Upstreaming DropShadowImageFilter into skia, from Blink

GM imagefiltersbase will need rebaselining after this change

R=senorblanco@chromium.org

Committed: https://code.google.com/p/skia/source/detail?r=10583

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

git-svn-id: http://skia.googlecode.com/svn/trunk/src@10626 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 65 insertions, 0 deletions

diff --git a/effects/SkDropShadowImageFilter.cpp b/effects/SkDropShadowImageFilter.cpp
new file mode 100644
index 00000000..c9cfd602
--- /dev/null
+++ b/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) : INHERITED(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;
+}
+
diff --git a/ports/SkGlobalInitialization_default.cpp b/ports/SkGlobalInitialization_default.cpp
index a85fb6d1..24edd31e 100644
--- a/ports/SkGlobalInitialization_default.cpp
+++ b/ports/SkGlobalInitialization_default.cpp
@@ -36,6 +36,7 @@
 #include "SkDataSet.h"
 #include "SkDiscretePathEffect.h"
 #include "SkDisplacementMapEffect.h"
+#include "SkDropShadowImageFilter.h"
 #include "SkEmptyShader.h"
 #include "SkEmbossMaskFilter.h"
 #include "SkFlattenable.h"
@@ -78,6 +79,7 @@ void SkFlattenable::InitializeFlattenables() {
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDilateImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDiscretePathEffect)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDisplacementMapEffect)
+    SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDropShadowImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkEmbossMaskFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkEmptyShader)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkErodeImageFilter)