SkPaintFilterCanvas should inherit the target canvas state

tests/CanvasTest.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*  Description:
  *      This test defines a series of elementatry test steps that perform
  *      a single or a small group of canvas API calls. Each test step is
@@ skipping 34 matching lines @@
  */
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkClipStack.h"
 #include "SkDeferredCanvas.h"
 #include "SkDevice.h"
 #include "SkDocument.h"
 #include "SkMatrix.h"
 #include "SkNWayCanvas.h"
 #include "SkPaint.h"
+#include "SkPaintFilterCanvas.h"
 #include "SkPath.h"
 #include "SkPicture.h"
 #include "SkPictureRecord.h"
 #include "SkPictureRecorder.h"
 #include "SkRect.h"
 #include "SkRegion.h"
 #include "SkShader.h"
 #include "SkStream.h"
 #include "SkSurface.h"
 #include "SkTDArray.h"
@@ skipping 710 matching lines @@
     canvas.restore();
     canvas.save();
     path.moveTo(5, 5);
     canvas.clipPath(path);
     canvas.restore();
     canvas.save();
     path.moveTo(7, 7);
     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);
+}