From: Søren Sandmann Pedersen <s...@redhat.com>
This program displays a linear gradient from blue to yellow. Due to
limited precision in pixman-gradient-walker.c, it currently has some
ugly artefacts that gives it a 'brushed metal' appearance.
---
demos/Makefile.am | 2 +
demos/linear-gradient.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 52 insertions(+), 0 deletions(-)
create mode 100644 demos/linear-gradient.c
diff --git a/demos/Makefile.am b/demos/Makefile.am
index 5f53407..9be9ab6 100644
--- a/demos/Makefile.am
+++ b/demos/Makefile.am
@@ -15,6 +15,7 @@ DEMOS = \
composite-test \
gradient-test \
radial-test \
+ linear-gradient \
conical-test \
alpha-test \
screen-test \
@@ -38,6 +39,7 @@ trap_test_SOURCES = trap-test.c $(GTK_UTILS)
screen_test_SOURCES = screen-test.c $(GTK_UTILS)
convolution_test_SOURCES = convolution-test.c $(GTK_UTILS)
radial_test_SOURCES = radial-test.c $(GTK_UTILS)
+linear_gradient_SOURCES = linear-gradient.c $(GTK_UTILS)
conical_test_SOURCES = conical-test.c $(GTK_UTILS)
tri_test_SOURCES = tri-test.c $(GTK_UTILS)
checkerboard_SOURCES = checkerboard.c $(GTK_UTILS)
diff --git a/demos/linear-gradient.c b/demos/linear-gradient.c
new file mode 100644
index 0000000..46433a6
--- /dev/null
+++ b/demos/linear-gradient.c
@@ -0,0 +1,50 @@
+#include "../test/utils.h"
+#include "gtk-utils.h"
+
+#define WIDTH 1024
+#define HEIGHT 640
+
+int
+main (int argc, char **argv)
+{
+ pixman_image_t *src_img, *dest_img;
+ pixman_gradient_stop_t stops[] = {
+ { 0x00000, { 0x0000, 0x0000, 0x4444, 0xdddd } },
+ { 0x10000, { 0xeeee, 0xeeee, 0x8888, 0xdddd } },
+#if 0
+ /* These colors make it very obvious that dithering
+ * is useful even for 8-bit gradients
+ */
+ { 0x00000, { 0x6666, 0x3333, 0x3333, 0xffff } },
+ { 0x10000, { 0x3333, 0x6666, 0x6666, 0xffff } },
+#endif
+ };
+ pixman_point_fixed_t p1, p2;
+
+ enable_divbyzero_exceptions ();
+
+ dest_img = pixman_image_create_bits (PIXMAN_x8r8g8b8,
+ WIDTH, HEIGHT,
+ NULL, 0);
+
+ p1.x = p1.y = 0x0000;
+ p2.x = WIDTH << 16;
+ p2.y = HEIGHT << 16;
+
+ src_img = pixman_image_create_linear_gradient (&p1, &p2, stops,
ARRAY_LENGTH (stops));
+
+ pixman_image_composite32 (PIXMAN_OP_OVER,
+ src_img,
+ NULL,
+ dest_img,
+ 0, 0,
+ 0, 0,
+ 0, 0,
+ WIDTH, HEIGHT);
+
+ show_image (dest_img);
+
+ pixman_image_unref (dest_img);
+
+ return 0;
+}
--
1.7.4
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