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authormarha <marha@users.sourceforge.net>2012-07-31 10:17:14 +0200
committermarha <marha@users.sourceforge.net>2012-07-31 10:17:14 +0200
commit83da3ad0287bc51cd16ee6911fe73dc98ebe000b (patch)
tree48d48590a0b0a3770006aeda8ec2b2a45054d1f1 /pixman/demos/srgb-test.c
parent00e30605ffc7ac3cf1a091ff2c1f46cfefb780d7 (diff)
parentbd27b3d008b0abf9ae2edcb127302728808533e4 (diff)
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Merge remote-tracking branch 'origin/released'
Diffstat (limited to 'pixman/demos/srgb-test.c')
-rw-r--r--pixman/demos/srgb-test.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/pixman/demos/srgb-test.c b/pixman/demos/srgb-test.c
new file mode 100644
index 000000000..bc073491e
--- /dev/null
+++ b/pixman/demos/srgb-test.c
@@ -0,0 +1,96 @@
+#include <math.h>
+
+#include "pixman.h"
+#include "gtk-utils.h"
+
+static uint32_t
+linear_argb_to_premult_argb (float a,
+ float r,
+ float g,
+ float b)
+{
+ r *= a;
+ g *= a;
+ b *= a;
+ return (uint32_t) (a * 255.0f + 0.5f) << 24
+ | (uint32_t) (r * 255.0f + 0.5f) << 16
+ | (uint32_t) (g * 255.0f + 0.5f) << 8
+ | (uint32_t) (b * 255.0f + 0.5f) << 0;
+}
+
+static float
+lin2srgb (float linear)
+{
+ if (linear < 0.0031308f)
+ return linear * 12.92f;
+ else
+ return 1.055f * powf (linear, 1.0f/2.4f) - 0.055f;
+}
+
+static uint32_t
+linear_argb_to_premult_srgb_argb (float a,
+ float r,
+ float g,
+ float b)
+{
+ r = lin2srgb (r * a);
+ g = lin2srgb (g * a);
+ b = lin2srgb (b * a);
+ return (uint32_t) (a * 255.0f + 0.5f) << 24
+ | (uint32_t) (r * 255.0f + 0.5f) << 16
+ | (uint32_t) (g * 255.0f + 0.5f) << 8
+ | (uint32_t) (b * 255.0f + 0.5f) << 0;
+}
+
+int
+main (int argc, char **argv)
+{
+#define WIDTH 400
+#define HEIGHT 200
+ int y, x, p;
+ float alpha;
+
+ uint32_t *dest = malloc (WIDTH * HEIGHT * 4);
+ uint32_t *src1 = malloc (WIDTH * HEIGHT * 4);
+ pixman_image_t *dest_img, *src1_img;
+
+ dest_img = pixman_image_create_bits (PIXMAN_a8r8g8b8_sRGB,
+ WIDTH, HEIGHT,
+ dest,
+ WIDTH * 4);
+ src1_img = pixman_image_create_bits (PIXMAN_a8r8g8b8,
+ WIDTH, HEIGHT,
+ src1,
+ WIDTH * 4);
+
+ for (y = 0; y < HEIGHT; y ++)
+ {
+ p = WIDTH * y;
+ for (x = 0; x < WIDTH; x ++)
+ {
+ alpha = (float) x / WIDTH;
+ src1[p + x] = linear_argb_to_premult_argb (alpha, 1, 0, 1);
+ dest[p + x] = linear_argb_to_premult_srgb_argb (1-alpha, 0, 1, 0);
+ }
+ }
+
+ pixman_image_composite (PIXMAN_OP_ADD, src1_img, NULL, dest_img,
+ 0, 0, 0, 0, 0, 0, WIDTH, HEIGHT);
+ pixman_image_unref (src1_img);
+ free (src1);
+
+ pixman_image_unref (dest_img);
+
+ /* Now that the picture has been correctly constructed,
+ * we hand it over to our support library as argb which it
+ * knows how to handle (it doesn't understand _sRGB format). */
+ dest_img = pixman_image_create_bits (PIXMAN_a8r8g8b8,
+ WIDTH, HEIGHT,
+ dest,
+ WIDTH * 4);
+ show_image (dest_img);
+ pixman_image_unref (dest_img);
+ free (dest);
+
+ return 0;
+}