solid: fix premultiplication

1 files changed, 16 insertions, 6 deletions

diff --git a/pixman/pixman-solid-fill.c b/pixman/pixman-solid-fill.c
index 3d314bf..71d495c 100644
--- a/pixman/pixman-solid-fill.c
+++ b/pixman/pixman-solid-fill.c
@@ -59,10 +59,19 @@ pixman_image_create_solid_fill (pixman_color_t *color)
 {
     double components[4];
 
-    components[0] = (1. / 65535.) * color->alpha;
-    components[1] = (1. / 65535.) * color->red;
-    components[2] = (1. / 65535.) * color->green;
-    components[3] = (1. / 65535.) * color->blue;
+    if (color->alpha != 0) {
+	double inv = 1. / color->alpha;
+
+	components[0] = color->alpha / 65535.;
+	components[1] = inv * color->red;
+	components[2] = inv * color->green;
+	components[3] = inv * color->blue;
+    } else {
+	components[0] = 0;
+	components[1] = 0;
+	components[2] = 0;
+	components[3] = 0;
+    }
 
     return pixman_image_create_solid_fill_cs (&_pixman_color_space_device_rgb, components);
 }
@@ -80,8 +89,9 @@ pixman_image_create_solid_fill_cs (pixman_color_space_t        *color_space,
 
     img->type = SOLID;
 
-    for (i = 0; i < n_comp; i++)
-	img->solid.components[i] = components[i];
+    img->solid.components[0] = components[0];
+    for (i = 1; i < n_comp; i++)
+	img->solid.components[i] = components[0] * components[i];
 
     img->common.color_space = pixman_color_space_ref (color_space);
     img->common.classify = solid_fill_classify;