Adding a PictureResolution option to SkPictureImageFilter

src/effects/SkPictureImageFilter.cpp

Index: src/effects/SkPictureImageFilter.cpp
diff --git a/src/effects/SkPictureImageFilter.cpp b/src/effects/SkPictureImageFilter.cpp
index 5399ea7476c2b2e269d03b4047e571adf4cbbd19..e18600db6e24275b78b09fa4e4155c99cd02bc82 100644
--- a/src/effects/SkPictureImageFilter.cpp
+++ b/src/effects/SkPictureImageFilter.cpp
@@ -16,14 +16,16 @@
 SkPictureImageFilter::SkPictureImageFilter(const SkPicture* picture, uint32_t uniqueID)
     : INHERITED(0, 0, NULL, uniqueID)
     , fPicture(SkSafeRef(picture))
-    , fCropRect(picture ? picture->cullRect() : SkRect::MakeEmpty()) {
+    , fCropRect(picture ? picture->cullRect() : SkRect::MakeEmpty())
+    , fPictureResolution(kDeviceSpace_PictureResolution) {
 }
 
 SkPictureImageFilter::SkPictureImageFilter(const SkPicture* picture, const SkRect& cropRect,
-                                           uint32_t uniqueID)
+                                           uint32_t uniqueID, PictureResolution pictureResolution)
     : INHERITED(0, 0, NULL, uniqueID)
     , fPicture(SkSafeRef(picture))
-    , fCropRect(cropRect) {
+    , fCropRect(cropRect)
+    , fPictureResolution(pictureResolution) {
 }
 
 SkPictureImageFilter::~SkPictureImageFilter() {
@@ -42,7 +44,16 @@ SkFlattenable* SkPictureImageFilter::CreateProc(SkReadBuffer& buffer) {
         buffer.validate(!buffer.readBool());
     }
     buffer.readRect(&cropRect);
+    PictureResolution pictureResolution;
+    if (buffer.isVersionLT(SkReadBuffer::kPictureImageFilterResolution_Version)) {
+        pictureResolution = kDeviceSpace_PictureResolution;
+    } else {
+        pictureResolution = (PictureResolution)buffer.readInt();
+    } 
 
+    if (pictureResolution == kLocalSpace_PictureResolution) {
+        return CreateForLocalSpace(picture, cropRect);
+    }
     return Create(picture, cropRect);
 }
 
@@ -57,6 +68,7 @@ void SkPictureImageFilter::flatten(SkWriteBuffer& buffer) const {
         buffer.writeBool(false);
     }
     buffer.writeRect(fCropRect);
+    buffer.writeInt(fPictureResolution);
 }
 
 bool SkPictureImageFilter::onFilterImage(Proxy* proxy, const SkBitmap&, const Context& ctx,
@@ -83,17 +95,61 @@ bool SkPictureImageFilter::onFilterImage(Proxy* proxy, const SkBitmap&, const Co
         return false;
     }
 
+    if (kLocalSpace_PictureResolution == fPictureResolution && 
+        (ctx.ctm().getType() & ~SkMatrix::kTranslate_Mask)) {
+        drawPictureAtLocalResolution(proxy, device.get(), bounds, ctx);
+    } else {
+        drawPictureAtDeviceResolution(proxy, device.get(), bounds, ctx);
+    }
+
+    *result = device.get()->accessBitmap(false);
+    offset->fX = bounds.fLeft;
+    offset->fY = bounds.fTop;
+    return true;
+}
+
+void SkPictureImageFilter::drawPictureAtDeviceResolution(Proxy* proxy, SkBaseDevice* device,
+                                                         const SkIRect& deviceBounds,
+                                                         const Context& ctx) const {
     // Pass explicit surface props, as the simplified canvas constructor discards device properties.
     // FIXME: switch back to the public constructor (and unfriend) after
     //        https://code.google.com/p/skia/issues/detail?id=3142 is fixed.
-    SkCanvas canvas(device.get(), proxy->surfaceProps(), SkCanvas::kDefault_InitFlags);
+    SkCanvas canvas(device, proxy->surfaceProps(), SkCanvas::kDefault_InitFlags);
 
-    canvas.translate(-SkIntToScalar(bounds.fLeft), -SkIntToScalar(bounds.fTop));
+    canvas.translate(-SkIntToScalar(deviceBounds.fLeft), -SkIntToScalar(deviceBounds.fTop));
     canvas.concat(ctx.ctm());
     canvas.drawPicture(fPicture);
+}
 
-    *result = device.get()->accessBitmap(false);
-    offset->fX = bounds.fLeft;
-    offset->fY = bounds.fTop;
-    return true;
+void SkPictureImageFilter::drawPictureAtLocalResolution(Proxy* proxy, SkBaseDevice* device,
+                                                        const SkIRect& deviceBounds,
+                                                        const Context& ctx) const {
+    SkMatrix inverseCtm;
+    if (!ctx.ctm().invert(&inverseCtm))
+        return;
+    SkRect localBounds = SkRect::Make(ctx.clipBounds());
+    inverseCtm.mapRect(&localBounds);
+    if (!localBounds.intersect(fCropRect))
+        return;
+    SkIRect localIBounds = localBounds.roundOut();
+    SkAutoTUnref<SkBaseDevice> localDevice(proxy->createDevice(localIBounds.width(), localIBounds.height()));
+
+    // Pass explicit surface props, as the simplified canvas constructor discards device properties.
+    // FIXME: switch back to the public constructor (and unfriend) after
+    //        https://code.google.com/p/skia/issues/detail?id=3142 is fixed.
+    SkCanvas localCanvas(localDevice, proxy->surfaceProps(), SkCanvas::kDefault_InitFlags);
+    localCanvas.translate(-SkIntToScalar(localIBounds.fLeft), -SkIntToScalar(localIBounds.fTop));
+    localCanvas.drawPicture(fPicture);
+
+    // Pass explicit surface props, as the simplified canvas constructor discards device properties.
+    // FIXME: switch back to the public constructor (and unfriend) after
+    //        https://code.google.com/p/skia/issues/detail?id=3142 is fixed.
+    SkCanvas canvas(device, proxy->surfaceProps(), SkCanvas::kDefault_InitFlags);
+
+    canvas.translate(-SkIntToScalar(deviceBounds.fLeft), -SkIntToScalar(deviceBounds.fTop));
+    canvas.concat(ctx.ctm());
+    SkPaint paint;
+    paint.setFilterLevel(SkPaint::kLow_FilterLevel);
+    canvas.drawBitmap(localDevice.get()->accessBitmap(false), SkIntToScalar(localIBounds.fLeft), SkIntToScalar(localIBounds.fTop), &paint);
+    //canvas.drawPicture(fPicture);
 }