WebSVN – planix.SVN – Blame – /os/branches/feature_fixcpp/sys/src/cmd/resample.c

Rev	Author	Line No.	Line
2	-	1	`#include <u.h>`
		2	`#include <libc.h>`
		3	`#include <draw.h>`
		4	`#include <memdraw.h>`
		5
		6	`#define K2 7 /* from -.7 to +.7 inclusive, meaning .2 into each adjacent pixel */`
		7	`#define NK (2*K2+1)`
		8	`double K[NK];`
		9
		10	`double`
		11	`fac(int L)`
		12	`{`
		13	`int i, f;`
		14
		15	`f = 1;`
		16	`for(i=L; i>1; --i)`
		17	`f *= i;`
		18	`return f;`
		19	`}`
		20
		21	`/*`
		22	`* i0(x) is the modified Bessel function, Σ (x/2)^2L / (L!)²`
		23	`* There are faster ways to calculate this, but we precompute`
		24	`* into a table so let's keep it simple.`
		25	`*/`
		26	`double`
		27	`i0(double x)`
		28	`{`
		29	`double v;`
		30	`int L;`
		31
		32	`v = 1.0;`
		33	`for(L=1; L<10; L++)`
		34	`v += pow(x/2., 2*L)/pow(fac(L), 2);`
		35	`return v;`
		36	`}`
		37
		38	`double`
		39	`kaiser(double x, double τ, double α)`
		40	`{`
		41	`if(fabs(x) > τ)`
		42	`return 0.;`
		43	`return i0(αsqrt(1-(xx/(τ*τ))))/i0(α);`
		44	`}`
		45
		46	`void`
		47	`usage(void)`
		48	`{`
		49	`fprint(2, "usage: resample [-x xsize] [-y ysize] [imagefile]\n");`
		50	`fprint(2, "\twhere size is an integer or a percentage in the form 25%%\n");`
		51	`exits("usage");`
		52	`}`
		53
		54	`int`
		55	`getint(char s, int percent)`
		56	`{`
		57	`if(s == nil)`
		58	`usage();`
		59	`*percent = (s[strlen(s)-1] == '%');`
		60	`if(*s == '+')`
		61	`return atoi(s+1);`
		62	`if(*s == '-')`
		63	`return -atoi(s+1);`
		64	`return atoi(s);`
		65	`}`
		66
		67	`void`
		68	`resamplex(uchar in, int off, int d, int inx, uchar out, int outx)`
		69	`{`
		70	`int i, x, k;`
		71	`double X, xx, v, rat;`
		72
		73
		74	`rat = (double)inx/(double)outx;`
		75	`for(x=0; x<outx; x++){`
		76	`if(inx == outx){`
		77	`/* don't resample if size unchanged */`
		78	`out[off+xd] = in[off+xd];`
		79	`continue;`
		80	`}`
		81	`v = 0.0;`
		82	`X = x*rat;`
		83	`for(k=-K2; k<=K2; k++){`
		84	`xx = X + rat*k/10.;`
		85	`i = xx;`
		86	`if(i < 0)`
		87	`i = 0;`
		88	`if(i >= inx)`
		89	`i = inx-1;`
		90	`v += in[off+id] K[K2+k];`
		91	`}`
		92	`out[off+x*d] = v;`
		93	`}`
		94	`}`
		95
		96	`void`
		97	`resampley(uchar in, int off, int iny, uchar out, int outy)`
		98	`{`
		99	`int y, i, k;`
		100	`double Y, yy, v, rat;`
		101
		102	`rat = (double)iny/(double)outy;`
		103	`for(y=0; y<outy; y++){`
		104	`if(iny == outy){`
		105	`/* don't resample if size unchanged */`
		106	`out[y][off] = in[y][off];`
		107	`continue;`
		108	`}`
		109	`v = 0.0;`
		110	`Y = y*rat;`
		111	`for(k=-K2; k<=K2; k++){`
		112	`yy = Y + rat*k/10.;`
		113	`i = yy;`
		114	`if(i < 0)`
		115	`i = 0;`
		116	`if(i >= iny)`
		117	`i = iny-1;`
		118	`v += in[i][off] * K[K2+k];`
		119	`}`
		120	`out[y][off] = v;`
		121	`}`
		122
		123	`}`
		124
		125	`int`
		126	`max(int a, int b)`
		127	`{`
		128	`if(a > b)`
		129	`return a;`
		130	`return b;`
		131	`}`
		132
		133	`Memimage*`
		134	`resample(int xsize, int ysize, Memimage *m)`
		135	`{`
		136	`int i, j, bpl, nchan;`
		137	`Memimage *new;`
		138	`uchar oscan, nscan;`
		139
		140	`new = allocmemimage(Rect(0, 0, xsize, ysize), m->chan);`
		141	`if(new == nil)`
		142	`sysfatal("can't allocate new image: %r");`
		143
		144	`oscan = malloc(Dy(m->r)sizeof(uchar));`
		145	`nscan = malloc(max(ysize, Dy(m->r))sizeof(uchar));`
		146	`if(oscan == nil \|\| nscan == nil)`
		147	`sysfatal("can't allocate: %r");`
		148
		149	`/* unload original image into scan lines */`
		150	`bpl = bytesperline(m->r, m->depth);`
		151	`for(i=0; i<Dy(m->r); i++){`
		152	`oscan[i] = malloc(bpl);`
		153	`if(oscan[i] == nil)`
		154	`sysfatal("can't allocate: %r");`
		155	`j = unloadmemimage(m, Rect(m->r.min.x, m->r.min.y+i, m->r.max.x, m->r.min.y+i+1), oscan[i], bpl);`
		156	`if(j != bpl)`
		157	`sysfatal("unloadmemimage");`
		158	`}`
		159
		160	`/* allocate scan lines for destination. we do y first, so need at least Dy(m->r) lines */`
		161	`bpl = bytesperline(Rect(0, 0, xsize, Dy(m->r)), m->depth);`
		162	`for(i=0; i<max(ysize, Dy(m->r)); i++){`
		163	`nscan[i] = malloc(bpl);`
		164	`if(nscan[i] == nil)`
		165	`sysfatal("can't allocate: %r");`
		166	`}`
		167
		168	`/* resample in X */`
		169	`nchan = m->depth/8;`
		170	`for(i=0; i<Dy(m->r); i++){`
		171	`for(j=0; j<nchan; j++){`
		172	`if(j==0 && m->chan==XRGB32)`
		173	`continue;`
		174	`resamplex(oscan[i], j, nchan, Dx(m->r), nscan[i], xsize);`
		175	`}`
		176	`free(oscan[i]);`
		177	`oscan[i] = nscan[i];`
		178	`nscan[i] = malloc(bpl);`
		179	`if(nscan[i] == nil)`
		180	`sysfatal("can't allocate: %r");`
		181	`}`
		182
		183	`/* resample in Y */`
		184	`for(i=0; i<xsize; i++)`
		185	`for(j=0; j<nchan; j++)`
		186	`resampley(oscan, nchan*i+j, Dy(m->r), nscan, ysize);`
		187
		188	`/* pack data into destination */`
		189	`bpl = bytesperline(new->r, m->depth);`
		190	`for(i=0; i<ysize; i++){`
		191	`j = loadmemimage(new, Rect(0, i, xsize, i+1), nscan[i], bpl);`
		192	`if(j != bpl)`
		193	`sysfatal("loadmemimage: %r");`
		194	`}`
		195	`return new;`
		196	`}`
		197
		198	`void`
		199	`main(int argc, char *argv[])`
		200	`{`
		201	`int i, fd, xsize, ysize, xpercent, ypercent;`
		202	`Rectangle rparam;`
		203	`Memimage m, new, t1, t2;`
		204	`char *file;`
		205	`ulong tchan;`
		206	`char tmp[100];`
		207	`double v;`
		208
		209	`for(i=-K2; i<=K2; i++){`
		210	`K[K2+i] = kaiser(i/10., K2/10., 4.);`
		211	`// print("%g %g\n", i/10., K[K2+i]);`
		212	`}`
		213
		214	`/* normalize */`
		215	`v = 0.0;`
		216	`for(i=0; i<NK; i++)`
		217	`v += K[i];`
		218	`for(i=0; i<NK; i++)`
		219	`K[i] /= v;`
		220
		221	`memimageinit();`
		222	`memset(&rparam, 0, sizeof rparam);`
		223	`xsize = ysize = 0;`
		224	`xpercent = ypercent = 0;`
		225
		226	`ARGBEGIN{`
		227	`case 'a': /* compatibility; equivalent to just -x or -y */`
		228	`if(xsize != 0 \|\| ysize != 0)`
		229	`usage();`
		230	`xsize = getint(ARGF(), &xpercent);`
		231	`if(xsize <= 0)`
		232	`usage();`
		233	`ysize = xsize;`
		234	`ypercent = xpercent;`
		235	`break;`
		236	`case 'x':`
		237	`if(xsize != 0)`
		238	`usage();`
		239	`xsize = getint(ARGF(), &xpercent);`
		240	`if(xsize <= 0)`
		241	`usage();`
		242	`break;`
		243	`case 'y':`
		244	`if(ysize != 0)`
		245	`usage();`
		246	`ysize = getint(ARGF(), &ypercent);`
		247	`if(ysize <= 0)`
		248	`usage();`
		249	`break;`
		250	`default:`
		251	`usage();`
		252	`}ARGEND`
		253
		254	`if(xsize == 0 && ysize == 0)`
		255	`usage();`
		256
		257	`file = "<stdin>";`
		258	`fd = 0;`
		259	`if(argc > 1)`
		260	`usage();`
		261	`else if(argc == 1){`
		262	`file = argv[0];`
		263	`fd = open(file, OREAD);`
		264	`if(fd < 0)`
		265	`sysfatal("can't open %s: %r", file);`
		266	`}`
		267
		268	`m = readmemimage(fd);`
		269	`if(m == nil)`
		270	`sysfatal("can't read %s: %r", file);`
		271
		272	`if(xpercent)`
		273	`xsize = Dx(m->r)*xsize/100;`
		274	`if(ypercent)`
		275	`ysize = Dy(m->r)*ysize/100;`
		276	`if(ysize == 0)`
		277	`ysize = (xsize * Dy(m->r)) / Dx(m->r);`
		278	`if(xsize == 0)`
		279	`xsize = (ysize * Dx(m->r)) / Dy(m->r);`
		280
		281	`new = nil;`
		282	`switch(m->chan){`
		283
		284	`case GREY8:`
		285	`case RGB24:`
		286	`case RGBA32:`
		287	`case ARGB32:`
		288	`case XRGB32:`
		289	`new = resample(xsize, ysize, m);`
		290	`break;`
		291
		292	`case CMAP8:`
		293	`case RGB15:`
		294	`case RGB16:`
		295	`tchan = RGB24;`
		296	`goto Convert;`
		297
		298	`case GREY1:`
		299	`case GREY2:`
		300	`case GREY4:`
		301	`tchan = GREY8;`
		302	`Convert:`
		303	`/* use library to convert to byte-per-chan form, then convert back */`
		304	`t1 = allocmemimage(m->r, tchan);`
		305	`if(t1 == nil)`
		306	`sysfatal("can't allocate temporary image: %r");`
		307	`memimagedraw(t1, t1->r, m, m->r.min, nil, ZP, S);`
		308	`t2 = resample(xsize, ysize, t1);`
		309	`freememimage(t1);`
		310	`new = allocmemimage(Rect(0, 0, xsize, ysize), m->chan);`
		311	`if(new == nil)`
		312	`sysfatal("can't allocate new image: %r");`
		313	`/* should do error diffusion here */`
		314	`memimagedraw(new, new->r, t2, t2->r.min, nil, ZP, S);`
		315	`freememimage(t2);`
		316	`break;`
		317
		318	`default:`
		319	`sysfatal("can't handle channel type %s", chantostr(tmp, m->chan));`
		320	`}`
		321
		322	`assert(new);`
		323	`if(writememimage(1, new) < 0)`
		324	`sysfatal("write error on output: %r");`
		325
		326	`exits(nil);`
		327	`}`

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