fix bug where we wrote uninitialized data to the flatten stream for shaders.

Both shader and gradient_shader write matrices to the flatten stream. However, they were
just calling write(&matrix, sizeof(SkMatrix)) and the matrix can contain lazily-computed
function ptrs as part of its internal cache. Thus two matrices that are logically the
same may write different bytes.

This is a problem because picture relies on flattening objects and then using the
flatten stream as a key into its cache. This matrix-write bug effectively kills the
effectiveness of the cache for shaders.

The fix is to write proper read/write functions for matrix (and region btw). These
call through to the existing low-level flatten routines (which just write into a
memory ptr).



git-svn-id: http://skia.googlecode.com/svn/trunk@1290 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 2 insertions, 2 deletions

diff --git a/src/effects/SkGradientShader.cpp b/src/effects/SkGradientShader.cpp
index 4eeeb68704..cfe444edd2 100644
--- a/src/effects/SkGradientShader.cpp
+++ b/src/effects/SkGradientShader.cpp
@@ -342,7 +342,7 @@ Gradient_Shader::Gradient_Shader(SkFlattenableReadBuffer& buffer) :
             recs[i].fScale = buffer.readU32();
         }
     }
-    buffer.read(&fPtsToUnit, sizeof(SkMatrix));
+    SkReadMatrix(&buffer, &fPtsToUnit);
     fFlags = 0;
 }
 
@@ -370,7 +370,7 @@ void Gradient_Shader::flatten(SkFlattenableWriteBuffer& buffer) {
             buffer.write32(recs[i].fScale);
         }
     }
-    buffer.writeMul4(&fPtsToUnit, sizeof(SkMatrix));
+    SkWriteMatrix(&buffer, fPtsToUnit);
 }
 
 bool Gradient_Shader::setContext(const SkBitmap& device,