Implement SkBaseDevice snapshot support

src/core/SkBitmapDevice.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkConfig8888.h"
 #include "SkDeviceProperties.h"
 #include "SkDraw.h"
+#include "SkImagePriv.h"
 #include "SkImage_Base.h"
 #include "SkRasterClip.h"
 #include "SkShader.h"
 #include "SkSurface.h"
 
 #define CHECK_FOR_ANNOTATION(paint) \
     do { if (paint.getAnnotation()) { return; } } while (0)
 
 static bool valid_for_bitmap_device(const SkImageInfo& info,
                                     SkAlphaType* newAlphaType) {
@@ skipping 41 matching lines @@
     SkASSERT(valid_for_bitmap_device(bitmap.info(), NULL));
 }
 
 SkBitmapDevice::SkBitmapDevice(const SkBitmap& bitmap, const SkDeviceProperties& deviceProperties)
     : SkBaseDevice(deviceProperties)
     , fBitmap(bitmap)
 {
     SkASSERT(valid_for_bitmap_device(bitmap.info(), NULL));
 }
 
+SkBitmapDevice::~SkBitmapDevice() {
+}
+
 SkBitmapDevice* SkBitmapDevice::Create(const SkImageInfo& origInfo,
                                        const SkDeviceProperties* props) {
     SkAlphaType newAT = origInfo.alphaType();
     if (!valid_for_bitmap_device(origInfo, &newAT)) {
         return NULL;
     }
 
     const SkImageInfo info = origInfo.makeAlphaType(newAT);
     SkBitmap bitmap;
 
@@ skipping 14 matching lines @@
         return SkNEW_ARGS(SkBitmapDevice, (bitmap, *props));
     } else {
         return SkNEW_ARGS(SkBitmapDevice, (bitmap));
     }
 }
 
 SkImageInfo SkBitmapDevice::imageInfo() const {
     return fBitmap.info();
 }
 
-void SkBitmapDevice::replaceBitmapBackendForRasterSurface(const SkBitmap& bm) {
-    SkASSERT(bm.width() == fBitmap.width());
-    SkASSERT(bm.height() == fBitmap.height());
-    fBitmap = bm;   // intent is to use bm's pixelRef (and rowbytes/config)
-    fBitmap.lockPixels();
+void SkBitmapDevice::deepCopyBackendIfNeeded() {
+    if (NULL != fSnapshot) {
+        if (!fSnapshot->unique()) {
+            SkBitmap prev(fBitmap);
+            prev.deepCopyTo(&fBitmap);
+            fBitmap.lockPixels();
+        }
+        fSnapshot.reset(NULL);
+    }
 }
 
 SkBaseDevice* SkBitmapDevice::onCreateDevice(const CreateInfo& cinfo, const SkPaint*) {
     SkDeviceProperties leaky(cinfo.fPixelGeometry);
     return SkBitmapDevice::Create(cinfo.fInfo, &leaky);
 }
 
 void SkBitmapDevice::lockPixels() {
     if (fBitmap.lockPixelsAreWritable()) {
         fBitmap.lockPixels();
     }
 }
 
 void SkBitmapDevice::unlockPixels() {
     if (fBitmap.lockPixelsAreWritable()) {
         fBitmap.unlockPixels();
     }
 }
 
 const SkBitmap& SkBitmapDevice::onAccessBitmap() {
+    this->deepCopyBackendIfNeeded();
     return fBitmap;
 }
 
 void* SkBitmapDevice::onAccessPixels(SkImageInfo* info, size_t* rowBytes) {
     if (fBitmap.getPixels()) {
+        this->deepCopyBackendIfNeeded();
         *info = fBitmap.info();
         *rowBytes = fBitmap.rowBytes();
         return fBitmap.getPixels();
     }
     return NULL;
 }
 
 #include "SkConfig8888.h"
 #include "SkPixelRef.h"
 
@@ skipping 197 matching lines @@
                                   const SkPoint verts[], const SkPoint textures[],
                                   const SkColor colors[], SkXfermode* xmode,
                                   const uint16_t indices[], int indexCount,
                                   const SkPaint& paint) {
     draw.drawVertices(vmode, vertexCount, verts, textures, colors, xmode,
                       indices, indexCount, paint);
 }
 
 void SkBitmapDevice::drawDevice(const SkDraw& draw, SkBaseDevice* device,
                                 int x, int y, const SkPaint& paint) {
-    const SkBitmap& src = device->accessBitmap(false);
+    SkAutoTUnref<SkImage> image(device->newImageSnapshot());
+    if (NULL == image) {
+        return;
+    }
+    SkBitmap src;
+    if (!as_IB(image.get())->getROPixels(&src)) {
+        return;
+    }
     draw.drawSprite(src, x, y, paint);
 }
 
 SkSurface* SkBitmapDevice::newSurface(const SkImageInfo& info, const SkSurfaceProps& props) {
     return SkSurface::NewRaster(info, &props);
 }
 
+void SkBitmapDevice::discard() {
+    if (NULL != fSnapshot) {
+        if (!fSnapshot->unique()) {
+            fBitmap.setPixelRef(NULL);
+            fBitmap.allocPixels();
+        }
+        fSnapshot.reset(NULL);
+    }
+}
+
+SkImage* SkBitmapDevice::newImageSnapshot() {
+    if (NULL == fSnapshot) {
+        fSnapshot.reset(this->onNewImageSnapshot());
+    }
+    return SkSafeRef(fSnapshot.get());
+}
+
+SkImage* SkBitmapDevice::onNewImageSnapshot() {
+    return SkNewImageFromBitmap(fBitmap, NULL);
+}
+
 const void* SkBitmapDevice::peekPixels(SkImageInfo* info, size_t* rowBytes) {
     const SkImageInfo bmInfo = fBitmap.info();
     if (fBitmap.getPixels() && (kUnknown_SkColorType != bmInfo.colorType())) {
         if (info) {
             *info = bmInfo;
         }
         if (rowBytes) {
             *rowBytes = fBitmap.rowBytes();
         }
         return fBitmap.getPixels();
@@ skipping 14 matching lines @@
         paint.getRasterizer() ||
         paint.getPathEffect() ||
         paint.isFakeBoldText() ||
         paint.getStyle() != SkPaint::kFill_Style ||
         !SkXfermode::IsMode(paint.getXfermode(), SkXfermode::kSrcOver_Mode))
     {
         return true;
     }
     return false;
 }