4 rotate.im - implements image rotations
8 i_img *i_rotate90(i_img *src, int degrees)
12 Implements basic 90 degree rotations of an image.
14 Other rotations will be added as tuits become available.
21 #include <math.h> /* for floor() */
25 i_img *i_rotate90(i_img *src, int degrees) {
32 /* essentially the same as flipxy(..., 2) except that it's not
34 targ = i_sametype(src, src->xsize, src->ysize);
35 if (src->type == i_direct_type) {
37 IM_COLOR *vals = mymalloc(src->xsize * sizeof(IM_COLOR));
38 for (y = 0; y < src->ysize; ++y) {
40 IM_GLIN(src, 0, src->xsize, y, vals);
41 for (x = 0; x < src->xsize/2; ++x) {
43 vals[x] = vals[src->xsize - x - 1];
44 vals[src->xsize - x - 1] = tmp;
46 IM_PLIN(targ, 0, src->xsize, src->ysize - y - 1, vals);
52 i_palidx *vals = mymalloc(src->xsize * sizeof(i_palidx));
54 for (y = 0; y < src->ysize; ++y) {
56 i_gpal(src, 0, src->xsize, y, vals);
57 for (x = 0; x < src->xsize/2; ++x) {
59 vals[x] = vals[src->xsize - x - 1];
60 vals[src->xsize - x - 1] = tmp;
62 i_ppal(targ, 0, src->xsize, src->ysize - y - 1, vals);
70 else if (degrees == 270 || degrees == 90) {
71 i_img_dim tx, txstart, txinc;
72 i_img_dim ty, tystart, tyinc;
77 tystart = src->xsize-1;
81 txstart = src->ysize-1;
86 targ = i_sametype(src, src->ysize, src->xsize);
87 if (src->type == i_direct_type) {
89 IM_COLOR *vals = mymalloc(src->xsize * sizeof(IM_COLOR));
92 for (y = 0; y < src->ysize; ++y) {
93 IM_GLIN(src, 0, src->xsize, y, vals);
95 for (x = 0; x < src->xsize; ++x) {
96 IM_PPIX(targ, tx, ty, vals+x);
105 i_palidx *vals = mymalloc(src->xsize * sizeof(i_palidx));
108 for (y = 0; y < src->ysize; ++y) {
109 i_gpal(src, 0, src->xsize, y, vals);
111 for (x = 0; x < src->xsize; ++x) {
112 i_ppal(targ, tx, tx+1, ty, vals+x);
122 i_push_error(0, "i_rotate90() only rotates at 90, 180, or 270 degrees");
127 /* linear interpolation */
128 static i_color interp_i_color(i_color before, i_color after, double pos,
134 if (channels == 1 || channels == 3) {
135 for (ch = 0; ch < channels; ++ch)
136 out.channel[ch] = ((1-pos) * before.channel[ch] + pos * after.channel[ch]) + 0.5;
139 int total_cover = (1-pos) * before.channel[channels-1]
140 + pos * after.channel[channels-1];
142 total_cover = I_LIMIT_8(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;
148 for (ch = 0; ch < channels-1; ++ch) {
149 int out_level = ((1-pos) * before.channel[ch] * before_alpha +
150 pos * after.channel[ch] * after_alpha) / total_alpha + 0.5;
152 out.channel[ch] = I_LIMIT_8(out_level);
156 for (ch = 0; ch < channels-1; ++ch)
160 out.channel[channels-1] = total_cover;
166 /* hopefully this will be inlined (it is with -O3 with gcc 2.95.4) */
167 /* linear interpolation */
168 static i_fcolor interp_i_fcolor(i_fcolor before, i_fcolor after, double pos,
174 if (channels == 1 || channels == 3) {
175 for (ch = 0; ch < channels; ++ch)
176 out.channel[ch] = (1-pos) * before.channel[ch] + pos * after.channel[ch];
179 double total_cover = (1-pos) * before.channel[channels-1]
180 + pos * after.channel[channels-1];
182 total_cover = I_LIMIT_DOUBLE(total_cover);
184 double before_alpha = before.channel[channels-1];
185 double after_alpha = after.channel[channels-1];
186 double total_alpha = before_alpha * (1-pos) + after_alpha * pos;
188 for (ch = 0; ch < channels-1; ++ch) {
189 double out_level = ((1-pos) * before.channel[ch] * before_alpha +
190 pos * after.channel[ch] * after_alpha) / total_alpha;
192 out.channel[ch] = I_LIMIT_DOUBLE(out_level);
196 for (ch = 0; ch < channels-1; ++ch)
200 out.channel[channels-1] = total_cover;
206 i_img *i_matrix_transform_bg(i_img *src, i_img_dim xsize, i_img_dim ysize, const double *matrix,
207 const i_color *backp, const i_fcolor *fbackp) {
208 i_img *result = i_sametype(src, xsize, ysize);
214 if (src->type == i_direct_type) {
216 IM_COLOR *vals = mymalloc(xsize * sizeof(IM_COLOR));
224 for (ch = 0; ch < src->channels; ++ch) {
226 fsamp = fbackp->channel[ch];
227 back.channel[ch] = fsamp < 0 ? 0 : fsamp > 1 ? 255 : fsamp * 255;
231 #define interp_i_color interp_i_fcolor
236 for (ch = 0; ch < src->channels; ++ch)
237 back.channel[ch] = backp->channel[ch] / 255.0;
241 for (ch = 0; ch < src->channels; ++ch)
242 back.channel[ch] = 0;
245 for (y = 0; y < ysize; ++y) {
246 for (x = 0; x < xsize; ++x) {
247 /* dividing by sz gives us the ability to do perspective
249 sz = x * matrix[6] + y * matrix[7] + matrix[8];
250 if (fabs(sz) > 0.0000001) {
251 sx = (x * matrix[0] + y * matrix[1] + matrix[2]) / sz;
252 sy = (x * matrix[3] + y * matrix[4] + matrix[5]) / sz;
258 /* anything outside these ranges is either a broken co-ordinate
259 or outside the source */
260 if (fabs(sz) > 0.0000001
261 && sx >= -1 && sx < src->xsize
262 && sy >= -1 && sy < src->ysize) {
263 i_img_dim bx = floor(sx);
264 i_img_dim by = floor(sy);
266 ROT_DEBUG(fprintf(stderr, "map " i_DFp " to %g,%g\n", i_DFcp(x, y), sx, sy));
271 ROT_DEBUG(fprintf(stderr, " both non-int\n"));
272 for (i = 0; i < 2; ++i)
273 for (j = 0; j < 2; ++j)
274 if (IM_GPIX(src, bx+i, by+j, &c[j][i]))
276 for (j = 0; j < 2; ++j)
277 ci2[j] = interp_i_color(c[j][0], c[j][1], sx, src->channels);
278 vals[x] = interp_i_color(ci2[0], ci2[1], sy, src->channels);
282 ROT_DEBUG(fprintf(stderr, " y int, x non-int\n"));
283 for (i = 0; i < 2; ++i)
284 if (IM_GPIX(src, bx+i, sy, ci2+i))
286 vals[x] = interp_i_color(ci2[0], ci2[1], sx, src->channels);
290 if (sy != (i_img_dim)sy) {
292 ROT_DEBUG(fprintf(stderr, " x int, y non-int\n"));
293 for (i = 0; i < 2; ++i)
294 if (IM_GPIX(src, bx, by+i, ci2+i))
296 vals[x] = interp_i_color(ci2[0], ci2[1], sy, src->channels);
299 ROT_DEBUG(fprintf(stderr, " both int\n"));
300 /* all the world's an integer */
301 if (IM_GPIX(src, sx, sy, vals+x))
310 IM_PLIN(result, 0, xsize, y, vals);
313 #undef interp_i_color
317 /* don't interpolate for a palette based image */
318 i_palidx *vals = mymalloc(xsize * sizeof(i_palidx));
320 int minval = 256 * 4;
329 for (ch = 0; ch < src->channels; ++ch) {
330 fsamp = fbackp->channel[ch];
331 want_back.channel[ch] = fsamp < 0 ? 0 : fsamp > 1 ? 255 : fsamp * 255;
335 for (ch = 0; ch < src->channels; ++ch)
336 want_back.channel[ch] = 0;
339 /* find the closest color */
340 for (i = 0; i < i_colorcount(src); ++i) {
343 i_getcolors(src, i, &temp, 1);
345 for (ch = 0; ch < src->channels; ++ch) {
346 tempval += abs(want_back.channel[ch] - temp.channel[ch]);
348 if (tempval < minval) {
354 for (y = 0; y < ysize; ++y) {
355 for (x = 0; x < xsize; ++x) {
356 /* dividing by sz gives us the ability to do perspective
358 sz = x * matrix[6] + y * matrix[7] + matrix[8];
359 if (abs(sz) > 0.0000001) {
360 sx = (x * matrix[0] + y * matrix[1] + matrix[2]) / sz;
361 sy = (x * matrix[3] + y * matrix[4] + matrix[5]) / sz;
367 /* anything outside these ranges is either a broken co-ordinate
368 or outside the source */
369 if (abs(sz) > 0.0000001
370 && sx >= -0.5 && sx < src->xsize-0.5
371 && sy >= -0.5 && sy < src->ysize-0.5) {
373 /* all the world's an integer */
374 ix = (i_img_dim)(sx+0.5);
375 iy = (i_img_dim)(sy+0.5);
376 if (!i_gpal(src, ix, ix+1, iy, vals+x))
383 i_ppal(result, 0, xsize, y, vals);
391 i_img *i_matrix_transform(i_img *src, i_img_dim xsize, i_img_dim ysize, const double *matrix) {
392 return i_matrix_transform_bg(src, xsize, ysize, matrix, NULL, NULL);
396 i_matrix_mult(double *dest, const double *left, const double *right) {
400 for (i = 0; i < 3; ++i) {
401 for (j = 0; j < 3; ++j) {
403 for (k = 0; k < 3; ++k) {
404 accum += left[3*i+k] * right[3*k+j];
411 #define numfmt "%23g"
413 ROT_DEBUG(static void dump_mat(const char *name, double *f) {
414 fprintf(stderr, "%s:\n " numfmt " " numfmt " " numfmt "\n"
415 " " numfmt " " numfmt " " numfmt "\n"
416 " " numfmt " " numfmt " " numfmt "\n",
417 name, f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8]);
420 i_img *i_rotate_exact_bg(i_img *src, double amount,
421 const i_color *backp, const i_fcolor *fbackp) {
422 double xlate1[9] = { 0 };
424 double xlate2[9] = { 0 };
425 double temp[9], matrix[9];
426 i_img_dim x1, x2, y1, y2, newxsize, newysize;
428 ROT_DEBUG(fprintf(stderr, "rotate angle %.20g\n", amount));
430 /* first translate the centre of the image to (0,0) */
432 xlate1[2] = (src->xsize-1)/2.0;
434 xlate1[5] = (src->ysize-1)/2.0;
437 ROT_DEBUG(dump_mat("xlate1", xlate1));
439 /* rotate around (0.0) */
440 rotate[0] = cos(amount);
441 rotate[1] = sin(amount);
443 rotate[3] = -rotate[1];
444 rotate[4] = rotate[0];
450 ROT_DEBUG(dump_mat("rotate", rotate));
452 ROT_DEBUG(fprintf(stderr, "cos %g sin %g\n", rotate[0], rotate[1]));
454 x1 = ceil(fabs(src->xsize * rotate[0] + src->ysize * rotate[1]) - 0.0001);
455 x2 = ceil(fabs(src->xsize * rotate[0] - src->ysize * rotate[1]) - 0.0001);
456 y1 = ceil(fabs(src->xsize * rotate[3] + src->ysize * rotate[4]) - 0.0001);
457 y2 = ceil(fabs(src->xsize * rotate[3] - src->ysize * rotate[4]) - 0.0001);
458 ROT_DEBUG(fprintf(stderr, "x1 y1 " i_DFp " x2 y2 " i_DFp "\n", i_DFcp(x1, y1), i_DFcp(x2, y2)));
459 newxsize = x1 > x2 ? x1 : x2;
460 newysize = y1 > y2 ? y1 : y2;
461 /* translate the centre back to the center of the image */
463 xlate2[2] = -(newxsize-1)/2.0;
465 xlate2[5] = -(newysize-1)/2.0;
468 ROT_DEBUG(dump_mat("xlate2", xlate2));
470 i_matrix_mult(temp, xlate1, rotate);
471 i_matrix_mult(matrix, temp, xlate2);
473 ROT_DEBUG(dump_mat("matrxi", matrix));
475 return i_matrix_transform_bg(src, newxsize, newysize, matrix, backp, fbackp);
478 i_img *i_rotate_exact(i_img *src, double amount) {
479 return i_rotate_exact_bg(src, amount, NULL, NULL);
488 Tony Cook <tony@develop-help.com>