Hija,
this is my suggested patch for getting the speeds improvements as mentioned in the other thread by having a thread-local PRNG initialized with a seed from the still existing blend tool local RNG.
It looks bigger than it is because I took the liberty to remove the nasty special casing on the existence of the RNG inside the innermost loop because we now have it outside already.
There seems to be more room for obvious optimisations in the loops. Also I would recommend splitting the two cases into two separate functions to make the code easier to read, and remove more conditionals.
PS: If this is okay, I'd do exactly the same for the gray blending stuff...
diff -u -r1.155 gimpdrawable-blend.c
--- app/core/gimpdrawable-blend.c 26 Feb 2005 23:55:49 -0000 1.155
+++ app/core/gimpdrawable-blend.c 27 Feb 2005 14:55:36 -0000
@@ -1051,7 +1051,68 @@
gint endx = PR->x + PR->w;
gint endy = PR->y + PR->h;
gint x, y;
+
+ if (rbd->dither_rand)
+ {
+ GRand *localrand = g_rand_new_with_seed (g_rand_int (rbd->dither_rand));
+
+ for (y = PR->y; y < endy; y++)
+ {
+ for (x = PR->x; x < endx; x++)
+ {
+ GimpRGB color;
+ gdouble dither_prob;
+ gdouble ftmp;
+ gint itmp;
+
+ gradient_render_pixel (x, y, &color, rbd);
+
+ ftmp = color.r * 255.0;
+ itmp = ftmp;
+ dither_prob = ftmp - itmp;
+
+ if (g_rand_double (localrand) < dither_prob)
+ color.r += (1.0 / 255.0);
+
+ ftmp = color.g * 255.0;
+ itmp = ftmp;
+ dither_prob = ftmp - itmp;
+
+ if (g_rand_double (localrand) < dither_prob)
+ color.g += (1.0 / 255.0);
+
+ ftmp = color.b * 255.0;
+ itmp = ftmp;
+ dither_prob = ftmp - itmp;
+ if (g_rand_double (localrand) < dither_prob)
+ color.b += (1.0 / 255.0);
+
+ ftmp = color.a * 255.0;
+ itmp = ftmp;
+ dither_prob = ftmp - itmp;
+
+ if (g_rand_double (localrand) < dither_prob)
+ color.a += (1.0 / 255.0);
+
+ if (color.r > 1.0) color.r = 1.0;
+ if (color.g > 1.0) color.g = 1.0;
+ if (color.b > 1.0) color.b = 1.0;
+ if (color.a > 1.0) color.a = 1.0;
+
+ *dest++ = color.r * 255.0;
+ *dest++ = color.g * 255.0;
+ *dest++ = color.b * 255.0;
+ *dest++ = color.a * 255.0;
+ }
+ }
+
+ g_rand_free (localrand);
+
+ return;
+ }
+
+ /* Fall-through for non-dithering case */
for (y = PR->y; y < endy; y++)
{
for (x = PR->x; x < endx; x++)
@@ -1059,46 +1120,6 @@
GimpRGB color; gradient_render_pixel (x, y, &color, rbd);
-
- if (rbd->dither_rand)
- {
- gdouble dither_prob;
- gdouble ftmp;
- gint itmp;
-
- ftmp = color.r * 255.0;
- itmp = ftmp;
- dither_prob = ftmp - itmp;
-
- if (g_rand_double (rbd->dither_rand) < dither_prob)
- color.r += (1.0 / 255.0);
-
- ftmp = color.g * 255.0;
- itmp = ftmp;
- dither_prob = ftmp - itmp;
-
- if (g_rand_double (rbd->dither_rand) < dither_prob)
- color.g += (1.0 / 255.0);
-
- ftmp = color.b * 255.0;
- itmp = ftmp;
- dither_prob = ftmp - itmp;
-
- if (g_rand_double (rbd->dither_rand) < dither_prob)
- color.b += (1.0 / 255.0);
-
- ftmp = color.a * 255.0;
- itmp = ftmp;
- dither_prob = ftmp - itmp;
-
- if (g_rand_double (rbd->dither_rand) < dither_prob)
- color.a += (1.0 / 255.0);
-
- if (color.r > 1.0) color.r = 1.0;
- if (color.g > 1.0) color.g = 1.0;
- if (color.b > 1.0) color.b = 1.0;
- if (color.a > 1.0) color.a = 1.0;
- } *dest++ = color.r * 255.0;
*dest++ = color.g * 255.0;
Servus, Daniel
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