Preserve GrContext's matrix when calling SkShader::asNewEffect.

src/gpu/SkGr.cpp

Index: src/gpu/SkGr.cpp
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index 78df53e38ae7c3a3b706b21773c6b448052cbc12..6f6bf71a603582fb382740293ff578db8a1736c9 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -378,6 +378,20 @@ void SkPaint2GrPaintNoShader(GrContext* context, const SkPaint& skPaint, bool ju
     }
 }
 

[robertphillips, 2014/05/20 14:36:16]

Should this be in GrContext like the other two?

+class AutoMatrix {
+public:
+    AutoMatrix(GrContext* context) {
+        fMatrix = context->getMatrix();
+        fContext = context;
+    }
+    ~AutoMatrix() {

[robertphillips, 2014/05/20 14:36:16]

Don't we usually have a "if (NULL != fContext)" guard?

+        fContext->setMatrix(fMatrix);
+    }
+private:
+    GrContext* fContext;
+    SkMatrix fMatrix;
+};
+
 void SkPaint2GrPaintShader(GrContext* context, const SkPaint& skPaint,
                            bool constantColor, GrPaint* grPaint) {
     SkShader* shader = skPaint.getShader();
@@ -386,9 +400,12 @@ void SkPaint2GrPaintShader(GrContext* context, const SkPaint& skPaint,
         return;
     }
 
-    // SkShader::asNewEffect() may do offscreen rendering. Setup default drawing state and require
-    // the shader to set a render target.
-    GrContext::AutoWideOpenIdentityDraw awo(context, NULL);
+    // SkShader::asNewEffect() may do offscreen rendering. Save off the current RT, clip, and
+    // matrix. We don't reset the matrix on the context because SkShader::asNewEffect may use
+    // GrContext::getMatrix() to know the transformation from local coords to device space.
+    GrContext::AutoRenderTarget art(context, NULL);
+    GrContext::AutoClip ac(context, GrContext::AutoClip::kWideOpen_InitialClip);
+    AutoMatrix am(context);
 
     // setup the shader as the first color effect on the paint
     SkAutoTUnref<GrEffectRef> effect(shader->asNewEffect(context, skPaint, NULL));