Apply the CTM to filter parameters for 4 pixel-moving filters.

src/effects/SkDropShadowImageFilter.cpp

 /*
  * 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)
     : INHERITED(input)
-    , fDx(dx)
-    , fDy(dy)
-    , fSigmaX(sigma)
-    , fSigmaY(sigma)
+    , fOffset(SkVector::Make(dx, dy))
+    , fSigma(SkVector::Make(sigma, sigma))
     , fColor(color)
 {
 }
 
 SkDropShadowImageFilter::SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigmaX, SkScalar sigmaY, SkColor color, SkImageFilter* input, const CropRect* cropRect)
     : INHERITED(input, cropRect)
-    , fDx(dx)
-    , fDy(dy)
-    , fSigmaX(sigmaX)
-    , fSigmaY(sigmaY)
+    , fOffset(SkVector::Make(dx, dy))
+    , fSigma(SkVector::Make(sigmaX, sigmaY))
     , fColor(color)
 {
 }
 
 SkDropShadowImageFilter::SkDropShadowImageFilter(SkFlattenableReadBuffer& buffer)
  : INHERITED(1, buffer) {
-    fDx = buffer.readScalar();
-    fDy = buffer.readScalar();
-    fSigmaX = buffer.readScalar();
-    fSigmaY = buffer.readScalar();
+    buffer.readPoint(&fOffset);
+    buffer.readPoint(&fSigma);
     fColor = buffer.readColor();
-    buffer.validate(SkScalarIsFinite(fDx) &&
-                    SkScalarIsFinite(fDy) &&
-                    SkScalarIsFinite(fSigmaX) &&
-                    SkScalarIsFinite(fSigmaY));
+    buffer.validate(SkScalarIsFinite(fOffset.fX) &&
+                    SkScalarIsFinite(fOffset.fY) &&
+                    SkScalarIsFinite(fSigma.fX) &&
+                    SkScalarIsFinite(fSigma.fY));
 }
 
 void SkDropShadowImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const
 {
     this->INHERITED::flatten(buffer);
-    buffer.writeScalar(fDx);
-    buffer.writeScalar(fDy);
-    buffer.writeScalar(fSigmaX);
-    buffer.writeScalar(fSigmaY);
+    buffer.writePoint(fOffset);
+    buffer.writePoint(fSigma);
     buffer.writeColor(fColor);
 }
 
 bool SkDropShadowImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source, const SkMatrix& matrix, SkBitmap* result, SkIPoint* offset)
 {
     SkBitmap src = source;
     SkIPoint srcOffset = SkIPoint::Make(0, 0);
     if (getInput(0) && !getInput(0)->filterImage(proxy, source, matrix, &src, &srcOffset))
         return false;
 
     SkIRect bounds;
     src.getBounds(&bounds);
     bounds.offset(srcOffset);
     if (!this->applyCropRect(&bounds, matrix)) {
         return false;
     }
 
     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(bounds.width(), bounds.height()));
     if (NULL == device.get()) {
         return false;
     }
     SkCanvas canvas(device.get());
 
-    SkAutoTUnref<SkImageFilter> blurFilter(new SkBlurImageFilter(fSigmaX, fSigmaY));
+    SkVector sigma;
+    matrix.mapVectors(&sigma, &fSigma, 1);
+    SkAutoTUnref<SkImageFilter> blurFilter(new SkBlurImageFilter(sigma.fX, sigma.fY));
     SkAutoTUnref<SkColorFilter> colorFilter(SkColorFilter::CreateModeFilter(fColor, SkXfermode::kSrcIn_Mode));
     SkPaint paint;
     paint.setImageFilter(blurFilter.get());
     paint.setColorFilter(colorFilter.get());
     paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
+    SkVector offsetVec;
+    matrix.mapVectors(&offsetVec, &fOffset, 1);
     canvas.translate(-SkIntToScalar(bounds.fLeft), -SkIntToScalar(bounds.fTop));
-    canvas.drawBitmap(src, fDx, fDy, &paint);
+    canvas.drawBitmap(src, offsetVec.fX, offsetVec.fY, &paint);
     canvas.drawBitmap(src, 0, 0);
     *result = device->accessBitmap(false);
     offset->fX = bounds.fLeft;
     offset->fY = bounds.fTop;
     return true;
 }