commit 7a149a21c87c59c82cf484db47e88d5343af1972
author senorblanco@chromium.org <senorblanco@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Thu Dec 05 22:41:53 2013 +0000
committer senorblanco@chromium.org <senorblanco@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Thu Dec 05 22:41:53 2013 +0000
tree 0a6eeb138138422c3b2944d8a7ce2d526d0300aa
parent 902b95b055e71b5d7c3bdbf21bbcb6061ee733e1

Implement srcRect and dstRect functionality in SkBitmapSource. This is required for the "preserveAspectRatio" options of SVG's feImage. Covered by new GM "bitmapsource".

Note: I initially implemented this as a fully-generic SkResizeImageFilter, but then I realized that the dstRect should always be transformed by the filter matrix, but that the srcRect should not (since it's specified relative to the dimensions of the original bitmap). Since this would be confusing for someone attempting to use this as a generic resizing filter, I decided to build the functionality into SkBitmapSource instead.

BUG=
R=reed@google.com

Review URL: https://codereview.chromium.org/106933002

git-svn-id: http://skia.googlecode.com/svn/trunk/src@12522 2bbb7eff-a529-9590-31e7-b0007b416f81

effects/SkBitmapSource.cpp

diff --git a/effects/SkBitmapSource.cpp b/effects/SkBitmapSource.cpp
index 72f51f8..5e19744 100644
--- a/effects/SkBitmapSource.cpp
+++ b/effects/SkBitmapSource.cpp
@@ -6,24 +6,71 @@
  */
 
 #include "SkBitmapSource.h"
+#include "SkDevice.h"
+#include "SkCanvas.h"
+#include "SkFlattenableBuffers.h"
+#include "SkValidationUtils.h"
 
 SkBitmapSource::SkBitmapSource(const SkBitmap& bitmap)
   : INHERITED(0, 0),
-    fBitmap(bitmap) {
+    fBitmap(bitmap),
+    fSrcRect(SkRect::MakeWH(SkIntToScalar(bitmap.width()),
+                            SkIntToScalar(bitmap.height()))),
+    fDstRect(fSrcRect) {
+}
+
+SkBitmapSource::SkBitmapSource(const SkBitmap& bitmap, const SkRect& srcRect, const SkRect& dstRect)
+  : INHERITED(0, 0),
+    fBitmap(bitmap),
+    fSrcRect(srcRect),
+    fDstRect(dstRect) {
 }
 
 SkBitmapSource::SkBitmapSource(SkFlattenableReadBuffer& buffer)
   : INHERITED(0, buffer) {
     fBitmap.unflatten(buffer);
+    buffer.readRect(&fSrcRect);
+    buffer.readRect(&fDstRect);
+    buffer.validate(SkIsValidRect(fSrcRect) && SkIsValidRect(fDstRect));
 }
 
 void SkBitmapSource::flatten(SkFlattenableWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     fBitmap.flatten(buffer);
+    buffer.writeRect(fSrcRect);
+    buffer.writeRect(fDstRect);
 }
 
-bool SkBitmapSource::onFilterImage(Proxy*, const SkBitmap&, const SkMatrix&,
+bool SkBitmapSource::onFilterImage(Proxy* proxy, const SkBitmap&, const SkMatrix& matrix,
                                    SkBitmap* result, SkIPoint* offset) {
-    *result = fBitmap;
+    SkRect bounds, dstRect;
+    fBitmap.getBounds(&bounds);
+    matrix.mapRect(&dstRect, fDstRect);
+    if (fSrcRect == bounds && dstRect == bounds) {
+        *result = fBitmap;
+        return true;
+    }
+    SkIRect dstIRect;
+    dstRect.roundOut(&dstIRect);
+
+    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(dstIRect.width(), dstIRect.height()));
+    if (NULL == device.get()) {
+        return false;
+    }
+
+    SkCanvas canvas(device.get());
+    SkPaint paint;
+
+    // Subtract off the integer component of the translation (will be applied in loc, below).
+    dstRect.offset(-SkIntToScalar(dstIRect.fLeft), -SkIntToScalar(dstIRect.fTop));
+    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    // FIXME: this probably shouldn't be necessary, but drawBitmapRectToRect asserts
+    // None filtering when it's translate-only
+    paint.setFilterLevel(fSrcRect.width() == dstRect.width() && fSrcRect.height() == dstRect.height() ? SkPaint::kNone_FilterLevel : SkPaint::kMedium_FilterLevel);
+    canvas.drawBitmapRectToRect(fBitmap, &fSrcRect, dstRect, &paint);
+
+    *result = device.get()->accessBitmap(false);
+    offset->fX += dstIRect.fLeft;
+    offset->fY += dstIRect.fTop;
     return true;
 }