Make SkBlurImageFilter capable of cropping during blur

src/effects/SkBlurImageFilter.cpp

 /*
  * Copyright 2011 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBlurImageFilter.h"
 #include "SkColorPriv.h"
@@ skipping 64 matching lines @@
     SkIPoint srcOffset = SkIPoint::Make(0, 0);
     if (!this->filterInput(0, proxy, source, ctx, &src, &srcOffset)) {
         return false;
     }
 
     if (src.colorType() != kN32_SkColorType) {
         return false;
     }
 
     SkIRect srcBounds, dstBounds;
-    if (!this->applyCropRect(ctx, proxy, src, &srcOffset, &srcBounds, &src)) {
+    if (!this->applyCropRect(ctx, src, srcOffset, &dstBounds, &srcBounds)) {
         return false;
     }
 
     SkAutoLockPixels alp(src);
     if (!src.getPixels()) {
         return false;
     }
 
-    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(srcBounds.width(), srcBounds.height()));
+    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(dstBounds.width(), dstBounds.height()));
     if (!device) {
         return false;
     }
     *dst = device->accessBitmap(false);
     SkAutoLockPixels alp_dst(*dst);
-    dst->getBounds(&dstBounds);
 
     SkVector sigma = mapSigma(fSigma, ctx.ctm());
 
     int kernelSizeX, kernelSizeX3, lowOffsetX, highOffsetX;
     int kernelSizeY, kernelSizeY3, lowOffsetY, highOffsetY;
     getBox3Params(sigma.x(), &kernelSizeX, &kernelSizeX3, &lowOffsetX, &highOffsetX);
     getBox3Params(sigma.y(), &kernelSizeY, &kernelSizeY3, &lowOffsetY, &highOffsetY);
 
     if (kernelSizeX < 0 || kernelSizeY < 0) {
         return false;
     }
 
     if (kernelSizeX == 0 && kernelSizeY == 0) {
         src.copyTo(dst, dst->colorType());
-        offset->fX = srcBounds.fLeft;
-        offset->fY = srcBounds.fTop;
+        offset->fX = dstBounds.x() + srcOffset.x();
+        offset->fY = dstBounds.y() + srcOffset.y();
         return true;
     }
 
     SkAutoTUnref<SkBaseDevice> tempDevice(proxy->createDevice(dst->width(), dst->height()));
     if (!tempDevice) {
         return false;
     }
     SkBitmap temp = tempDevice->accessBitmap(false);
     SkAutoLockPixels alpTemp(temp);
 
-    offset->fX = srcBounds.fLeft;
-    offset->fY = srcBounds.fTop;
-    srcBounds.offset(-srcOffset);
-    const SkPMColor* s = src.getAddr32(srcBounds.left(), srcBounds.top());
+    offset->fX = dstBounds.fLeft;
+    offset->fY = dstBounds.fTop;
     SkPMColor* t = temp.getAddr32(0, 0);
     SkPMColor* d = dst->getAddr32(0, 0);
     int w = dstBounds.width(), h = dstBounds.height();
+    const SkPMColor* s = src.getAddr32(srcBounds.x() - srcOffset.x(), srcBounds.y() - srcOffset.y());
+    srcBounds.offset(-dstBounds.x(), -dstBounds.y());
+    dstBounds.offset(-dstBounds.x(), -dstBounds.y());
+    SkIRect srcBoundsT = SkIRect::MakeLTRB(srcBounds.top(), srcBounds.left(), srcBounds.bottom(), srcBounds.right());
+    SkIRect dstBoundsT = SkIRect::MakeWH(dstBounds.height(), dstBounds.width());
     int sw = src.rowBytesAsPixels();
 
     /**
      *
      * In order to make memory accesses cache-friendly, we reorder the passes to
      * use contiguous memory reads wherever possible.
      *
      * For example, the 6 passes of the X-and-Y blur case are rewritten as
      * follows. Instead of 3 passes in X and 3 passes in Y, we perform
      * 2 passes in X, 1 pass in X transposed to Y on write, 2 passes in X,
      * then 1 pass in X transposed to Y on write.
      *
      * +----+       +----+       +----+        +---+       +---+       +---+        +----+
      * + AB + ----> | AB | ----> | AB | -----> | A | ----> | A | ----> | A | -----> | AB |
      * +----+ blurX +----+ blurX +----+ blurXY | B | blurX | B | blurX | B | blurXY +----+
      *                                         +---+       +---+       +---+
      *
      * In this way, two of the y-blurs become x-blurs applied to transposed
      * images, and all memory reads are contiguous.
      */
     if (kernelSizeX > 0 && kernelSizeY > 0) {
-        SkOpts::box_blur_xx(s, sw,  t, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
-        SkOpts::box_blur_xx(t,  w,  d, kernelSizeX,  highOffsetX, lowOffsetX,  w, h);
-        SkOpts::box_blur_xy(d,  w,  t, kernelSizeX3, highOffsetX, highOffsetX, w, h);
-        SkOpts::box_blur_xx(t,  h,  d, kernelSizeY,  lowOffsetY,  highOffsetY, h, w);
-        SkOpts::box_blur_xx(d,  h,  t, kernelSizeY,  highOffsetY, lowOffsetY,  h, w);
-        SkOpts::box_blur_xy(t,  h,  d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
+        SkOpts::box_blur_xx(s, sw,  srcBounds,  t, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
+        SkOpts::box_blur_xx(t,  w,  dstBounds,  d, kernelSizeX,  highOffsetX, lowOffsetX,  w, h);
+        SkOpts::box_blur_xy(d,  w,  dstBounds,  t, kernelSizeX3, highOffsetX, highOffsetX, w, h);
+        SkOpts::box_blur_xx(t,  h,  dstBoundsT, d, kernelSizeY,  lowOffsetY,  highOffsetY, h, w);
+        SkOpts::box_blur_xx(d,  h,  dstBoundsT, t, kernelSizeY,  highOffsetY, lowOffsetY,  h, w);
+        SkOpts::box_blur_xy(t,  h,  dstBoundsT, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
     } else if (kernelSizeX > 0) {
-        SkOpts::box_blur_xx(s, sw,  d, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
-        SkOpts::box_blur_xx(d,  w,  t, kernelSizeX,  highOffsetX, lowOffsetX,  w, h);
-        SkOpts::box_blur_xx(t,  w,  d, kernelSizeX3, highOffsetX, highOffsetX, w, h);
+        SkOpts::box_blur_xx(s, sw,  srcBounds,  d, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
+        SkOpts::box_blur_xx(d,  w,  dstBounds,  t, kernelSizeX,  highOffsetX, lowOffsetX,  w, h);
+        SkOpts::box_blur_xx(t,  w,  dstBounds,  d, kernelSizeX3, highOffsetX, highOffsetX, w, h);
     } else if (kernelSizeY > 0) {
-        SkOpts::box_blur_yx(s, sw,  d, kernelSizeY,  lowOffsetY,  highOffsetY, h, w);
-        SkOpts::box_blur_xx(d,  h,  t, kernelSizeY,  highOffsetY, lowOffsetY,  h, w);
-        SkOpts::box_blur_xy(t,  h,  d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
+        SkOpts::box_blur_yx(s, sw,  srcBoundsT, d, kernelSizeY,  lowOffsetY,  highOffsetY, h, w);
+        SkOpts::box_blur_xx(d,  h,  dstBoundsT, t, kernelSizeY,  highOffsetY, lowOffsetY,  h, w);
+        SkOpts::box_blur_xy(t,  h,  dstBoundsT, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
     }
     return true;
 }
 
 
 void SkBlurImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
     if (this->getInput(0)) {
         this->getInput(0)->computeFastBounds(src, dst);
     } else {
         *dst = src;
@@ skipping 58 matching lines @@
     str->appendf("SkBlurImageFilter: (");
     str->appendf("sigma: (%f, %f) input (", fSigma.fWidth, fSigma.fHeight);
 
     if (this->getInput(0)) {
         this->getInput(0)->toString(str);
     }
 
     str->append("))");
 }
 #endif