fix documentation of i_gpix_d (internal)
[imager.git] / rotate.im
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1/*
2=head1 NAME
3
999f4294 4 rotate.im - implements image rotations
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5
6=head1 SYNOPSIS
7
8 i_img *i_rotate90(i_img *src, int degrees)
9
10=head1 DESCRIPTION
11
12Implements basic 90 degree rotations of an image.
13
14Other rotations will be added as tuits become available.
15
16=cut
17*/
18
92bda632 19#include "imager.h"
13c9a303 20#include "imageri.h"
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21#include <math.h> /* for floor() */
22
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23#define ROT_DEBUG(x)
24
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25i_img *i_rotate90(i_img *src, int degrees) {
26 i_img *targ;
8d14daab 27 i_img_dim x, y;
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28
29 i_clear_error();
30
31 if (degrees == 180) {
32 /* essentially the same as flipxy(..., 2) except that it's not
33 done in place */
34 targ = i_sametype(src, src->xsize, src->ysize);
35 if (src->type == i_direct_type) {
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36#code src->bits <= 8
37 IM_COLOR *vals = mymalloc(src->xsize * sizeof(IM_COLOR));
38 for (y = 0; y < src->ysize; ++y) {
39 IM_COLOR tmp;
40 IM_GLIN(src, 0, src->xsize, y, vals);
41 for (x = 0; x < src->xsize/2; ++x) {
42 tmp = vals[x];
43 vals[x] = vals[src->xsize - x - 1];
44 vals[src->xsize - x - 1] = tmp;
45 }
46 IM_PLIN(targ, 0, src->xsize, src->ysize - y - 1, vals);
faa9b3e7 47 }
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48 myfree(vals);
49#/code
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50 }
51 else {
52 i_palidx *vals = mymalloc(src->xsize * sizeof(i_palidx));
53
54 for (y = 0; y < src->ysize; ++y) {
55 i_palidx tmp;
56 i_gpal(src, 0, src->xsize, y, vals);
57 for (x = 0; x < src->xsize/2; ++x) {
58 tmp = vals[x];
59 vals[x] = vals[src->xsize - x - 1];
60 vals[src->xsize - x - 1] = tmp;
61 }
62 i_ppal(targ, 0, src->xsize, src->ysize - y - 1, vals);
63 }
64
65 myfree(vals);
66 }
67
68 return targ;
69 }
70 else if (degrees == 270 || degrees == 90) {
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71 i_img_dim tx, txstart, txinc;
72 i_img_dim ty, tystart, tyinc;
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73
74 if (degrees == 270) {
75 txstart = 0;
76 txinc = 1;
77 tystart = src->xsize-1;
78 tyinc = -1;
79 }
80 else {
81 txstart = src->ysize-1;
82 txinc = -1;
83 tystart = 0;
84 tyinc = 1;
85 }
86 targ = i_sametype(src, src->ysize, src->xsize);
87 if (src->type == i_direct_type) {
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88#code src->bits <= 8
89 IM_COLOR *vals = mymalloc(src->xsize * sizeof(IM_COLOR));
90
91 tx = txstart;
92 for (y = 0; y < src->ysize; ++y) {
93 IM_GLIN(src, 0, src->xsize, y, vals);
94 ty = tystart;
95 for (x = 0; x < src->xsize; ++x) {
96 IM_PPIX(targ, tx, ty, vals+x);
97 ty += tyinc;
98 }
99 tx += txinc;
faa9b3e7 100 }
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101 myfree(vals);
102#/code
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103 }
104 else {
105 i_palidx *vals = mymalloc(src->xsize * sizeof(i_palidx));
106
107 tx = txstart;
108 for (y = 0; y < src->ysize; ++y) {
109 i_gpal(src, 0, src->xsize, y, vals);
110 ty = tystart;
111 for (x = 0; x < src->xsize; ++x) {
112 i_ppal(targ, tx, tx+1, ty, vals+x);
113 ty += tyinc;
114 }
115 tx += txinc;
116 }
117 myfree(vals);
118 }
119 return targ;
120 }
121 else {
122 i_push_error(0, "i_rotate90() only rotates at 90, 180, or 270 degrees");
123 return NULL;
124 }
125}
126
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127/* linear interpolation */
128static i_color interp_i_color(i_color before, i_color after, double pos,
129 int channels) {
130 i_color out;
131 int ch;
132
133 pos -= floor(pos);
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134 if (channels == 1 || channels == 3) {
135 for (ch = 0; ch < channels; ++ch)
289d65f4 136 out.channel[ch] = ((1-pos) * before.channel[ch] + pos * after.channel[ch]) + 0.5;
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137 }
138 else {
139 int total_cover = (1-pos) * before.channel[channels-1]
140 + pos * after.channel[channels-1];
141
142 total_cover = I_LIMIT_8(total_cover);
143 if (total_cover) {
144 double before_alpha = before.channel[channels-1] / 255.0;
145 double after_alpha = after.channel[channels-1] / 255.0;
146 double total_alpha = before_alpha * (1-pos) + after_alpha * pos;
147
148 for (ch = 0; ch < channels-1; ++ch) {
149 int out_level = ((1-pos) * before.channel[ch] * before_alpha +
ef74691a 150 pos * after.channel[ch] * after_alpha) / total_alpha + 0.5;
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151
152 out.channel[ch] = I_LIMIT_8(out_level);
153 }
154 }
155
156 out.channel[channels-1] = total_cover;
157 }
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158
159 return out;
160}
161
162/* hopefully this will be inlined (it is with -O3 with gcc 2.95.4) */
163/* linear interpolation */
164static i_fcolor interp_i_fcolor(i_fcolor before, i_fcolor after, double pos,
165 int channels) {
166 i_fcolor out;
167 int ch;
168
169 pos -= floor(pos);
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170 if (channels == 1 || channels == 3) {
171 for (ch = 0; ch < channels; ++ch)
172 out.channel[ch] = (1-pos) * before.channel[ch] + pos * after.channel[ch];
173 }
174 else {
175 double total_cover = (1-pos) * before.channel[channels-1]
176 + pos * after.channel[channels-1];
177
178 total_cover = I_LIMIT_DOUBLE(total_cover);
179 if (total_cover) {
180 double before_alpha = before.channel[channels-1];
181 double after_alpha = after.channel[channels-1];
182 double total_alpha = before_alpha * (1-pos) + after_alpha * pos;
183
184 for (ch = 0; ch < channels-1; ++ch) {
185 double out_level = ((1-pos) * before.channel[ch] * before_alpha +
186 pos * after.channel[ch] * after_alpha) / total_alpha;
187
188 out.channel[ch] = I_LIMIT_DOUBLE(out_level);
189 }
190 }
191
192 out.channel[channels-1] = total_cover;
193 }
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194
195 return out;
196}
197
8d14daab 198i_img *i_matrix_transform_bg(i_img *src, i_img_dim xsize, i_img_dim ysize, const double *matrix,
97ac0a96 199 const i_color *backp, const i_fcolor *fbackp) {
faa9b3e7 200 i_img *result = i_sametype(src, xsize, ysize);
8d14daab 201 i_img_dim x, y;
faa9b3e7 202 int ch;
8d14daab 203 i_img_dim i, j;
faa9b3e7 204 double sx, sy, sz;
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205
206 if (src->type == i_direct_type) {
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207#code src->bits <= 8
208 IM_COLOR *vals = mymalloc(xsize * sizeof(IM_COLOR));
209 IM_COLOR back;
faa9b3e7 210
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211#ifdef IM_EIGHT_BIT
212 if (backp) {
213 back = *backp;
214 }
215 else if (fbackp) {
216 for (ch = 0; ch < src->channels; ++ch) {
0a53238e 217 i_fsample_t fsamp;
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218 fsamp = fbackp->channel[ch];
219 back.channel[ch] = fsamp < 0 ? 0 : fsamp > 1 ? 255 : fsamp * 255;
faa9b3e7 220 }
faa9b3e7 221 }
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222#else
223#define interp_i_color interp_i_fcolor
224 if (fbackp) {
225 back = *fbackp;
226 }
227 else if (backp) {
228 for (ch = 0; ch < src->channels; ++ch)
229 back.channel[ch] = backp->channel[ch] / 255.0;
230 }
231#endif
faa9b3e7 232 else {
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233 for (ch = 0; ch < src->channels; ++ch)
234 back.channel[ch] = 0;
235 }
faa9b3e7 236
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237 for (y = 0; y < ysize; ++y) {
238 for (x = 0; x < xsize; ++x) {
239 /* dividing by sz gives us the ability to do perspective
240 transforms */
241 sz = x * matrix[6] + y * matrix[7] + matrix[8];
242 if (fabs(sz) > 0.0000001) {
243 sx = (x * matrix[0] + y * matrix[1] + matrix[2]) / sz;
244 sy = (x * matrix[3] + y * matrix[4] + matrix[5]) / sz;
245 }
246 else {
247 sx = sy = 0;
248 }
249
250 /* anything outside these ranges is either a broken co-ordinate
251 or outside the source */
252 if (fabs(sz) > 0.0000001
253 && sx >= -1 && sx < src->xsize
254 && sy >= -1 && sy < src->ysize) {
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255 i_img_dim bx = floor(sx);
256 i_img_dim by = floor(sy);
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257
258 ROT_DEBUG(fprintf(stderr, "map " i_DFp " to %g,%g\n", i_DFcp(x, y), sx, sy));
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259 if (sx != bx) {
260 if (sy != by) {
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261 IM_COLOR c[2][2];
262 IM_COLOR ci2[2];
289d65f4 263 ROT_DEBUG(fprintf(stderr, " both non-int\n"));
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264 for (i = 0; i < 2; ++i)
265 for (j = 0; j < 2; ++j)
1e9de315 266 if (IM_GPIX(src, bx+i, by+j, &c[j][i]))
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267 c[j][i] = back;
268 for (j = 0; j < 2; ++j)
269 ci2[j] = interp_i_color(c[j][0], c[j][1], sx, src->channels);
270 vals[x] = interp_i_color(ci2[0], ci2[1], sy, src->channels);
271 }
272 else {
273 IM_COLOR ci2[2];
289d65f4 274 ROT_DEBUG(fprintf(stderr, " y int, x non-int\n"));
999f4294 275 for (i = 0; i < 2; ++i)
1e9de315 276 if (IM_GPIX(src, bx+i, sy, ci2+i))
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277 ci2[i] = back;
278 vals[x] = interp_i_color(ci2[0], ci2[1], sx, src->channels);
279 }
280 }
281 else {
282 if (sy != (i_img_dim)sy) {
283 IM_COLOR ci2[2];
289d65f4 284 ROT_DEBUG(fprintf(stderr, " x int, y non-int\n"));
999f4294 285 for (i = 0; i < 2; ++i)
1e9de315 286 if (IM_GPIX(src, bx, by+i, ci2+i))
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287 ci2[i] = back;
288 vals[x] = interp_i_color(ci2[0], ci2[1], sy, src->channels);
289 }
290 else {
289d65f4 291 ROT_DEBUG(fprintf(stderr, " both int\n"));
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292 /* all the world's an integer */
293 if (IM_GPIX(src, sx, sy, vals+x))
294 vals[x] = back;
295 }
296 }
297 }
298 else {
299 vals[x] = back;
300 }
faa9b3e7 301 }
999f4294 302 IM_PLIN(result, 0, xsize, y, vals);
faa9b3e7 303 }
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304 myfree(vals);
305#undef interp_i_color
306#/code
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307 }
308 else {
309 /* don't interpolate for a palette based image */
310 i_palidx *vals = mymalloc(xsize * sizeof(i_palidx));
0d3b936e 311 i_palidx back = 0;
0d3b936e 312 int minval = 256 * 4;
8d14daab 313 i_img_dim ix, iy;
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314 i_color want_back;
315 i_fsample_t fsamp;
faa9b3e7 316
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317 if (backp) {
318 want_back = *backp;
319 }
320 else if (fbackp) {
321 for (ch = 0; ch < src->channels; ++ch) {
322 fsamp = fbackp->channel[ch];
323 want_back.channel[ch] = fsamp < 0 ? 0 : fsamp > 1 ? 255 : fsamp * 255;
324 }
325 }
326 else {
327 for (ch = 0; ch < src->channels; ++ch)
328 want_back.channel[ch] = 0;
329 }
330
331 /* find the closest color */
332 for (i = 0; i < i_colorcount(src); ++i) {
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333 i_color temp;
334 int tempval;
335 i_getcolors(src, i, &temp, 1);
336 tempval = 0;
337 for (ch = 0; ch < src->channels; ++ch) {
0d3b936e 338 tempval += abs(want_back.channel[ch] - temp.channel[ch]);
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339 }
340 if (tempval < minval) {
0d3b936e 341 back = i;
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342 minval = tempval;
343 }
344 }
345
346 for (y = 0; y < ysize; ++y) {
347 for (x = 0; x < xsize; ++x) {
348 /* dividing by sz gives us the ability to do perspective
349 transforms */
350 sz = x * matrix[6] + y * matrix[7] + matrix[8];
351 if (abs(sz) > 0.0000001) {
352 sx = (x * matrix[0] + y * matrix[1] + matrix[2]) / sz;
353 sy = (x * matrix[3] + y * matrix[4] + matrix[5]) / sz;
354 }
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355 else {
356 sx = sy = 0;
357 }
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358
359 /* anything outside these ranges is either a broken co-ordinate
360 or outside the source */
361 if (abs(sz) > 0.0000001
362 && sx >= -0.5 && sx < src->xsize-0.5
363 && sy >= -0.5 && sy < src->ysize-0.5) {
364
365 /* all the world's an integer */
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366 ix = (i_img_dim)(sx+0.5);
367 iy = (i_img_dim)(sy+0.5);
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368 if (!i_gpal(src, ix, ix+1, iy, vals+x))
369 vals[i] = back;
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370 }
371 else {
0d3b936e 372 vals[x] = back;
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373 }
374 }
375 i_ppal(result, 0, xsize, y, vals);
376 }
377 myfree(vals);
378 }
379
380 return result;
381}
382
8d14daab 383i_img *i_matrix_transform(i_img *src, i_img_dim xsize, i_img_dim ysize, const double *matrix) {
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384 return i_matrix_transform_bg(src, xsize, ysize, matrix, NULL, NULL);
385}
386
35891892 387static void
97ac0a96 388i_matrix_mult(double *dest, const double *left, const double *right) {
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389 int i, j, k;
390 double accum;
391
392 for (i = 0; i < 3; ++i) {
393 for (j = 0; j < 3; ++j) {
394 accum = 0.0;
395 for (k = 0; k < 3; ++k) {
396 accum += left[3*i+k] * right[3*k+j];
397 }
398 dest[3*i+j] = accum;
399 }
400 }
401}
402
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403#define numfmt "%23g"
404
1e9de315 405ROT_DEBUG(static void dump_mat(const char *name, double *f) {
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406 fprintf(stderr, "%s:\n " numfmt " " numfmt " " numfmt "\n"
407 " " numfmt " " numfmt " " numfmt "\n"
408 " " numfmt " " numfmt " " numfmt "\n",
409 name, f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8]);
410 })
411
0d3b936e 412i_img *i_rotate_exact_bg(i_img *src, double amount,
97ac0a96 413 const i_color *backp, const i_fcolor *fbackp) {
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414 double xlate1[9] = { 0 };
415 double rotate[9];
416 double xlate2[9] = { 0 };
417 double temp[9], matrix[9];
8d14daab 418 i_img_dim x1, x2, y1, y2, newxsize, newysize;
faa9b3e7 419
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420 ROT_DEBUG(fprintf(stderr, "rotate angle %.20g\n", amount));
421
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422 /* first translate the centre of the image to (0,0) */
423 xlate1[0] = 1;
289d65f4 424 xlate1[2] = (src->xsize-1)/2.0;
faa9b3e7 425 xlate1[4] = 1;
289d65f4 426 xlate1[5] = (src->ysize-1)/2.0;
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427 xlate1[8] = 1;
428
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429 ROT_DEBUG(dump_mat("xlate1", xlate1));
430
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431 /* rotate around (0.0) */
432 rotate[0] = cos(amount);
433 rotate[1] = sin(amount);
434 rotate[2] = 0;
435 rotate[3] = -rotate[1];
436 rotate[4] = rotate[0];
437 rotate[5] = 0;
438 rotate[6] = 0;
439 rotate[7] = 0;
440 rotate[8] = 1;
441
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442 ROT_DEBUG(dump_mat("rotate", rotate));
443
444 ROT_DEBUG(fprintf(stderr, "cos %g sin %g\n", rotate[0], rotate[1]));
445
446 x1 = ceil(fabs(src->xsize * rotate[0] + src->ysize * rotate[1]) - 0.0001);
447 x2 = ceil(fabs(src->xsize * rotate[0] - src->ysize * rotate[1]) - 0.0001);
448 y1 = ceil(fabs(src->xsize * rotate[3] + src->ysize * rotate[4]) - 0.0001);
449 y2 = ceil(fabs(src->xsize * rotate[3] - src->ysize * rotate[4]) - 0.0001);
450 ROT_DEBUG(fprintf(stderr, "x1 y1 " i_DFp " x2 y2 " i_DFp "\n", i_DFcp(x1, y1), i_DFcp(x2, y2)));
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451 newxsize = x1 > x2 ? x1 : x2;
452 newysize = y1 > y2 ? y1 : y2;
453 /* translate the centre back to the center of the image */
454 xlate2[0] = 1;
289d65f4 455 xlate2[2] = -(newxsize-1)/2.0;
faa9b3e7 456 xlate2[4] = 1;
289d65f4 457 xlate2[5] = -(newysize-1)/2.0;
faa9b3e7 458 xlate2[8] = 1;
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459
460 ROT_DEBUG(dump_mat("xlate2", xlate2));
461
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462 i_matrix_mult(temp, xlate1, rotate);
463 i_matrix_mult(matrix, temp, xlate2);
464
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465 ROT_DEBUG(dump_mat("matrxi", matrix));
466
0d3b936e 467 return i_matrix_transform_bg(src, newxsize, newysize, matrix, backp, fbackp);
faa9b3e7 468}
b8c2033e 469
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470i_img *i_rotate_exact(i_img *src, double amount) {
471 return i_rotate_exact_bg(src, amount, NULL, NULL);
472}
473
474
b8c2033e
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475/*
476=back
477
478=head1 AUTHOR
479
480Tony Cook <tony@develop-help.com>
481
482=head1 SEE ALSO
483
484Imager(3)
485
486=cut
487*/