New SkRectShaderImageFilter image filter

This new changelist also introduces a new image filter called SkRectShaderImageFilter which is make to simply apply a shader on a region without using any inputs.

TEST=Added ShaderImageFilter test
Review URL: https://codereview.appspot.com/7300046

git-svn-id: http://skia.googlecode.com/svn/trunk@7808 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 74 insertions, 11 deletions

diff --git a/src/effects/SkColorFilterImageFilter.cpp b/src/effects/SkColorFilterImageFilter.cpp
index 549a6867df..b5ab255ce7 100755
--- a/src/effects/SkColorFilterImageFilter.cpp
+++ b/src/effects/SkColorFilterImageFilter.cpp
@@ -62,16 +62,17 @@ SkColorFilterImageFilter* SkColorFilterImageFilter::Create(SkColorFilter* cf,
     SkScalar colorMatrix[20], inputMatrix[20];
     SkColorFilter* inputColorFilter;
     if (input && cf->asColorMatrix(colorMatrix)
-              && (inputColorFilter = input->asColorFilter())
-              && inputColorFilter->asColorMatrix(inputMatrix)
-              && !matrix_needs_clamping(inputMatrix)) {
-        SkScalar combinedMatrix[20];
-        mult_color_matrix(inputMatrix, colorMatrix, combinedMatrix);
-        SkAutoTUnref<SkColorFilter> newCF(SkNEW_ARGS(SkColorMatrixFilter, (combinedMatrix)));
-        return SkNEW_ARGS(SkColorFilterImageFilter, (newCF, input->getInput(0)));
-    } else {
-        return SkNEW_ARGS(SkColorFilterImageFilter, (cf, input));
+              && input->asColorFilter(&inputColorFilter)
+              && (NULL != inputColorFilter)) {
+        SkAutoUnref autoUnref(inputColorFilter);
+        if (inputColorFilter->asColorMatrix(inputMatrix) && !matrix_needs_clamping(inputMatrix)) {
+            SkScalar combinedMatrix[20];
+            mult_color_matrix(inputMatrix, colorMatrix, combinedMatrix);
+            SkAutoTUnref<SkColorFilter> newCF(SkNEW_ARGS(SkColorMatrixFilter, (combinedMatrix)));
+            return SkNEW_ARGS(SkColorFilterImageFilter, (newCF, input->getInput(0)));
+        }
     }
+    return SkNEW_ARGS(SkColorFilterImageFilter, (cf, input));
 }
 
 SkColorFilterImageFilter::SkColorFilterImageFilter(SkColorFilter* cf, SkImageFilter* input) : INHERITED(input), fColorFilter(cf) {
@@ -110,6 +111,10 @@ bool SkColorFilterImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& sourc
     return true;
 }
 
-SkColorFilter* SkColorFilterImageFilter::asColorFilter() const {
-    return fColorFilter;
+bool SkColorFilterImageFilter::asColorFilter(SkColorFilter** filter) const {
+    if (filter) {
+        *filter = fColorFilter;
+        fColorFilter->ref();
+    }
+    return true;
 }
diff --git a/src/effects/SkRectShaderImageFilter.cpp b/src/effects/SkRectShaderImageFilter.cpp
new file mode 100644
index 0000000000..b6c78efd0f
--- /dev/null
+++ b/src/effects/SkRectShaderImageFilter.cpp
@@ -0,0 +1,58 @@
+/*
+ * 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 "SkRectShaderImageFilter.h"
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkDevice.h"
+#include "SkFlattenableBuffers.h"
+#include "SkShader.h"
+
+SkRectShaderImageFilter* SkRectShaderImageFilter::Create(SkShader* s, SkRect region) {
+    SkASSERT(s);
+    return SkNEW_ARGS(SkRectShaderImageFilter, (s, region));
+}
+
+SkRectShaderImageFilter::SkRectShaderImageFilter(SkShader* s, SkRect region)
+  : INHERITED(NULL)
+  , fShader(s)
+  , fRegion(region) {
+    SkASSERT(s);
+    SkSafeRef(s);
+}
+
+SkRectShaderImageFilter::SkRectShaderImageFilter(SkFlattenableReadBuffer& buffer)
+  : INHERITED(buffer) {
+    fShader = buffer.readFlattenableT<SkShader>();
+    buffer.readRect(&fRegion);
+}
+
+void SkRectShaderImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
+    this->INHERITED::flatten(buffer);
+
+    buffer.writeFlattenable(fShader);
+    buffer.writeRect(fRegion);
+}
+
+SkRectShaderImageFilter::~SkRectShaderImageFilter() {
+    SkSafeUnref(fShader);
+}
+
+bool SkRectShaderImageFilter::onFilterImage(Proxy* proxy,
+                                        const SkBitmap& source,
+                                        const SkMatrix& matrix,
+                                        SkBitmap* result,
+                                        SkIPoint* loc) {
+    SkAutoTUnref<SkDevice> device(proxy->createDevice(fRegion.width(), fRegion.height()));
+    SkCanvas canvas(device.get());
+    SkPaint paint;
+    paint.setShader(fShader);
+    canvas.drawRect(fRegion, paint);
+    *result = device.get()->accessBitmap(false);
+    return true;
+}
+