Implementation of the displacement effect (both CPU and GPU)

TEST=Added new GM called "displacement"
Review URL: https://codereview.appspot.com/7058075

git-svn-id: http://skia.googlecode.com/svn/trunk@7182 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 54 insertions, 0 deletions

diff --git a/include/effects/SkDisplacementMapEffect.h b/include/effects/SkDisplacementMapEffect.h
new file mode 100644
index 0000000000..641b4cbee4
--- /dev/null
+++ b/include/effects/SkDisplacementMapEffect.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkDisplacementMapEffect_DEFINED
+#define SkDisplacementMapEffect_DEFINED
+
+#include "SkImageFilter.h"
+#include "SkBitmap.h"
+
+class SK_API SkDisplacementMapEffect : public SkImageFilter {
+public:
+    enum ChannelSelectorType {
+        kUnknown_ChannelSelectorType,
+        kR_ChannelSelectorType,
+        kG_ChannelSelectorType,
+        kB_ChannelSelectorType,
+        kA_ChannelSelectorType,
+        kKeyBits = 3 // Max value is 4, so 3 bits are required at most
+    };
+
+    SkDisplacementMapEffect(ChannelSelectorType xChannelSelector, ChannelSelectorType yChannelSelector, SkScalar scale, SkImageFilter* displacement, SkImageFilter* color = NULL);
+
+    ~SkDisplacementMapEffect();
+
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDisplacementMapEffect)
+
+    virtual bool onFilterImage(Proxy* proxy,
+                               const SkBitmap& src,
+                               const SkMatrix& ctm,
+                               SkBitmap* dst,
+                               SkIPoint* offset) SK_OVERRIDE;
+#if SK_SUPPORT_GPU
+    virtual bool canFilterImageGPU() const SK_OVERRIDE { return true; }
+    virtual GrTexture* filterImageGPU(Proxy* proxy, GrTexture* src, const SkRect& rect) SK_OVERRIDE;
+#endif
+
+protected:
+    explicit SkDisplacementMapEffect(SkFlattenableReadBuffer& buffer);
+    virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
+
+private:
+    ChannelSelectorType fXChannelSelector;
+    ChannelSelectorType fYChannelSelector;
+    SkScalar fScale;
+    typedef SkImageFilter INHERITED;
+    SkImageFilter* getDisplacementInput() { return getInput(0); }
+    SkImageFilter* getColorInput() { return getInput(1); }
+};
+
+#endif