Fix clip expansion in SkPictureRecord::recordRestoreOffsetPlaceholder()

tests/PictureTest.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.
  */
 #include "Test.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkData.h"
+#include "SkDevice.h"
 #include "SkError.h"
 #include "SkPaint.h"
 #include "SkPicture.h"
 #include "SkRandom.h"
 #include "SkRRect.h"
 #include "SkShader.h"
 #include "SkStream.h"
 
 #include "SkPictureUtils.h"
 
@@ skipping 522 matching lines @@
         canvas->clipPath(path2, SkRegion::kXOR_Op);
         bool nonEmpty = canvas->getClipDeviceBounds(&clipBounds);
         REPORTER_ASSERT(reporter, true == nonEmpty);
         REPORTER_ASSERT(reporter, 6 == clipBounds.fLeft);
         REPORTER_ASSERT(reporter, 6 == clipBounds.fTop);
         REPORTER_ASSERT(reporter, 8 == clipBounds.fBottom);
         REPORTER_ASSERT(reporter, 8 == clipBounds.fRight);
     }
 }
 
+/**
+ * A canvas that records the number of clip commands.
+ */
+class ClipCountingCanvas : public SkCanvas {
+public:
+    explicit ClipCountingCanvas(SkDevice* device)
+        : SkCanvas(device)
+        , fClipCount(0){
+    }
+
+    virtual bool clipRect(const SkRect& r, SkRegion::Op op, bool doAA)
+        SK_OVERRIDE {
+        fClipCount += 1;
+        return this->INHERITED::clipRect(r, op, doAA);
+    }
+
+    virtual bool clipRRect(const SkRRect& rrect, SkRegion::Op op, bool doAA)
+        SK_OVERRIDE {
+        fClipCount += 1;
+        return this->INHERITED::clipRRect(rrect, op, doAA);
+    }
+
+    virtual bool clipPath(const SkPath& path, SkRegion::Op op, bool doAA)
+        SK_OVERRIDE {
+        fClipCount += 1;
+        return this->INHERITED::clipPath(path, op, doAA);
+    }
+
+    unsigned getClipCount() const { return fClipCount; }
+
+private:
+    unsigned fClipCount;
+
+    typedef SkCanvas INHERITED;
+};
+
+static void test_clip_expansion(skiatest::Reporter* reporter) {
+    SkPicture picture;
+    SkCanvas* canvas = picture.beginRecording(10, 10, 0);
+
+    canvas->clipRect(SkRect::MakeEmpty(), SkRegion::kReplace_Op);
+    // The following expanding clip should not be skipped.
+    canvas->clipRect(SkRect::MakeXYWH(4, 4, 3, 3), SkRegion::kUnion_Op);
+    // Draw something so the optimizer doesn't just fold the world.
+    SkPaint p;
+    p.setColor(SK_ColorBLUE);
+    canvas->drawPaint(p);
+
+    SkDevice testDevice(SkBitmap::kNo_Config, 10, 10);
+    ClipCountingCanvas testCanvas(&testDevice);
+    picture.draw(&testCanvas);
+
+    // Both clips should be present on playback.
+    REPORTER_ASSERT(reporter, testCanvas.getClipCount() == 2);
+}
+
 static void TestPicture(skiatest::Reporter* reporter) {
 #ifdef SK_DEBUG
     test_deleting_empty_playback();
     test_serializing_empty_picture();
 #else
     test_bad_bitmap();
 #endif
     test_peephole();
     test_gatherpixelrefs(reporter);
     test_bitmap_with_encoded_data(reporter);
     test_clone_empty(reporter);
     test_clip_bound_opt(reporter);
+    test_clip_expansion(reporter);
 }
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("Pictures", PictureTestClass, TestPicture)