add localmatrix-shader

src/core/SkLocalMatrixShader.cpp

Index: src/core/SkLocalMatrixShader.cpp
diff --git a/src/core/SkLocalMatrixShader.cpp b/src/core/SkLocalMatrixShader.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..63a1cedad0a284863d14d7198fa4f1489484e7f0
--- /dev/null
+++ b/src/core/SkLocalMatrixShader.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkShader.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+
+class SkLocalMatrixShader : public SkShader {
+public:
+    SkLocalMatrixShader(SkShader* proxy, const SkMatrix& localMatrix)
+        : fProxyShader(SkRef(proxy))
+        , fProxyLocalMatrix(localMatrix)
+    {}
+    
+    virtual size_t contextSize() const SK_OVERRIDE {
+        return fProxyShader->contextSize();
+    }
+    
+    virtual BitmapType asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
+                                 TileMode* mode) const SK_OVERRIDE {
+        return fProxyShader->asABitmap(bitmap, matrix, mode);
+    }
+    
+    virtual GradientType asAGradient(GradientInfo* info) const SK_OVERRIDE {
+        return fProxyShader->asAGradient(info);
+    }
+    
+    // TODO: need to augment this API to pass in a localmatrix (which we can augment)
+    virtual GrEffectRef* asNewEffect(GrContext* ctx, const SkPaint& paint) const SK_OVERRIDE {
+        return fProxyShader->asNewEffect(ctx, paint);
+    }
+    
+    virtual SkShader* refAsALocalMatrixShader(SkMatrix* localMatrix) const SK_OVERRIDE {
+        if (localMatrix) {
+            *localMatrix = fProxyLocalMatrix;
+        }
+        return SkRef(fProxyShader.get());
+    }
+    
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLocalMatrixShader)
+    
+protected:
+    SkLocalMatrixShader(SkReadBuffer&);
+    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+    virtual Context* onCreateContext(const ContextRec&, void*) const SK_OVERRIDE;
+    
+private:
+    SkAutoTUnref<SkShader> fProxyShader;
+    SkMatrix  fProxyLocalMatrix;
+    
+    typedef SkShader INHERITED;
+};
+
+SkLocalMatrixShader::SkLocalMatrixShader(SkReadBuffer& buffer) : INHERITED(buffer) {
+    buffer.readMatrix(&fProxyLocalMatrix);
+    fProxyShader.reset(buffer.readFlattenable<SkShader>());
+    if (NULL == fProxyShader.get()) {
+        sk_throw();
+    }
+}
+
+void SkLocalMatrixShader::flatten(SkWriteBuffer& buffer) const {
+    this->INHERITED::flatten(buffer);
+    buffer.writeMatrix(fProxyLocalMatrix);
+    buffer.writeFlattenable(fProxyShader.get());
+}
+
+SkShader::Context* SkLocalMatrixShader::onCreateContext(const ContextRec& rec,
+                                                        void* storage) const {
+    ContextRec newRec(rec);
+    SkMatrix tmp;
+    if (rec.fLocalMatrix) {
+        tmp.setConcat(fProxyLocalMatrix, *rec.fLocalMatrix);
+        newRec.fLocalMatrix = &tmp;
+    } else {
+        newRec.fLocalMatrix = &fProxyLocalMatrix;
+    }
+    return fProxyShader->createContext(newRec, storage);
+}
+
+#ifndef SK_IGNORE_TO_STRING
+void SkLocalMatrixShader::toString(SkString* str) const {
+    str->append("SkLocalMatrixShader: (");
+    
+    fProxyShader->toString(str);
+    
+    this->INHERITED::toString(str);
+    
+    str->append(")");
+}
+#endif
+
+SkShader* SkShader::CreateLocalMatrixShader(SkShader* proxy, const SkMatrix& localMatrix) {
+    if (localMatrix.isIdentity()) {
+        return SkRef(proxy);
+    }
+    
+    const SkMatrix* lm = &localMatrix;
+    
+    SkMatrix otherLocalMatrix;
+    SkAutoTUnref<SkShader> otherProxy(proxy->refAsALocalMatrixShader(&otherLocalMatrix));
+    if (otherProxy.get()) {
+        otherLocalMatrix.preConcat(localMatrix);
+        lm = &otherLocalMatrix;
+        proxy = otherProxy.get();
+    }
+    
+    return SkNEW_ARGS(SkLocalMatrixShader, (proxy, *lm));
+}
+