Add support for serializing/deserializing of SkDrawable

src/core/SkRecordedDrawable.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkLayerInfo.h"
+#include "SkMatrix.h"
+#include "SkPictureData.h"
+#include "SkPicturePlayback.h"
+#include "SkPictureRecord.h"
+#include "SkPictureRecorder.h"
+#include "SkPictureUtils.h"
+#include "SkRecordedDrawable.h"
+#include "SkRecordDraw.h"
+
+void SkRecordedDrawable::onDraw(SkCanvas* canvas) {
+    SkDrawable* const* drawables = nullptr;
+    int drawableCount = 0;
+    if (fDrawableList) {
+        drawables = fDrawableList->begin();
+        drawableCount = fDrawableList->count();
+    }
+    SkRecordDraw(*fRecord, canvas, nullptr, drawables, drawableCount, fBBH, nullptr/*callback*/);
+}
+
+SkPicture* SkRecordedDrawable::onNewPictureSnapshot() {
+    SkBigPicture::SnapshotArray* pictList = nullptr;
+    if (fDrawableList) {
+        // TODO: should we plumb-down the BBHFactory and recordFlags from our host
+        //       PictureRecorder?
+        pictList = fDrawableList->newDrawableSnapshot();
+    }
+
+    SkAutoTUnref<SkLayerInfo> saveLayerData;
+    if (fBBH && fDoSaveLayerInfo) {
+        // TODO: can we avoid work by not allocating / filling these bounds?
+        SkAutoTMalloc<SkRect> scratchBounds(fRecord->count());
+        saveLayerData.reset(new SkLayerInfo);
+
+        SkRecordComputeLayers(fBounds, *fRecord, scratchBounds, pictList, saveLayerData);
+    }
+
+    size_t subPictureBytes = 0;
+    for (int i = 0; pictList && i < pictList->count(); i++) {
+        subPictureBytes += SkPictureUtils::ApproximateBytesUsed(pictList->begin()[i]);
+    }
+    // SkBigPicture will take ownership of a ref on both fRecord and fBBH.
+    // We're not willing to give up our ownership, so we must ref them for SkPicture.
+    return new SkBigPicture(fBounds, SkRef(fRecord.get()), pictList, SkSafeRef(fBBH.get()),
+                            saveLayerData.release(), subPictureBytes);
+}
+
+void SkRecordedDrawable::flatten(SkWriteBuffer& buffer) const {
+    // Write the bounds.
+    buffer.writeRect(fBounds);
+
+    // Create an SkPictureRecord to record the draw commands.
+    SkPictInfo info;
+    SkPictureRecord pictureRecord(SkISize::Make(fBounds.width(), fBounds.height()), 0);
+
+    // If the query contains the whole picture, don't bother with the bounding box hierarchy.
+    SkRect clipBounds;
+    pictureRecord.getClipBounds(&clipBounds);
+    SkBBoxHierarchy* bbh;
+    if (clipBounds.contains(fBounds)) {
+        bbh = nullptr;
+    } else {
+        bbh = fBBH.get();
+    }
+
+    // Record the draw commands.
+    pictureRecord.beginRecording();
+    SkRecordDraw(*fRecord, &pictureRecord, nullptr, fDrawableList->begin(), fDrawableList->count(),
+                bbh, nullptr);
+    pictureRecord.endRecording();
+
+    // Flatten the recorded commands and drawables.
+    SkPictureData pictureData(pictureRecord, info, false);
+    pictureData.flatten(buffer);
+}
+
+sk_sp<SkFlattenable> SkRecordedDrawable::CreateProc(SkReadBuffer& buffer) {
+    // Read the bounds.
+    SkRect bounds;
+    buffer.readRect(&bounds);
+
+    // Unflatten into a SkPictureData.
+    SkPictInfo info;
+    info.fCullRect = bounds;
+    SkAutoTDelete<SkPictureData> pictureData(SkPictureData::CreateFromBuffer(buffer, info));
+    if (!pictureData) {
+        return nullptr;
+    }
+
+    // Create a drawable.
+    SkPicturePlayback playback(pictureData);
+    SkPictureRecorder recorder;
+    playback.draw(recorder.beginRecording(bounds), nullptr, &buffer);
+    return recorder.finishRecordingAsDrawable();
+}