Moved SkGrTexturePixelRef to SkGrPixelRef

http://codereview.appspot.com/6344054/



git-svn-id: http://skia.googlecode.com/svn/trunk@4397 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkGrPixelRef.cpp b/src/gpu/SkGrPixelRef.cpp
new file mode 100644
index 0000000..4359da2
--- /dev/null
+++ b/src/gpu/SkGrPixelRef.cpp
@@ -0,0 +1,150 @@
+
+/*
+ * Copyright 2010 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+
+#include "SkGrPixelRef.h"
+#include "GrContext.h"
+#include "GrTexture.h"
+#include "SkGr.h"
+#include "SkRect.h"
+
+// since we call lockPixels recursively on fBitmap, we need a distinct mutex,
+// to avoid deadlock with the default one provided by SkPixelRef.
+SK_DECLARE_STATIC_MUTEX(gROLockPixelsPixelRefMutex);
+
+SkROLockPixelsPixelRef::SkROLockPixelsPixelRef() : INHERITED(&gROLockPixelsPixelRefMutex) {
+}
+
+SkROLockPixelsPixelRef::~SkROLockPixelsPixelRef() {
+}
+
+void* SkROLockPixelsPixelRef::onLockPixels(SkColorTable** ctable) {
+    if (ctable) {
+        *ctable = NULL;
+    }
+    fBitmap.reset();
+//    SkDebugf("---------- calling readpixels in support of lockpixels\n");
+    if (!this->onReadPixels(&fBitmap, NULL)) {
+        SkDebugf("SkROLockPixelsPixelRef::onLockPixels failed!\n");
+        return NULL;
+    }
+    fBitmap.lockPixels();
+    return fBitmap.getPixels();
+}
+
+void SkROLockPixelsPixelRef::onUnlockPixels() {
+    fBitmap.unlockPixels();
+}
+
+bool SkROLockPixelsPixelRef::onLockPixelsAreWritable() const {
+    return false;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture,
+                                           SkBitmap::Config dstConfig) {
+    if (NULL == texture) {
+        return NULL;
+    }
+    GrContext* context = texture->getContext();
+    if (NULL == context) {
+        return NULL;
+    }
+    GrTextureDesc desc;
+
+    desc.fWidth  = texture->width();
+    desc.fHeight = texture->height();
+    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
+    desc.fConfig = SkGr::BitmapConfig2PixelConfig(dstConfig);
+
+    GrTexture* dst = context->createUncachedTexture(desc, NULL, 0);
+    if (NULL == dst) {
+        return NULL;
+    }
+
+    context->copyTexture(texture, dst->asRenderTarget());
+
+    // The render texture we have created (to perform the copy) isn't fully
+    // functional (since it doesn't have a stencil buffer). Release it here
+    // so the caller doesn't try to render to it.
+    // TODO: we can undo this release when dynamic stencil buffer attach/
+    // detach has been implemented
+    dst->releaseRenderTarget();
+
+    SkGrPixelRef* pixelRef = new SkGrPixelRef(dst);
+    GrSafeUnref(dst);
+    return pixelRef;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkGrPixelRef::SkGrPixelRef(GrSurface* surface) {
+    // The GrTexture has a ref to the GrRenderTarget but not vice versa.
+    // If the GrTexture exists take a ref to that (rather than the render
+    // target)
+    fSurface = surface->asTexture();
+    if (NULL == fSurface) {
+        fSurface = surface;
+    }
+
+    GrSafeRef(surface);
+}
+
+SkGrPixelRef::~SkGrPixelRef() {
+    GrSafeUnref(fSurface);
+}
+
+SkGpuTexture* SkGrPixelRef::getTexture() {
+    if (NULL != fSurface) {
+        return (SkGpuTexture*) fSurface->asTexture();
+    }
+    return NULL;
+}
+
+SkPixelRef* SkGrPixelRef::deepCopy(SkBitmap::Config dstConfig) {
+    if (NULL == fSurface) {
+        return NULL;
+    }
+
+    // Note that when copying a render-target-backed pixel ref, we
+    // return a texture-backed pixel ref instead.  This is because
+    // render-target pixel refs are usually created in conjunction with
+    // a GrTexture owned elsewhere (e.g., SkGpuDevice), and cannot live
+    // independently of that texture.  Texture-backed pixel refs, on the other
+    // hand, own their GrTextures, and are thus self-contained.
+    return copyToTexturePixelRef(fSurface->asTexture(), dstConfig);
+}
+
+bool SkGrPixelRef::onReadPixels(SkBitmap* dst, const SkIRect* subset) {
+    if (NULL == fSurface || !fSurface->isValid()) {
+        return false;
+    }
+
+    int left, top, width, height;
+    if (NULL != subset) {
+        left = subset->fLeft;
+        width = subset->width();
+        top = subset->fTop;
+        height = subset->height();
+    } else {
+        left = 0;
+        width = fSurface->width();
+        top = 0;
+        height = fSurface->height();
+    }
+    dst->setConfig(SkBitmap::kARGB_8888_Config, width, height);
+    dst->allocPixels();
+    SkAutoLockPixels al(*dst);
+    void* buffer = dst->getPixels();
+    return fSurface->readPixels(left, top, width, height,
+                                kSkia8888_PM_GrPixelConfig,
+                                buffer, dst->rowBytes());
+}
+