Fix textureDomain/bleed prevention in msaa

This updates Ganesh's bleed avoidance check to handle the case where the
sample location may be outside of the rect geometry but used because it
partially covers the pixel.

BUG=skia:4066

Review URL: https://codereview.chromium.org/1237623012

1 files changed, 17 insertions, 10 deletions

diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 703b7cab5c..ea2b537520 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -868,13 +868,18 @@ static bool has_aligned_samples(const SkRect& srcRect,
 
 static bool may_color_bleed(const SkRect& srcRect,
                             const SkRect& transformedRect,
-                            const SkMatrix& m) {
+                            const SkMatrix& m,
+                            bool isMSAA) {
     // Only gets called if has_aligned_samples returned false.
     // So we can assume that sampling is axis aligned but not texel aligned.
     SkASSERT(!has_aligned_samples(srcRect, transformedRect));
     SkRect innerSrcRect(srcRect), innerTransformedRect,
         outerTransformedRect(transformedRect);
-    innerSrcRect.inset(SK_ScalarHalf, SK_ScalarHalf);
+    if (isMSAA) {
+        innerSrcRect.inset(SK_Scalar1, SK_Scalar1);
+    } else {
+        innerSrcRect.inset(SK_ScalarHalf, SK_ScalarHalf);
+    }
     m.mapRect(&innerTransformedRect, innerSrcRect);
 
     // The gap between outerTransformedRect and innerTransformedRect
@@ -895,7 +900,8 @@ static bool needs_texture_domain(const SkBitmap& bitmap,
                                  const SkRect& srcRect,
                                  GrTextureParams &params,
                                  const SkMatrix& contextMatrix,
-                                 bool bicubic) {
+                                 bool bicubic,
+                                 bool isMSAA) {
     bool needsTextureDomain = false;
     GrTexture* tex = bitmap.getTexture();
     int width = tex ? tex->width() : bitmap.width();
@@ -914,7 +920,8 @@ static bool needs_texture_domain(const SkBitmap& bitmap,
                 params.setFilterMode(GrTextureParams::kNone_FilterMode);
                 needsTextureDomain = false;
             } else {
-                needsTextureDomain = may_color_bleed(srcRect, transformedRect, contextMatrix);
+                needsTextureDomain = may_color_bleed(srcRect, transformedRect,
+                                                     contextMatrix, isMSAA);
             }
         }
     }
@@ -1095,7 +1102,8 @@ void SkGpuDevice::drawBitmapCommon(const SkDraw& draw,
                                                        srcRect,
                                                        params,
                                                        viewM,
-                                                       doBicubic);
+                                                       doBicubic,
+                                                       fRenderTarget->isUnifiedMultisampled());
         this->internalDrawBitmap(bitmap,
                                  viewM,
                                  srcRect,
@@ -1176,11 +1184,10 @@ void SkGpuDevice::drawTiledBitmap(const SkBitmap& bitmap,
                 // now offset it to make it "local" to our tmp bitmap
                 tileR.offset(-offset.fX, -offset.fY);
                 GrTextureParams paramsTemp = params;
-                bool needsTextureDomain = needs_texture_domain(bitmap,
-                                                               srcRect,
-                                                               paramsTemp,
-                                                               viewM,
-                                                               bicubic);
+                bool needsTextureDomain = needs_texture_domain(
+                                                         bitmap, srcRect, paramsTemp,
+                                                         viewM, bicubic,
+                                                         fRenderTarget->isUnifiedMultisampled());
                 this->internalDrawBitmap(tmpB,
                                          viewM,
                                          tileR,