Subversion Repositories planix.SVN

Rev

Go to most recent revision | Details | Last modification | View Log | RSS feed

Rev Author Line No. Line
2 - 1 
.TH ADDPT 2
2 
.SH NAME
3 
addpt, subpt, mulpt, divpt, rectaddpt, rectsubpt, insetrect, canonrect, eqpt, eqrect, ptinrect, rectinrect, rectXrect, rectclip, combinerect, Dx, Dy, Pt, Rect, Rpt \- arithmetic on points and rectangles
4 
.SH SYNOPSIS
5 
.B #include <u.h>
6 
.br
7 
.B #include <libc.h>
8 
.br
9 
.B #include <draw.h>
10 
.PP
11 
.B
12 
Point	addpt(Point p, Point q)
13 
.PP
14 
.B
15 
Point	subpt(Point p, Point q)
16 
.PP
17 
.B
18 
Point	mulpt(Point p, int a)
19 
.PP
20 
.B
21 
Point	divpt(Point p, int a)
22 
.PP
23 
.B
24 
Rectangle	rectaddpt(Rectangle r, Point p)
25 
.PP
26 
.B
27 
Rectangle	rectsubpt(Rectangle r, Point p)
28 
.PP
29 
.B
30 
Rectangle	insetrect(Rectangle r, int n)
31 
.PP
32 
.B
33 
Rectangle	canonrect(Rectangle r)
34 
.PP
35 
.B
36 
int		eqpt(Point p, Point q)
37 
.PP
38 
.B
39 
int		eqrect(Rectangle r, Rectangle s)
40 
.PP
41 
.B
42 
int		ptinrect(Point p, Rectangle r)
43 
.PP
44 
.B
45 
int		rectinrect(Rectangle r, Rectangle s)
46 
.PP
47 
.B
48 
int		rectXrect(Rectangle r, Rectangle s)
49 
.PP
50 
.B
51 
int		rectclip(Rectangle *rp, Rectangle b)
52 
.PP
53 
.B
54 
void		combinerect(Rectangle *rp, Rectangle b)
55 
.PP
56 
.B
57 
int		Dx(Rectangle r)
58 
.PP
59 
.B
60 
int		Dy(Rectangle r)
61 
.PP
62 
.B
63 
Point	Pt(int x, int y)
64 
.PP
65 
.B
66 
Rectangle	Rect(int x0, int y0, int x1, int y1)
67 
.PP
68 
.B
69 
Rectangle	Rpt(Point p, Point q)
70 
.SH DESCRIPTION
71 
The functions
72 
.IR Pt ,
73 
.I Rect
74 
and
75 
.I Rpt
76 
construct geometrical data types from their components.
77 
.PP
78 
.I Addpt
79 
returns the Point
80 
sum of its arguments:
81 
.BI Pt( p .x+ q .x,
82 
.IB p .y+ q .y) \f1.
83 
.I Subpt
84 
returns the Point
85 
difference of its arguments:
86 
.BI Pt( p .x- q .x,
87 
.IB p .y- q .y) \f1.
88 
.I Mulpt
89 
returns the Point
90 
.BI Pt( p .x* a ,
91 
.IB p .y* a ) \f1.
92 
.I Divpt
93 
returns the Point
94 
.BI Pt( p .x/ a ,
95 
.IB p .y/ a ) \f1.
96 
.PP
97 
.I Rectaddpt
98 
returns the Rectangle
99 
.BI Rect(add( r .min,
100 
.IB p ) \f1,
101 
.BI add( r .max,
102 
.IB p )) \f1;
103 
.I rectsubpt
104 
returns the Rectangle
105 
.BI Rpt(sub( r .min,
106 
.IB p ),
107 
.BI sub( r .max,
108 
.IB p ))\fR.
109 
.PP
110 
.I Insetrect
111 
returns the Rectangle
112 
.BI Rect( r .min.x+ n \f1,
113 
.IB r .min.y+ n \f1,
114 
.IB r .max.x- n \f1,
115 
.IB r .max.y- n ) \f1.
116 
.PP
117 
.I Canonrect
118 
returns a rectangle with the same extent as
119 
.IR r ,
120 
canonicalized so that
121 
.B min.x
122 
≤
123 
.BR max.x ,
124 
and
125 
.B min.y
126 
≤
127 
.BR max.y .
128 
.PP
129 
.I Eqpt
130 
compares its argument Points and returns
131 
 
132 
1 if equal.
133 
.I Eqrect
134 
does the same for its argument Rectangles.
135 
.PP
136 
.I Ptinrect
137 
returns 1 if
138 
.I p
139 
is a point within
140 
.IR r ,
141 
and 0 otherwise.
142 
.PP
143 
.I Rectinrect
144 
returns 1 if all the pixels in
145 
.I r
146 
are also in
147 
.IR s ,
148 
and 0 otherwise.
149 
.PP
150 
.I RectXrect
151 
returns 1 if
152 
.I r
153 
and
154 
.I s
155 
share any point, and 0 otherwise.
156 
.PP
157 
.I Rectclip
158 
clips in place
159 
the Rectangle pointed to by
160 
.I rp
161 
so that it is completely contained within
162 
.IR b .
163 
The return value is 1 if any part of
164 
.RI * rp
165 
is within
166 
.IR b .
167 
Otherwise, the return value is 0 and
168 
.RI * rp
169 
is unchanged.
170 
.PP
171 
.I Combinerect
172 
overwrites
173 
.B *rp
174 
with the smallest rectangle sufficient to cover all the pixels of
175 
.B *rp
176 
and
177 
.BR b .
178 
.PP
179 
The functions
180 
.I Dx
181 
and
182 
.I Dy
183 
give the width (Δx) and height (Δy) of a Rectangle.
184 
They are implemented as macros.
185 
.SH SOURCE
186 
.B /sys/src/libdraw
187 
.SH SEE ALSO
188 
.IR graphics (2)