Initial CL to move color / coverage off of drawstate

src/gpu/GrDistanceFieldTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDistanceFieldTextContext.h"
 #include "GrAtlas.h"
 #include "GrBitmapTextContext.h"
@@ skipping 387 matching lines @@
     kRectToRect_DistanceFieldEffectFlag : 0;
     bool useBGR = SkPixelGeometryIsBGR(fDeviceProperties.pixelGeometry());
     flags |= fUseLCDText && useBGR ? kBGR_DistanceFieldEffectFlag : 0;
     
     // see if we need to create a new effect
     if (textureUniqueID != fEffectTextureUniqueID ||
         filteredColor != fEffectColor ||
         flags != fEffectFlags) {
         if (fUseLCDText) {
             GrColor colorNoPreMul = skcolor_to_grcolor_nopremultiply(filteredColor);
-            fCachedGeometryProcessor.reset(GrDistanceFieldLCDTextureEffect::Create(fCurrTexture,
+
+            // We don't use the GrPaint's color in this case because it's been premultiplied by
+            // alpha. Instead we feed in a non-premultiplied color, and multiply its alpha by
+            // the mask texture color. The end result is that we get
+            //            mask*paintAlpha*paintColor + (1-mask*paintAlpha)*dstColor
+            int a = GrColorUnpackA(fSkPaint.getColor());
+            GrColor color = GrColorPackRGBA(a, a, a, a);
+            fCachedGeometryProcessor.reset(GrDistanceFieldLCDTextureEffect::Create(color,
+                                                                                   fCurrTexture,
                                                                                    params,
                                                                                    fGammaTexture,
                                                                                    gammaParams,
                                                                                    colorNoPreMul,
                                                                                    flags));
         } else {
             flags |= kColorAttr_DistanceFieldEffectFlag;
+            GrColor color = fSkPaint.getColor();
 #ifdef SK_GAMMA_APPLY_TO_A8
             U8CPU lum = SkColorSpaceLuminance::computeLuminance(fDeviceProperties.gamma(),
                                                                 filteredColor);
-            fCachedGeometryProcessor.reset(GrDistanceFieldTextureEffect::Create(fCurrTexture,
+            fCachedGeometryProcessor.reset(GrDistanceFieldTextureEffect::Create(color,
+                                                                                fCurrTexture,
                                                                                 params,
                                                                                 fGammaTexture,
                                                                                 gammaParams,
                                                                                 lum/255.f,
                                                                                 flags));
 #else
-            fCachedGeometryProcessor.reset(GrDistanceFieldNoGammaTextureEffect::Create(fCurrTexture,
-                                                                                params, flags));
+            fCachedGeometryProcessor.reset(GrDistanceFieldNoGammaTextureEffect::Create(color,
+                                                                                       fCurrTexture,
+                                                                                       params,
+                                                                                       flags));
 #endif
         }
         fEffectTextureUniqueID = textureUniqueID;
         fEffectColor = filteredColor;
         fEffectFlags = flags;
     }
     
 }
 
 inline bool GrDistanceFieldTextContext::uploadGlyph(GrGlyph* glyph, GrFontScaler* scaler) {
@@ skipping 230 matching lines @@
     }
 }
 
 inline void GrDistanceFieldTextContext::finish() {
     this->flush();
     fTotalVertexCount = 0;
 
     GrTextContext::finish();
 }