Upstreaming DropShadowImageFilter into skia, from Blink

GM imagefiltersbase will need rebaselining after this change

R=senorblanco@chromium.org

Review URL: https://codereview.chromium.org/22258005

git-svn-id: http://skia.googlecode.com/svn/trunk@10583 2bbb7eff-a529-9590-31e7-b0007b416f81

4 files changed, 94 insertions, 1 deletions

diff --git a/gm/imagefiltersbase.cpp b/gm/imagefiltersbase.cpp
index 6879e796b1..ca45eafe93 100644
--- a/gm/imagefiltersbase.cpp
+++ b/gm/imagefiltersbase.cpp
@@ -13,6 +13,7 @@
 
 #include "SkBlurImageFilter.h"
 #include "SkColorFilterImageFilter.h"
+#include "SkDropShadowImageFilter.h"
 #include "SkTestImageFilters.h"
 
 class FailImageFilter : public SkImageFilter {
@@ -156,7 +157,7 @@ protected:
         return SkString("imagefiltersbase");
     }
 
-    virtual SkISize onISize() { return SkISize::Make(700, 460); }
+    virtual SkISize onISize() { return SkISize::Make(700, 500); }
 
     void draw_frame(SkCanvas* canvas, const SkRect& r) {
         SkPaint paint;
@@ -189,6 +190,7 @@ protected:
             new FailImageFilter,
             SkColorFilterImageFilter::Create(cf),
             new SkBlurImageFilter(12.0f, 0.0f),
+            new SkDropShadowImageFilter(10.0f, 5.0f, 3.0f, SK_ColorBLUE),
         };
         cf->unref();
 
diff --git a/gyp/effects.gypi b/gyp/effects.gypi
index 63857c9903..e55cbc7ab0 100644
--- a/gyp/effects.gypi
+++ b/gyp/effects.gypi
@@ -26,6 +26,7 @@
     '<(skia_src_path)/effects/SkDashPathEffect.cpp',
     '<(skia_src_path)/effects/SkDiscretePathEffect.cpp',
     '<(skia_src_path)/effects/SkDisplacementMapEffect.cpp',
+    '<(skia_src_path)/effects/SkDropShadowImageFilter.cpp',
     '<(skia_src_path)/effects/SkEmbossMask.cpp',
     '<(skia_src_path)/effects/SkEmbossMask.h',
     '<(skia_src_path)/effects/SkEmbossMask_Table.h',
@@ -89,6 +90,7 @@
     '<(skia_include_path)/effects/SkDiscretePathEffect.h',
     '<(skia_include_path)/effects/SkDisplacementMapEffect.h',
     '<(skia_include_path)/effects/SkDrawExtraPathEffect.h',
+    '<(skia_include_path)/effects/SkDropShadowImageFilter.h',
     '<(skia_include_path)/effects/SkEmbossMaskFilter.h',
     '<(skia_include_path)/effects/SkGradientShader.h',
     '<(skia_include_path)/effects/SkKernel33MaskFilter.h',
diff --git a/include/effects/SkDropShadowImageFilter.h b/include/effects/SkDropShadowImageFilter.h
new file mode 100644
index 0000000000..501df7cf7f
--- /dev/null
+++ b/include/effects/SkDropShadowImageFilter.h
@@ -0,0 +1,26 @@
+/*
+ * 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 "SkColor.h"
+#include "SkImageFilter.h"
+#include "SkScalar.h"
+
+class SK_API SkDropShadowImageFilter : public SkImageFilter {
+public:
+    SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigma, SkColor, SkImageFilter* input = NULL);
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDropShadowImageFilter)
+
+protected:
+    explicit SkDropShadowImageFilter(SkFlattenableReadBuffer&);
+    virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
+    virtual bool onFilterImage(Proxy*, const SkBitmap& source, const SkMatrix&, SkBitmap* result, SkIPoint* loc) SK_OVERRIDE;
+
+private:
+    SkScalar fDx, fDy, fSigma;
+    SkColor fColor;
+    typedef SkImageFilter INHERITED;
+};
diff --git a/src/effects/SkDropShadowImageFilter.cpp b/src/effects/SkDropShadowImageFilter.cpp
new file mode 100644
index 0000000000..ef43a30061
--- /dev/null
+++ b/src/effects/SkDropShadowImageFilter.cpp
@@ -0,0 +1,63 @@
+/*
+ * 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 "SkDropShadowImageFilter.h"
+
+#include "SkBitmap.h"
+#include "SkBlurImageFilter.h"
+#include "SkCanvas.h"
+#include "SkColorMatrixFilter.h"
+#include "SkDevice.h"
+#include "SkFlattenableBuffers.h"
+
+SkDropShadowImageFilter::SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigma, SkColor color, SkImageFilter* input)
+    : SkImageFilter(input)
+    , fDx(dx)
+    , fDy(dy)
+    , fSigma(sigma)
+    , fColor(color)
+{
+}
+
+SkDropShadowImageFilter::SkDropShadowImageFilter(SkFlattenableReadBuffer& buffer) : SkImageFilter(buffer)
+{
+    fDx = buffer.readScalar();
+    fDy = buffer.readScalar();
+    fSigma = buffer.readScalar();
+    fColor = buffer.readColor();
+}
+
+void SkDropShadowImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const
+{
+    this->INHERITED::flatten(buffer);
+    buffer.writeScalar(fDx);
+    buffer.writeScalar(fDy);
+    buffer.writeScalar(fSigma);
+    buffer.writeColor(fColor);
+}
+
+bool SkDropShadowImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source, const SkMatrix& matrix, SkBitmap* result, SkIPoint* loc)
+{
+    SkBitmap src = source;
+    if (getInput(0) && !getInput(0)->filterImage(proxy, source, matrix, &src, loc))
+        return false;
+
+    SkAutoTUnref<SkDevice> device(proxy->createDevice(src.width(), src.height()));
+    SkCanvas canvas(device.get());
+
+    SkAutoTUnref<SkImageFilter> blurFilter(new SkBlurImageFilter(fSigma, fSigma));
+    SkAutoTUnref<SkColorFilter> colorFilter(SkColorFilter::CreateModeFilter(fColor, SkXfermode::kSrcIn_Mode));
+    SkPaint paint;
+    paint.setImageFilter(blurFilter.get());
+    paint.setColorFilter(colorFilter.get());
+    paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
+    canvas.drawBitmap(src, fDx, fDy, &paint);
+    canvas.drawBitmap(src, 0, 0);
+    *result = device->accessBitmap(false);
+    return true;
+}
+