ARGBToRGB565 C version use unsigned dither matrix pattern to bump pixels to next brighter value.

BUG=407
TESTED=unittest passes
R=harryjin@google.com

Review URL: https://webrtc-codereview.appspot.com/43539004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1306 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1305
+Version: 1306
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1305
+#define LIBYUV_VERSION 1306
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/row_common.cc

@@ -203,24 +203,24 @@ void ARGBToRGB565DitherRow_C(const uint8* src_argb, uint8* dst_rgb,
                              const uint8* dither8x8, int width) {
   int x;
   for (x = 0; x < width - 1; x += 2) {
-    int dither0 = dither8x8[x & 7] - 128;
-    int dither1 = dither8x8[(x & 7) + 1] - 128;
-    uint8 b0 = Clamp(src_argb[0] + dither0) >> 3;
-    uint8 g0 = Clamp(src_argb[1] + dither0) >> 2;
-    uint8 r0 = Clamp(src_argb[2] + dither0) >> 3;
-    uint8 b1 = Clamp(src_argb[4] + dither1) >> 3;
-    uint8 g1 = Clamp(src_argb[5] + dither1) >> 2;
-    uint8 r1 = Clamp(src_argb[6] + dither1) >> 3;
+    int dither0 = dither8x8[x & 7];
+    int dither1 = dither8x8[(x + 1) & 7];
+    uint8 b0 = clamp255(src_argb[0] + dither0) >> 3;
+    uint8 g0 = clamp255(src_argb[1] + dither0) >> 2;
+    uint8 r0 = clamp255(src_argb[2] + dither0) >> 3;
+    uint8 b1 = clamp255(src_argb[4] + dither1) >> 3;
+    uint8 g1 = clamp255(src_argb[5] + dither1) >> 2;
+    uint8 r1 = clamp255(src_argb[6] + dither1) >> 3;
     WRITEWORD(dst_rgb, b0 | (g0 << 5) | (r0 << 11) |
               (b1 << 16) | (g1 << 21) | (r1 << 27));
     dst_rgb += 4;
     src_argb += 8;
   }
   if (width & 1) {
-    int dither0 = dither8x8[(width - 1) & 7] - 128;
-    uint8 b0 = Clamp(src_argb[0] + dither0) >> 3;
-    uint8 g0 = Clamp(src_argb[1] + dither0) >> 2;
-    uint8 r0 = Clamp(src_argb[2] + dither0) >> 3;
+    int dither0 = dither8x8[(width - 1) & 7];
+    uint8 b0 = clamp255(src_argb[0] + dither0) >> 3;
+    uint8 g0 = clamp255(src_argb[1] + dither0) >> 2;
+    uint8 r0 = clamp255(src_argb[2] + dither0) >> 3;
     *(uint16*)(dst_rgb) = b0 | (g0 << 5) | (r0 << 11);
   }
 }