Fix recording of saveLayout with unusual Xfermodes.

tests/RecordingXfermodeTest.cpp

+/*
+ * Copyright 2014 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 "../include/core/SkCanvas.h"
+#include "../include/core/SkPicture.h"
+#include "../include/core/SkStream.h"
+#include "../include/core/SkString.h"
+#include "../include/record/SkRecording.h"
+#include "../include/core/SkPictureRecorder.h"
+#include <cstring>
+
+// Verify that replay of a recording into a clipped canvas
+// produces the correct bitmap.
+// This arose from http://crbug.com/401593 which has
+// https://code.google.com/p/skia/issues/detail?id=1291 as its root cause.
+
+
+namespace {
+
+class Drawer {
+ public:
+  virtual ~Drawer() {}
+  virtual const SkImageInfo& imageInfo() const = 0;
+  virtual void draw(SkCanvas*, const SkRect&, SkXfermode::Mode) const = 0;
+};
+
+class ExampleDrawer : public Drawer {

[mtklein, 2014/09/12 19:20:08]

Generally I'm keen on interfaces like this, but perhaps we can drop Drawer and
rename ExampleDrawer to Drawer?  There don't seem to be any others.

[dneto, 2014/09/12 20:41:42]

Done.

+ public:
+  explicit ExampleDrawer()
+      : imageInfo_(SkImageInfo::MakeN32Premul(200,100))

[mtklein, 2014/09/12 19:20:08]

Generally, Skia style wants a big "foo_ -> fFoo" and a 2-space -> 4-space find
and replace here.

[dneto, 2014/09/12 20:41:42]

Done.

+  {
+    circleBM_.allocPixels( SkImageInfo::MakeN32Premul(100,100) );
+    SkCanvas canvas(circleBM_);
+    canvas.clear(0xffffffff);
+    SkPaint circlePaint;
+    circlePaint.setColor(0xff000000);
+    canvas.drawCircle(50,50,50,circlePaint);
+  }
+
+  const SkImageInfo& imageInfo() const { return imageInfo_; }
+
+  void draw(SkCanvas* canvas, const SkRect& clipRect, SkXfermode::Mode mode) const {
+    SkPaint greenPaint;
+    greenPaint.setColor(0xff008000);
+    SkPaint blackPaint;
+    blackPaint.setColor(0xff000000);
+    SkPaint whitePaint;
+    whitePaint.setColor(0xffffffff);
+    SkPaint layerPaint;
+    layerPaint.setColor(0xff000000);
+    layerPaint.setXfermodeMode(mode);
+    SkRect canvasRect(SkRect::MakeWH(imageInfo_.width(),imageInfo_.height()));
+
+    canvas->clipRect(clipRect);
+    canvas->clear(0xff000000);
+
+    canvas->saveLayer(NULL,&blackPaint);
+      canvas->drawRect(canvasRect,greenPaint);
+      canvas->saveLayer(NULL,&layerPaint);
+        canvas->drawBitmapRect(circleBM_,SkRect::MakeXYWH(20,20,60,60),&blackPaint);
+      canvas->restore();
+    canvas->restore();
+  }
+
+ private:
+  const SkImageInfo imageInfo_;
+  SkBitmap circleBM_;
+};
+
+#if 0
+void writeToFile(std::string fname, SkPicture* picture) {
+  SkFILEWStream fs(fname.c_str());
+  picture->serialize(&fs,NULL);
+  fs.flush();
+}
+#endif
+
+class RecordingStrategy {
+ public:
+  virtual ~RecordingStrategy() {}
+  virtual void init(const SkImageInfo&) = 0;
+  virtual const SkBitmap& recordAndReplay(const Drawer& drawer,
+                                          const SkRect& intoClip,
+                                          SkXfermode::Mode) = 0;
+};
+
+class BitmapBackedCanvasStrategy : public RecordingStrategy {
+  // This version just draws into a bitmap-backed canvas.
+ public:
+  BitmapBackedCanvasStrategy() {}
+
+  virtual void init(const SkImageInfo& imageInfo) {
+    bitmap_.allocPixels(imageInfo);
+  }
+
+  virtual const SkBitmap& recordAndReplay(const Drawer& drawer,
+                                          const SkRect& intoClip,
+                                          SkXfermode::Mode mode) {
+    SkCanvas canvas(bitmap_);
+    canvas.clear(0xffffffff);
+    // Note that the scene is drawn just into the clipped region!
+    canvas.clipRect(intoClip);
+    drawer.draw(&canvas, intoClip, mode); // Shouild be canvas-wide...
+    return bitmap_;
+  }
+
+ private:
+  SkBitmap bitmap_;
+};
+
+class TiledPictureRecorderStrategy : public RecordingStrategy {
+  // This version draws the entire scene into an SkPictureRecorder,
+  // then replays through a clip rectangle.
+  // As of this writing, SkPictureRecorder is a deprecated API, but is
+  // still used in Chrome.
+  // It's also the one that proved to be buggy.
+ public:
+  TiledPictureRecorderStrategy() {}
+
+  virtual void init(const SkImageInfo& imageInfo) {
+    bitmap_.allocPixels(imageInfo);
+    width_ = imageInfo.width();
+    height_= imageInfo.height();
+  }
+
+  virtual const SkBitmap& recordAndReplay(const Drawer& drawer,
+                                          const SkRect& intoClip,
+                                          SkXfermode::Mode mode) {
+    SkTileGridFactory::TileGridInfo tileGridInfo = { {100,100}, {0,0}, {0,0} };
+    SkTileGridFactory factory(tileGridInfo);
+    SkPictureRecorder recorder;
+    SkRect canvasRect(SkRect::MakeWH(width_,height_));
+    SkCanvas* canvas = recorder.beginRecording( width_, height_, &factory);
+    drawer.draw(canvas, canvasRect, mode);
+    SkAutoTDelete<SkPicture> picture(recorder.endRecording());
+
+    SkCanvas replayCanvas(bitmap_);
+    replayCanvas.clear(0xffffffff);
+    replayCanvas.clipRect(intoClip);
+    picture->playback(&replayCanvas);
+
+    return bitmap_;
+  }
+
+ private:
+  SkBitmap bitmap_;
+  int width_;
+  int height_;
+};
+
+class SkRecordingStrategy : public RecordingStrategy {
+  // This version draws the entire scene via the SkRecording API.
+  // then replays through a clip rectangle.
+  // As of this writing, SkRecording is an experimental API.
+ public:
+  SkRecordingStrategy() {}
+
+  virtual void init(const SkImageInfo& imageInfo) {
+    bitmap_.allocPixels(imageInfo);
+    width_ = imageInfo.width();
+    height_= imageInfo.height();
+  }
+
+  virtual const SkBitmap& recordAndReplay(const Drawer& drawer,
+                                          const SkRect& intoClip,
+                                          SkXfermode::Mode mode) {
+    EXPERIMENTAL::SkRecording recording(width_, height_);
+    SkRect canvasRect(SkRect::MakeWH(width_,height_));
+    drawer.draw(recording.canvas(), canvasRect, mode);
+    SkAutoTDelete<const EXPERIMENTAL::SkPlayback> playback(recording.releasePlayback());
+
+    SkCanvas replayCanvas(bitmap_);
+    replayCanvas.clear(0xffffffff);
+    replayCanvas.clipRect(intoClip);
+    playback->draw(&replayCanvas);
+
+    return bitmap_;
+  }
+
+ private:
+  SkBitmap bitmap_;
+  int width_;
+  int height_;
+};
+
+}
+
+
+
+DEF_TEST(SkRecordingAccuracyXfermode, reporter) {
+#define FINEGRAIN 0
+
+  const ExampleDrawer drawer;
+
+  BitmapBackedCanvasStrategy golden; // This is the expected result.
+  TiledPictureRecorderStrategy tiled;
+  SkRecordingStrategy recording;
+
+  golden.init(drawer.imageInfo());
+  tiled.init(drawer.imageInfo());
+  recording.init(drawer.imageInfo());
+
+#if !FINEGRAIN
+  unsigned numErrors = 0;
+  SkString errors;
+#endif
+
+  for (int iMode = 0; iMode < int(SkXfermode::kLastMode) ; iMode++ ) {
+    const SkRect& clip = SkRect::MakeXYWH(100,0,100,100);
+    SkXfermode::Mode mode = SkXfermode::Mode(iMode);
+
+    const SkBitmap& goldenBM = golden.recordAndReplay(drawer, clip, mode);
+    const SkBitmap& tiledBM = tiled.recordAndReplay(drawer, clip, mode);
+    const SkBitmap& recordingBM = recording.recordAndReplay(drawer, clip, mode);
+
+    size_t pixelsSize = goldenBM.getSize();
+    REPORTER_ASSERT( reporter, pixelsSize == tiledBM.getSize() );
+    REPORTER_ASSERT( reporter, pixelsSize == recordingBM.getSize() );
+
+    // The pixel arrays should match.
+#if FINEGRAIN
+    REPORTER_ASSERT_MESSAGE( reporter,
+                             0==memcmp( goldenBM.getPixels(), tiledBM.getPixels(), pixelsSize ),
+                             "Tiled bitmap is wrong");
+    REPORTER_ASSERT_MESSAGE( reporter,
+                             0==memcmp( goldenBM.getPixels(), recordingBM.getPixels(), pixelsSize )
+                             "SkRecorder bitmap is wrong");
+#else
+    if ( memcmp( goldenBM.getPixels(), tiledBM.getPixels(), pixelsSize ) ) {
+      numErrors++;
+      SkString str;
+      str.printf("For SkXfermode %d %s:  Tiled recorder bitmap is wrong\n", iMode, SkXfermode::ModeName(mode));
+      errors.append(str);
+    }
+    if ( memcmp( goldenBM.getPixels(), recordingBM.getPixels(), pixelsSize ) ) {
+      numErrors++;
+      SkString str;
+      str.printf("For SkXfermode %d %s:  SkRecording bitmap is wrong\n", iMode, SkXfermode::ModeName(mode));
+      errors.append(str);
+    }
+#endif
+  }
+  REPORTER_ASSERT_MESSAGE( reporter, 0==numErrors, errors.c_str() );
+}