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	blind-gauss-blur.c - blind - suckless command-line video editing utility
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	blind-gauss-blur.c (10542B)
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	1 /* See LICENSE file for copyright and license details. */
	2 #include "common.h"
	3
	4 USAGE("[-j jobs] [-s spread \| -s 'auto'] [-acghvy] sd-stream")
	5
	6 static int chroma = 0;
	7 static int noalpha = 0;
	8 static int glow = 0;
	9 static int vertical = 0;
	10 static int horizontal = 0;
	11 static int measure_y_only = 0;
	12 static int auto_spread = 0;
	13 static size_t jobs = 1;
	14 static size_t spread = 0;
	15 static void *original = NULL;
	16
	17 /*
	18 * This is not a regular simple gaussian blur implementation.
	19 * This implementation is able to apply different levels of
	20 * blur on different pixels. It's therefore written a bit
	21 * oddly. Instead of going through each pixel and calculate
	22 * the new value for each pixel, it goes through each pixel
	23 * and smears it out to the other pixels.
	24 */
	25
	26 #define BLUR_PIXEL_PROLOGUE(TYPE, DIR)\
	27 if (sig[i1][3] == 0)\
	28 goto no_blur_##DIR;\
	29 if (chroma \|\| measure_y_only) {\
	30 k[0] = sig[i1][1] * sig[i1][3];\
	31 if (auto_spread)\
	32 spread = k[0] > 0 ? (size_t)(k[0] * 3 + (TYPE)0.…
	33 blur[2] = blur[0] = k[0] > 0;\
	34 c[0] = k[0] = k[0] 2, c[0] = sqrt(c[0] * (TYPE)M_PI);\
	35 k[0] = 1 / -k[0], c[0] = 1 / c[0];\
	36 if (chroma) {\
	37 k[2] = k[0];\
	38 c[2] = c[0];\
	39 c[1] = k[1] = 0;\
	40 blur[1] = 0;\
	41 } else {\
	42 k[2] = k[1] = k[0];\
	43 c[2] = c[1] = c[0];\
	44 blur[1] = blur[0];\
	45 }\
	46 } else {\
	47 if (auto_spread)\
	48 spread = 0;\
	49 for (i = 0; i < 3; i++) {\
	50 k[i] = sig[i1][i] * sig[i1][3];\
	51 if (auto_spread && k[i] > 0 && spread < (size_t)…
	52 spread = (size_t)(k[i] * 3 + (TYPE)0.5);\
	53 blur[i] = k[i] > 0;\
	54 c[i] = k[i] = k[i] 2, c[i] = sqrt(c[i] * (TYP…
	55 k[i] = 1 / -k[i], c[i] = 1 / c[i];\
	56 }\
	57 }\
	58 if (blur[0] + blur[1] + blur[2] == 0)\
	59 goto no_blur_##DIR;\
	60 if (auto_spread && spread < 1)\
	61 spread = 1;
	62
	63 #define BLUR_PIXEL(TYPE, START, LOOP, DISTANCE)\
	64 if (k[0] == k[1] && k[1] == k[2]) {\
	65 START;\
	66 for (LOOP) {\
	67 d = (TYPE)(DISTANCE);\
	68 d *= d;\
	69 m = c[0] * exp(d * k[0]);\
	70 img[i2][0] += clr[i1][0] * m;\
	71 img[i2][1] += clr[i1][1] * m;\
	72 img[i2][2] += clr[i1][2] * m;\
	73 img[i2][3] += clr[i1][3] * m;\
	74 }\
	75 } else {\
	76 blurred = 0;\
	77 for (i = 0; i < 3; i++) {\
	78 if (blur[i])\
	79 blurred += 1;\
	80 else\
	81 img[i1][i] += clr[i1][i];\
	82 }\
	83 for (i = 0; i < 3; i++) {\
	84 if (!blur[i])\
	85 continue;\
	86 START;\
	87 for (LOOP) {\
	88 d = (TYPE)(DISTANCE);\
	89 d *= d;\
	90 m = c[i] * exp(d * k[i]);\
	91 img[i2][i] += clr[i1][i] * m;\
	92 img[i2][3] += clr[i1][3] * m / (TYPE)blu…
	93 }\
	94 }\
	95 }
	96
	97 #define BLUR_PIXEL_EPILOGUE(DIR)\
	98 continue;\
	99 no_blur_##DIR:\
	100 img[i1][0] = clr[i1][0];\
	101 img[i1][1] = clr[i1][1];\
	102 img[i1][2] = clr[i1][2];\
	103 img[i1][3] = clr[i1][3];
	104
	105 #define BLUR(TYPE, DIR, SETSTART, SETEND, START, LOOP, DISTANCE)\
	106 do {\
	107 memset(img, 0, colour->frame_size);\
	108 start = 0, end = colour->height;\
	109 is_master = efork_jobs(&start, &end, jobs, &children);\
	110 i1 = start * colour->width;\
	111 for (y1 = start; y1 < end; y1++) {\
	112 for (x1 = 0; x1 < colour->width; x1++, i1++) {\
	113 BLUR_PIXEL_PROLOGUE(TYPE, DIR);\
	114 if (spread) {\
	115 SETSTART;\
	116 SETEND;\
	117 }\
	118 BLUR_PIXEL(TYPE, START, LOOP, DISTANCE);\
	119 BLUR_PIXEL_EPILOGUE(DIR);\
	120 }\
	121 }\
	122 ejoin_jobs(is_master, children);\
	123 } while (0)
	124
	125 #define PROCESS(TYPE)\
	126 do {\
	127 typedef TYPE pixel_t[4];\
	128 \
	129 pixel_t restrict clr = (pixel_t )cbuf;\
	130 pixel_t restrict sig = (pixel_t )sbuf;\
	131 pixel_t *restrict orig = original;\
	132 pixel_t img = (pixel_t )output;\
	133 pixel_t c, k;\
	134 size_t x1, y1, i1, x2, y2, i2;\
	135 TYPE d, m;\
	136 int i, blurred, blur[3] = {0, 0, 0};\
	137 size_t start, end, x2start, x2end, y2start, y2end;\
	138 int is_master;\
	139 pid_t *children;\
	140 \
	141 y2start = x2start = 0;\
	142 x2end = colour->width;\
	143 y2end = colour->height;\
	144 \
	145 if (glow)\
	146 memcpy(orig, clr, colour->frame_size);\
	147 if (chroma \|\| !noalpha) {\
	148 start = 0, end = colour->height;\
	149 is_master = efork_jobs(&start, &end, jobs, &chil…
	150 \
	151 /* premultiply alpha channel */\
	152 if (!noalpha) {\
	153 i1 = start * colour->width;\
	154 for (y1 = start; y1 < end; y1++) {\
	155 for (x1 = 0; x1 < colour->width;…
	156 clr[i1][0] *= clr[i1][3]…
	157 clr[i1][1] *= clr[i1][3]…
	158 clr[i1][2] *= clr[i1][3]…
	159 }\
	160 }\
	161 }\
	162 \
	163 /* store original image */\
	164 if (glow) {\
	165 i1 = start * colour->width;\
	166 memcpy(orig + i1, clr + i1, (end - start…
	167 }\
	168 \
	169 /* convert colour model */\
	170 if (chroma) {\
	171 i1 = start * colour->width;\
	172 for (y1 = start; y1 < end; y1++) {\
	173 for (x1 = 0; x1 < colour->width;…
	174 clr[i1][0] = clr[i1][0] …
	175 clr[i1][2] = clr[i1][2] …
	176 /*
	177 * Explaination:
	178 * Y is the luma and (…
	179 * is the chroma (acco…
	180 * is the white point.
	181 */\
	182 }\
	183 }\
	184 }\
	185 /* Conversion makes no difference if blur is app…
	186 * parameters:
	187 *
	188 * Gaussian blur:
	189 *
	190 * ∞ ∞
	191 * ⌠ ⌠ V(x,y) −((x−x�…
	192 * V′ (x₀,y₀) = │ │ ────�…
	193 * σ ⌡ ⌡ 2πσ²
	194 * −∞ −∞
	195 *
	196 * With linear transformation, F:
	197 *
	198 * ∞ ∞
	199 * ⌠ ⌠ F(V(x,y)) −((…
	200 * V′ (x₀,y₀) = F⁻¹ │ │ ──�…
	201 * σ ⌡ ⌡ 2πσ²
	202 * −∞ −∞
	203 *
	204 * ∞ ∞
	205 * ⌠ ⌠ ⎛V(x,y) −(…
	206 * V′ (x₀,y₀) = F⁻¹ │ │ F⎜─…
	207 * σ ⌡ ⌡ ⎝ 2πσ² …
	208 * −∞ −∞
	209 *
	210 * ∞ ∞
	211 * ⌠ ⌠ V(x,y) �…
	212 * V′ (x₀,y₀) = (F⁻¹ ∘ F) │ │…
	213 * σ ⌡ ⌡ 2πσ²
	214 * −∞ −∞
	215 *
	216 * ∞ ∞
	217 * ⌠ ⌠ V(x,y) −((x−x�…
	218 * V′ (x₀,y₀) = │ │ ────�…
	219 * σ ⌡ ⌡ 2πσ²
	220 * −∞ −∞
	221 *
	222 * Just like expected, the colour space should n…
	223 * result of guassian blur as long as it is line…
	224 */\
	225 \
	226 ejoin_jobs(is_master, children);\
	227 }\
	228 \
	229 /* blur */\
	230 if (horizontal)\
	231 BLUR(TYPE, horizontal,\
	232 x2start = spread > x1 ? 0 : x1 - spread,\
	233 x2end = spread + 1 > colour->width - x1 ? c…
	234 i2 = y1 * colour->width + x2start,\
	235 x2 = x2start; x2 < x2end; (x2++, i2++),\
	236 (ssize_t)x1 - (ssize_t)x2);\
	237 if (horizontal && vertical)\
	238 memcpy(clr, img, colour->frame_size);\
	239 if (vertical)\
	240 BLUR(TYPE, vertical,\
	241 y2start = spread > y1 ? 0 : y1 - spread,\
	242 y2end = spread + 1 > colour->height - y1 ? …
	243 i2 = y2start * colour->width + x1,\
	244 y2 = y2start; y2 < y2end; (y2++, i2 += colo…
	245 (ssize_t)y1 - (ssize_t)y2);\
	246 \
	247 start = 0, end = colour->height;\
	248 is_master = efork_jobs(&start, &end, jobs, &children);\
	249 \
	250 /* convert back to CIE XYZ */\
	251 if (chroma) {\
	252 i1 = start * colour->width;\
	253 for (y1 = start; y1 < end; y1++) {\
	254 for (x1 = 0; x1 < colour->width; x1++, i…
	255 img[i1][0] = (img[i1][0] + img[i…
	256 img[i1][2] = (img[i1][2] + img[i…
	257 }\
	258 }\
	259 }\
	260 \
	261 /* apply glow */\
	262 if (glow) {\
	263 i1 = start * colour->width;\
	264 for (y1 = start; y1 < end; y1++) {\
	265 for (x1 = 0; x1 < colour->width; x1++, i…
	266 img[i1][0] += orig[i1][0];\
	267 img[i1][1] += orig[i1][1];\
	268 img[i1][2] += orig[i1][2];\
	269 img[i1][3] += orig[i1][3];\
	270 }\
	271 }\
	272 }\
	273 \
	274 /* unpremultiply alpha channel */\
	275 i1 = start * colour->width;\
	276 for (y1 = start; y1 < end; y1++) {\
	277 for (x1 = 0; x1 < colour->width; x1++, i1++) {\
	278 if (img[i1][3] != 0)\
	279 continue;\
	280 img[i1][0] /= img[i1][3];\
	281 img[i1][1] /= img[i1][3];\
	282 img[i1][2] /= img[i1][3];\
	283 }\
	284 }\
	285 \
	286 /* ensure the video if opaque if -a was used */\
	287 if (noalpha) {\
	288 i1 = start * colour->width;\
	289 for (y1 = start; y1 < end; y1++)\
	290 for (x1 = 0; x1 < colour->width; x1++, i…
	291 img[i1][3] = 1;\
	292 }\
	293 \
	294 ejoin_jobs(is_master, children);\
	295 \
	296 (void) sigma;\
	297 } while (0)
	298
	299 static void
	300 process_lf(char restrict output, char restrict cbuf, char *restrict sb…
	301 struct stream colour, struct stream sigma)
	302 {
	303 PROCESS(double);
	304 }
	305
	306 static void
	307 process_f(char restrict output, char restrict cbuf, char *restrict sbu…
	308 struct stream colour, struct stream sigma)
	309 {
	310 PROCESS(float);
	311 }
	312
	313 int
	314 main(int argc, char *argv[])
	315 {
	316 struct stream colour, sigma;
	317 char *arg;
	318 void (process)(char restrict output, char *restrict cbuf, char…
	319 struct stream colour, struct stream sigma);
	320
	321 ARGBEGIN {
	322 case 'a':
	323 noalpha = 1;
	324 break;
	325 case 'c':
	326 chroma = 1;
	327 break;
	328 case 'g':
	329 glow = 1;
	330 break;
	331 case 'h':
	332 horizontal = 1;
	333 break;
	334 case 'v':
	335 vertical = 1;
	336 break;
	337 case 'y':
	338 measure_y_only = 1;
	339 break;
	340 case 'j':
	341 jobs = etozu_flag('j', UARGF(), 1, SHRT_MAX);
	342 break;
	343 case 's':
	344 arg = UARGF();
	345 if (!strcmp(arg, "auto"))
	346 auto_spread = 1;
	347 else
	348 spread = etozu_flag('s', arg, 1, SIZE_MAX);
	349 break;
	350 default:
	351 usage();
	352 } ARGEND;
	353
	354 if (argc != 1)
	355 usage();
	356
	357 if (!vertical && !horizontal)
	358 vertical = horizontal = 1;
	359
	360 eopen_stream(&colour, NULL);
	361 eopen_stream(&sigma, argv[0]);
	362
	363 SELECT_PROCESS_FUNCTION(&colour);
	364 CHECK_CHANS(&colour, == 3, == (measure_y_only ? 1 : colour.luma_…
	365 CHECK_N_CHAN(&colour, 4, 4);
	366
	367 echeck_compat(&colour, &sigma);
	368
	369 if (jobs > colour.height)
	370 jobs = colour.height;
	371
	372 if (glow)
	373 original = emalloc(colour.frame_size);
	374
	375 fprint_stream_head(stdout, &colour);
	376 efflush(stdout, "<stdout>");
	377 process_each_frame_two_streams(&colour, &sigma, STDOUT_FILENO, "…
	378 free(original);
	379 return 0;
	380 }