlyphNames2Unicode</tt></b>. Ghostscript recognises it and uses
|
|
|
2205 |
to generate <b><tt>ToUnicode</tt></b> CMaps with pdfwrite.
|
|
|
2206 |
<p>
|
|
|
2207 |
|
|
|
2208 |
<h3><a name="MultipleResourceDirectories"></a>Multiple Resource directories</h3>
|
|
|
2209 |
|
|
|
2210 |
<p>
|
|
|
2211 |
Since 8.10 release Ghostscript maintains multiple resource directories.
|
|
|
2212 |
|
|
|
2213 |
<p>
|
|
|
2214 |
Ghostscript does not distinguish <b><tt>lib</b></tt> and <b><tt>Resource</b></tt> directories.
|
|
|
2215 |
There is no file name conflicts because
|
|
|
2216 |
<b><tt>lib</b></tt> does not contain subdirectories, but <b><tt>Resource</b></tt>
|
|
|
2217 |
always store files in subdirectories.
|
|
|
2218 |
|
|
|
2219 |
<p>
|
|
|
2220 |
The search method with multiple resource directories
|
|
|
2221 |
appears not fully conforming to PLRM. We cannot unconditionally call
|
|
|
2222 |
<b><tt>ResourceFileName</b></tt> while executing <b><tt>findresource</b></tt>
|
|
|
2223 |
or <b><tt>resourcestatus</b></tt>, <b><tt>resourceforall</b></tt>, because per PLRM it always
|
|
|
2224 |
returns a single path. Therefore Ghostscript implements
|
|
|
2225 |
an extended search method in <b><tt>findresource</b></tt>,
|
|
|
2226 |
<b><tt>resourcestatus</b></tt> and <b><tt>resourceforall</b></tt>, which first calls
|
|
|
2227 |
<b><tt>ResourceFileName</b></tt> and checks whether the returned path
|
|
|
2228 |
points to an existing file. If yes, the file is used,
|
|
|
2229 |
othervise Ghostscript searches all directories specified in
|
|
|
2230 |
<b><tt>LIB_PATH</tt></b>. With a single resource directory
|
|
|
2231 |
it appears conforming to PLRM and equivalent to Adobe implementations.
|
|
|
2232 |
|
|
|
2233 |
<p>
|
|
|
2234 |
<b><tt>ResourceFileName</b></tt> may be used for obtaining a path
|
|
|
2235 |
where a resource file to be installed. In this case
|
|
|
2236 |
Ghostscript to be invoked with <b><tt>-sGenericResourceDir=path</b></tt>,
|
|
|
2237 |
specifying an absolute path. The default value for
|
|
|
2238 |
<b><tt>GenericResourceDir</b></tt> is a relative path. Therefore
|
|
|
2239 |
a default invocation with a PostScript installer
|
|
|
2240 |
will install resource files into <b><tt>/gs/Resource</tt></b>.
|
|
|
2241 |
|
|
|
2242 |
<p>
|
|
|
2243 |
|
|
|
2244 |
<!-- [2.0 end contents] ==================================================== -->
|
|
|
2245 |
|
|
|
2246 |
<!-- [3.0 begin visible trailer] =========================================== -->
|
|
|
2247 |
<hr>
|
|
|
2248 |
|
|
|
2249 |
<p>
|
|
|
2250 |
<small>Copyright © 1996-2005 artofcode LLC. All rights
|
|
|
2251 |
reserved.</small>
|
|
|
2252 |
|
|
|
2253 |
<p>
|
|
|
2254 |
This software is provided AS-IS with no warranty, either express or
|
|
|
2255 |
implied.
|
|
|
2256 |
|
|
|
2257 |
This software is distributed under license and may not be copied,
|
|
|
2258 |
modified or distributed except as expressly authorized under the terms
|
|
|
2259 |
of the license contained in the file LICENSE in this distribution.
|
|
|
2260 |
|
|
|
2261 |
For more information about licensing, please refer to
|
|
|
2262 |
http://www.ghostscript.com/licensing/. For information on
|
|
|
2263 |
commercial licensing, go to http://www.artifex.com/licensing/ or
|
|
|
2264 |
contact Artifex Software, Inc., 101 Lucas Valley Road #110,
|
|
|
2265 |
San Rafael, CA 94903, U.S.A., +1(415)492-9861.
|
|
|
2266 |
|
|
|
2267 |
<p>
|
|
|
2268 |
<small>Ghostscript version 8.53, 20 October 2005
|
|
|
2269 |
|
|
|
2270 |
<!-- [3.0 end visible trailer] ============================================= -->
|
|
|
2271 |
|
|
|
2272 |
</body>
|
|
|
2273 |
</html>
|