add replay entry point to SkPictureRecorder for Android

tests/PictureTest.cpp

Index: tests/PictureTest.cpp
===================================================================
--- tests/PictureTest.cpp	(revision 14396)
+++ tests/PictureTest.cpp	(working copy)
@@ -774,6 +774,128 @@
     canvas->save();
 }
 
+#ifdef SK_BUILD_FOR_ANDROID
+/**
+ * A canvas that records the number of saves, saveLayers and restores.
+ */
+class SaveCountingCanvas : public SkCanvas {
+public:
+    explicit SaveCountingCanvas(int width, int height)

[mtklein, 2014/04/30 20:20:11]

I guess it's fine, but you don't need explicit here.

[robertphillips, 2014/05/27 14:10:08]

Done.

+        : INHERITED(width, height)
+        , fSaveCount(0)
+        , fSaveLayerCount(0)
+        , fRestoreCount(0){
+    }
+
+    virtual SaveLayerStrategy willSaveLayer(const SkRect* bounds, const SkPaint* paint,

[mtklein, 2014/04/30 20:20:11]

If you'd like to save space, virtual is not needed on these methods.

[robertphillips, 2014/05/27 14:10:08]

We seem to pull through the virtual keyword whenever the base class has it as
virtual.

+                                            SaveFlags flags) SK_OVERRIDE {
+        ++fSaveLayerCount;
+        return this->INHERITED::willSaveLayer(bounds, paint, flags);
+    }
+
+    virtual void willSave(SaveFlags flags) SK_OVERRIDE {
+        ++fSaveCount;
+        this->INHERITED::willSave(flags);
+    }
+
+    virtual void willRestore() SK_OVERRIDE {
+        ++fRestoreCount;
+        this->INHERITED::willRestore();
+    }
+
+    unsigned int getSaveCount() const { return fSaveCount; }

[mtklein, 2014/04/30 20:20:11]

I think we tend to just write "unsigned"

+    unsigned int getSaveLayerCount() const { return fSaveLayerCount; }
+    unsigned int getRestoreCount() const { return fRestoreCount; }
+
+private:
+    unsigned int fSaveCount;
+    unsigned int fSaveLayerCount;
+    unsigned int fRestoreCount;
+
+    typedef SkCanvas INHERITED;
+};
+
+void check_save_state(skiatest::Reporter* reporter, SkPicture* picture, 
+                      int numSaves, int numSaveLayers, int numRestores) {
+    SaveCountingCanvas canvas(picture->width(), picture->height());
+
+    picture->draw(&canvas);
+
+    REPORTER_ASSERT(reporter, numSaves == canvas.getSaveCount());
+    REPORTER_ASSERT(reporter, numSaveLayers == canvas.getSaveLayerCount());
+    REPORTER_ASSERT(reporter, numRestores == canvas.getRestoreCount());
+}
+
+class SkPictureRecorderReplayTester {
+public:
+    static SkPicture* Copy(SkPictureRecorder* recorder) {

[mtklein, 2014/04/30 20:20:11]

Can you add a note that the class is here so it can be a friend of SkPicture?

[mtklein, 2014/04/30 20:20:11]

Is Android also going to be using this for copying?  If so, we might just
present SkPicture* copyPartial() instead of replay().  We can always do the same
thing under the covers, but might give us more wiggle room?

[robertphillips, 2014/05/27 14:10:08]

Done.

[robertphillips, 2014/05/27 14:10:08]

I proposed a "snapshot" version of this in
https://codereview.chromium.org/253443003/. This CL evolved out of the
discussion of that approach. IIRC the thinking is that the replay-style
interface is more standoffish and separable.

+        SkPictureRecorder recorder2;
+
+        SkCanvas* canvas = recorder2.beginRecording(10, 10, NULL, 0);
+
+        recorder->replay(canvas);
+

[robertphillips, 2014/04/28 17:35:21]

This is where the save/saveLayer balancing occurs in the new world.

+        return recorder2.endRecording();
+    }
+};
+
+// Test out SkPictureRecorder::replay
+static void test_replay(skiatest::Reporter* reporter) {

[mtklein, 2014/04/30 20:20:11]

DEF_TEST(PictureRecorder_replay, reporter) {  ... } ?

[robertphillips, 2014/05/27 14:10:08]

Done.

+
+    // check save/saveLayer state
+    {
+        SkPictureRecorder recorder;
+
+        SkCanvas* canvas = recorder.beginRecording(10, 10, NULL, 0);
+
+        canvas->saveLayer(NULL, NULL);
+
+        SkAutoTUnref<SkPicture> copy(SkPictureRecorderReplayTester::Copy(&recorder));
+

[robertphillips, 2014/04/28 17:35:21]

The extra save and restore comes from the Copy process.

[mtklein, 2014/04/30 20:20:11]

Tack this on as a comment here?

[robertphillips, 2014/05/27 14:10:08]

Done.

+        check_save_state(reporter, copy, 2, 1, 3);
+
+        canvas->saveLayer(NULL, NULL);
+
+        SkAutoTUnref<SkPicture> final(recorder.endRecording());
+
+        check_save_state(reporter, final, 1, 2, 3);
+
+        // The copy shouldn't pick up any operations added after it was made
+        check_save_state(reporter, copy, 2, 1, 3);
+    }
+
+    // (partially) check leakage of draw ops

[mtklein, 2014/04/30 20:20:11]

Might as well split this into a separate DEF_TEST too.

[robertphillips, 2014/05/27 14:10:08]

I would prefer to keep these together since they are basically two ways of
testing the same thing. That additional operations added to the src picture
don't migrate to the copy.

+    {
+        SkPictureRecorder recorder;
+
+        SkCanvas* canvas = recorder.beginRecording(10, 10, NULL, 0);
+
+        SkRect r = SkRect::MakeWH(5, 5);
+        SkPaint p;
+
+        canvas->drawRect(r, p);
+
+        SkAutoTUnref<SkPicture> copy(SkPictureRecorderReplayTester::Copy(&recorder));
+
+        REPORTER_ASSERT(reporter, !copy->willPlayBackBitmaps());
+
+        SkBitmap bm;
+        make_bm(&bm, 10, 10, SK_ColorRED, true);
+
+        r.offset(5.0f, 5.0f);
+        canvas->drawBitmapRectToRect(bm, NULL, r);
+
+        SkAutoTUnref<SkPicture> final(recorder.endRecording());
+        REPORTER_ASSERT(reporter, final->willPlayBackBitmaps());
+
+        REPORTER_ASSERT(reporter, copy->uniqueID() != final->uniqueID());
+
+        // The snapshot shouldn't pick up any operations added after it was made
+        REPORTER_ASSERT(reporter, !copy->willPlayBackBitmaps());
+    }
+}
+#endif
+
 static void test_unbalanced_save_restores(skiatest::Reporter* reporter) {
     SkCanvas testCanvas(100, 100);
     set_canvas_to_save_count_4(&testCanvas);
@@ -1268,6 +1390,9 @@
 #else
     test_bad_bitmap();
 #endif
+#ifdef SK_BUILD_FOR_ANDROID
+    test_replay(reporter);
+#endif
     test_unbalanced_save_restores(reporter);
     test_peephole();
 #if SK_SUPPORT_GPU