The new function RgbShade() (include osd.h) can be used to generate a brighter or darker version of a given color

1 files changed, 11 insertions, 1 deletions

diff --git a/osd.c b/osd.c
index 84c5a278..2edf4fae 100644
--- a/osd.c
+++ b/osd.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: osd.c 2.29 2012/05/17 13:29:19 kls Exp $
+ * $Id: osd.c 2.30 2012/06/02 10:42:23 kls Exp $
  */
 
 #include "osd.h"
@@ -40,6 +40,16 @@ tColor HsvToColor(double H, double S, double V)
      }
 }
 
+tColor RgbShade(tColor Color, double Factor)
+{
+  double f = fabs(constrain(Factor, -1.0, 1.0));
+  double w = Factor > 0 ? f * 0xFF : 0;
+  return (Color & 0xFF000000) |
+         (min(0xFF, int((1 - f) * ((Color >> 16) & 0xFF) + w + 0.5)) << 16) |
+         (min(0xFF, int((1 - f) * ((Color >>  8) & 0xFF) + w + 0.5)) <<  8) |
+         (min(0xFF, int((1 - f) * ( Color        & 0xFF) + w + 0.5))      );
+}
+
 #define USE_ALPHA_LUT
 #ifdef USE_ALPHA_LUT
 // Alpha blending with lookup table (by Reinhard Nissl <rnissl@gmx.de>)