From: reed@android.com <reed@android.com@2bbb7eff-a529-9590-31e7-b0007b416f81>
Date: Thu, 11 Mar 2010 21:56:16 +0000 (+0000)
Subject: fix off-by-1 in alpha in colorshader setup
X-Git-Tag: submit/tizen/20180928.044319~19231
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8f073382bb6a9b3998a74e6b58654476b77b4c86;p=platform%2Fupstream%2FlibSkiaSharp.git

fix off-by-1 in alpha in colorshader setup
don't promise HasSpan16 if we're supposed to dither



git-svn-id: http://skia.googlecode.com/svn/trunk@526 2bbb7eff-a529-9590-31e7-b0007b416f81
---

diff --git a/src/core/SkShader.cpp b/src/core/SkShader.cpp
index 5290f2ff0a..f33036debc 100644
--- a/src/core/SkShader.cpp
+++ b/src/core/SkShader.cpp
@@ -256,14 +256,16 @@ bool SkColorShader::setContext(const SkBitmap& device, const SkPaint& paint,
     fColor16 = SkPack888ToRGB16(r, g, b);
 
     if (a != 255) {
-        a = SkAlpha255To256(a);
-        r = SkAlphaMul(r, a);
-        g = SkAlphaMul(g, a);
-        b = SkAlphaMul(b, a);
+        r = SkMulDiv255Round(r, a);
+        g = SkMulDiv255Round(g, a);
+        b = SkMulDiv255Round(b, a);
     }
     fPMColor = SkPackARGB32(a, r, g, b);
 
-    fFlags = kHasSpan16_Flag | kConstInY32_Flag;
+    fFlags = kConstInY32_Flag;
+    if (paint.isDither() == false) {
+        fFlags |= kHasSpan16_Flag;
+    }
     if (SkGetPackedA32(fPMColor) == 255) {
         fFlags |= kOpaqueAlpha_Flag;
     }