nx-X11: Fix alpha premultiplication in XRenderParseColor. Fixes: #893.

Due to C arithmetic conversion rules we must use an unsigned constant
(or a cast) to perform the multiplication using unsigned arithmetic.

Fixes ArcticaProject/nx-libs#55.

Author: Emanuele Giaquinta <emanuele.giaquinta@gmail.com>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>

v2: backport to nx-libs 3.6.x (Mike Gabriel)
v3: backport to nx-libs 3.5.0.x (Mihai Moldovan)

Adds:
  - 0040_nx-X11_Fix-alpha-premultiplication-in-XRenderPa.full.patch

1 files changed, 31 insertions, 0 deletions

diff --git a/debian/patches/0040_nx-X11_Fix-alpha-premultiplication-in-XRenderPa.full.patch b/debian/patches/0040_nx-X11_Fix-alpha-premultiplication-in-XRenderPa.full.patch
new file mode 100644
index 000000000..eadfdeaa3
--- /dev/null
+++ b/debian/patches/0040_nx-X11_Fix-alpha-premultiplication-in-XRenderPa.full.patch
@@ -0,0 +1,31 @@
+commit ffc87da60b2262432d56f15332b3edd15b7e00b2
+Author: Emanuele Giaquinta <emanuele.giaquinta@gmail.com>
+Date:   Tue Jun 23 16:09:50 2015 +0200
+
+    Fix alpha premultiplication in XRenderParseColor.
+    
+     Due to C arithmetic conversion rules we must use an unsigned constant (or a
+     cast) to perform the multiplication using unsigned arithmetic.
+    
+     Fixes ArcticaProject/nx-libs#55.
+    
+     Author: Emanuele Giaquinta <emanuele.giaquinta@gmail.com>
+     Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
+     Rebased against NX: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
+
+     v3: backport to nx-libs 3.5.0.x (Mihai Moldovan)
+
+--- a/nx-X11/lib/Xrender/Color.c
++++ b/nx-X11/lib/Xrender/Color.c
+@@ -85,8 +85,8 @@ XRenderParseColor(Display *dpy, char *spec, XRenderColor *def)
+ 	def->blue = coreColor.blue;
+ 	def->alpha = 0xffff;
+     }
+-    def->red = (def->red * def->alpha) / 65535;
+-    def->green = (def->green * def->alpha) / 65535;
+-    def->blue = (def->blue * def->alpha) / 65535;
++    def->red = (def->red * def->alpha) / 0xffffU;
++    def->green = (def->green * def->alpha) / 0xffffU;
++    def->blue = (def->blue * def->alpha) / 0xffffU;
+     return 1;
+ }