3 files changed, 57 insertions, 0 deletions
diff --git a/include/utils/SkPaintFilterCanvas.h b/include/utils/SkPaintFilterCanvas.h
index da0333e7e6..d693758797 100644
--- a/include/utils/SkPaintFilterCanvas.h
+++ b/include/utils/SkPaintFilterCanvas.h
@@ -16,8 +16,17 @@
 */
 class SK_API SkPaintFilterCanvas : public SkNWayCanvas {
 public:
+    /**
+     * DEPRECATED: use the variant below.
+     */
     SkPaintFilterCanvas(int width, int height);
 
+    /**
+     * The new SkPaintFilterCanvas is configured for forwarding to the
+     * specified canvas.  Also copies the target canvas matrix and clip bounds.
+     */
+    SkPaintFilterCanvas(SkCanvas* canvas);
+
     enum Type {
         kPaint_Type,
         kPoint_Type,
diff --git a/src/utils/SkPaintFilterCanvas.cpp b/src/utils/SkPaintFilterCanvas.cpp
index 0ff6ae04d1..dff1514acb 100644
--- a/src/utils/SkPaintFilterCanvas.cpp
+++ b/src/utils/SkPaintFilterCanvas.cpp
@@ -30,6 +30,18 @@ private:
 
 SkPaintFilterCanvas::SkPaintFilterCanvas(int width, int height) : INHERITED(width, height) { }
 
+SkPaintFilterCanvas::SkPaintFilterCanvas(SkCanvas *canvas)
+    : INHERITED(canvas->imageInfo().width(), canvas->imageInfo().height()) {
+
+    // Transfer matrix & clip state before adding the target canvas.
+    SkIRect devClip;
+    canvas->getClipDeviceBounds(&devClip);
+    this->clipRect(SkRect::Make(devClip));
+    this->setMatrix(canvas->getTotalMatrix());
+
+    this->addCanvas(canvas);
+}
+
 void SkPaintFilterCanvas::onDrawPaint(const SkPaint& paint) {
     AutoPaintFilter apf(this, kPaint_Type, paint);
     this->INHERITED::onDrawPaint(*apf.paint());
diff --git a/tests/CanvasTest.cpp b/tests/CanvasTest.cpp
index 0d5c862360..5aa3d46628 100644
--- a/tests/CanvasTest.cpp
+++ b/tests/CanvasTest.cpp
@@ -52,6 +52,7 @@
 #include "SkMatrix.h"
 #include "SkNWayCanvas.h"
 #include "SkPaint.h"
+#include "SkPaintFilterCanvas.h"
 #include "SkPath.h"
 #include "SkPicture.h"
 #include "SkPictureRecord.h"
@@ -782,3 +783,38 @@ DEF_TEST(Canvas_ClipEmptyPath, reporter) {
     canvas.clipPath(path);  // should not assert here
     canvas.restore();
 }
+
+namespace {
+
+class MockFilterCanvas : public SkPaintFilterCanvas {
+public:
+    MockFilterCanvas(SkCanvas* canvas) : INHERITED(canvas) { }
+
+protected:
+    void onFilterPaint(SkPaint *paint, Type type) const override { }
+
+private:
+    typedef SkPaintFilterCanvas INHERITED;
+};
+
+} // anonymous namespace
+
+// SkPaintFilterCanvas should inherit the initial target canvas state.
+DEF_TEST(PaintFilterCanvas_ConsistentState, reporter) {
+    SkCanvas canvas(100, 100);
+    canvas.clipRect(SkRect::MakeXYWH(12.7f, 12.7f, 75, 75));
+    canvas.scale(0.5f, 0.75f);
+
+    SkRect clip1, clip2;
+
+    MockFilterCanvas filterCanvas(&canvas);
+    REPORTER_ASSERT(reporter, canvas.getTotalMatrix() == filterCanvas.getTotalMatrix());
+    REPORTER_ASSERT(reporter, canvas.getClipBounds(&clip1) == filterCanvas.getClipBounds(&clip2));
+    REPORTER_ASSERT(reporter, clip1 == clip2);
+
+    filterCanvas.clipRect(SkRect::MakeXYWH(30.5f, 30.7f, 100, 100));
+    filterCanvas.scale(0.75f, 0.5f);
+    REPORTER_ASSERT(reporter, canvas.getTotalMatrix() == filterCanvas.getTotalMatrix());
+    REPORTER_ASSERT(reporter, canvas.getClipBounds(&clip1) == filterCanvas.getClipBounds(&clip2));
+    REPORTER_ASSERT(reporter, clip1 == clip2);
+}