X-Git-Url: https://git.dogcows.com/gitweb?a=blobdiff_plain;f=render%2Ffont.c;h=583c9f7d7af277b2986429a4036fabc38500f907;hb=263833450d3fb1ca0bfffef302c4b204a3133766;hp=5ccfb8fd2850f6267025b58f57c0a2ec69a5f0ec;hpb=f6193ad9e048c5824142d3e7feeb109f91054052;p=chaz%2Fopenbox

diff --git a/render/font.c b/render/font.c
index 5ccfb8fd..583c9f7d 100644
--- a/render/font.c
+++ b/render/font.c
@@ -285,9 +285,20 @@ void RrFontDraw(XftDraw *d, RrTextureText *t, RrRect *area)
     }
 
     if (t->shadow_offset_x || t->shadow_offset_y) {
-        c.color.red = t->shadow_color->r | t->shadow_color->r << 8;
-        c.color.green = t->shadow_color->g | t->shadow_color->g << 8;
-        c.color.blue = t->shadow_color->b | t->shadow_color->b << 8;
+        /* From nvidia's readme (chapter 23):
+
+           When rendering to a 32-bit window, keep in mind that the X RENDER
+           extension, used by most composite managers, expects "premultiplied
+           alpha" colors. This means that if your color has components (r,g,b)
+           and alpha value a, then you must render (a*r, a*g, a*b, a) into the
+           target window.
+        */
+        c.color.red = (t->shadow_color->r | t->shadow_color->r << 8) *
+            t->shadow_alpha / 255;
+        c.color.green = (t->shadow_color->g | t->shadow_color->g << 8) *
+            t->shadow_alpha / 255;
+        c.color.blue = (t->shadow_color->b | t->shadow_color->b << 8) *
+            t->shadow_alpha / 255;
         c.color.alpha = 0xffff * t->shadow_alpha / 255;
         c.pixel = t->shadow_color->pixel;