support direct writing to top layer, and hide getTopLayer()

this should remove many of the chrome callers that today call
accessBitmap on the toplayer, so they can read/write those pixels.

The ultimate fix will be to support custom allocation of raster layers
(via GDI/cairo/mac) so we can remove PlatformDevice subclassing in
skia/ext

BUG=skia:
R=bsalomon@google.com, scroggo@google.com

Review URL: https://codereview.chromium.org/197433002

git-svn-id: http://skia.googlecode.com/svn/trunk@13774 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 39 insertions, 0 deletions

diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index 098f0fc96c..8524f0b72b 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -268,6 +268,15 @@ void SkBitmapDevice::writePixels(const SkBitmap& bitmap,
 }
 #endif
 
+void* SkBitmapDevice::onAccessPixels(SkImageInfo* info, size_t* rowBytes) {
+    if (fBitmap.getPixels()) {
+        *info = fBitmap.info();
+        *rowBytes = fBitmap.rowBytes();
+        return fBitmap.getPixels();
+    }
+    return NULL;
+}
+
 static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB, size_t bytesPerRow,
                         int rowCount) {
     SkASSERT(bytesPerRow <= srcRB);
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 9fbb37bf31..4086291507 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -1040,6 +1040,15 @@ const void* SkCanvas::onPeekPixels(SkImageInfo* info, size_t* rowBytes) {
     return dev ? dev->peekPixels(info, rowBytes) : NULL;
 }
 
+void* SkCanvas::accessTopLayerPixels(SkImageInfo* info, size_t* rowBytes) {
+    return this->onAccessTopLayerPixels(info, rowBytes);
+}
+
+void* SkCanvas::onAccessTopLayerPixels(SkImageInfo* info, size_t* rowBytes) {
+    SkBaseDevice* dev = this->getTopDevice();
+    return dev ? dev->accessPixels(info, rowBytes) : NULL;
+}
+
 SkAutoROCanvasPixels::SkAutoROCanvasPixels(SkCanvas* canvas) {
     fAddr = canvas->peekPixels(&fInfo, &fRowBytes);
     if (NULL == fAddr) {
@@ -1713,6 +1722,11 @@ void SkCanvas::internal_private_getTotalClipAsPath(SkPath* path) const {
     (void)rgn.getBoundaryPath(path);
 }
 
+GrRenderTarget* SkCanvas::internal_private_accessTopLayerRenderTarget() {
+    SkBaseDevice* dev = this->getTopDevice();
+    return dev ? dev->accessRenderTarget() : NULL;
+}
+
 SkBaseDevice* SkCanvas::createLayerDevice(const SkImageInfo& info) {
     SkBaseDevice* device = this->getTopDevice();
     return device ? device->createCompatibleDeviceForSaveLayer(info) : NULL;
diff --git a/src/core/SkDevice.cpp b/src/core/SkDevice.cpp
index 666e456e8c..587181302d 100644
--- a/src/core/SkDevice.cpp
+++ b/src/core/SkDevice.cpp
@@ -194,6 +194,22 @@ bool SkBaseDevice::onReadPixels(const SkBitmap&, int x, int y, SkCanvas::Config8
     return false;
 }
 
+void* SkBaseDevice::accessPixels(SkImageInfo* info, size_t* rowBytes) {
+    SkImageInfo tmpInfo;
+    size_t tmpRowBytes;
+    if (NULL == info) {
+        info = &tmpInfo;
+    }
+    if (NULL == rowBytes) {
+        rowBytes = &tmpRowBytes;
+    }
+    return this->onAccessPixels(info, rowBytes);
+}
+
+void* SkBaseDevice::onAccessPixels(SkImageInfo* info, size_t* rowBytes) {
+    return NULL;
+}
+
 #ifdef SK_SUPPORT_LEGACY_WRITEPIXELSCONFIG
 void SkBaseDevice::writePixels(const SkBitmap&, int x, int y, SkCanvas::Config8888) {}
 #endif