Make SkBlurImageFilter capable of cropping during blur (raster path)

SkBlurImageFilter can currently only process a source image
which is larger than or equal to the destination rect. If
the source image (or crop rect) is smaller, it is padded
out to dest size with transparent black via the 6-param
version of applyCropRect().

Fixing this requires modifying all the flavours of RGBA
box_blur() to accept a src crop rect.

BUG=skia:4502, skia:4526
CQ_EXTRA_TRYBOTS=client.skia.android:Test-Android-GCC-Nexus5-CPU-NEON-Arm7-Release-Trybot;client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Committed: https://skia.googlesource.com/skia/+/1b82ceb737c73327412f2e8a91748481e1aec9e4

Review URL: https://codereview.chromium.org/1415653003

1 files changed, 23 insertions, 21 deletions

diff --git a/src/effects/SkBlurImageFilter.cpp b/src/effects/SkBlurImageFilter.cpp
index c77a444da5..3f4c852c12 100644
--- a/src/effects/SkBlurImageFilter.cpp
+++ b/src/effects/SkBlurImageFilter.cpp
@@ -82,7 +82,7 @@ bool SkBlurImageFilter::onFilterImage(Proxy* proxy,
     }
 
     SkIRect srcBounds, dstBounds;
-    if (!this->applyCropRect(ctx, proxy, src, &srcOffset, &srcBounds, &src)) {
+    if (!this->applyCropRect(ctx, src, srcOffset, &dstBounds, &srcBounds)) {
         return false;
     }
 
@@ -91,13 +91,12 @@ bool SkBlurImageFilter::onFilterImage(Proxy* proxy,
         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());
 
@@ -112,8 +111,8 @@ bool SkBlurImageFilter::onFilterImage(Proxy* proxy,
 
     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;
     }
 
@@ -124,13 +123,16 @@ bool SkBlurImageFilter::onFilterImage(Proxy* proxy,
     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();
 
     /**
@@ -152,20 +154,20 @@ bool SkBlurImageFilter::onFilterImage(Proxy* proxy,
      * 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;
 }