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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkSurface_Base_DEFINED
#define SkSurface_Base_DEFINED
#include "SkCanvas.h"
#include "SkImagePriv.h"
#include "SkSurface.h"
#include "SkSurfacePriv.h"
class SkSurface_Base : public SkSurface {
public:
SkSurface_Base(int width, int height, const SkSurfaceProps*);
SkSurface_Base(const SkImageInfo&, const SkSurfaceProps*);
virtual ~SkSurface_Base();
virtual GrBackendObject onGetTextureHandle(BackendHandleAccess) {
return 0;
}
virtual bool onGetRenderTargetHandle(GrBackendObject*, BackendHandleAccess) {
return false;
}
/**
* Allocate a canvas that will draw into this surface. We will cache this
* canvas, to return the same object to the caller multiple times. We
* take ownership, and will call unref() on the canvas when we go out of
* scope.
*/
virtual SkCanvas* onNewCanvas() = 0;
virtual sk_sp<SkSurface> onNewSurface(const SkImageInfo&) = 0;
/**
* Allocate an SkImage that represents the current contents of the surface.
* This needs to be able to outlive the surface itself (if need be), and
* must faithfully represent the current contents, even if the surface
* is changed after this called (e.g. it is drawn to via its canvas).
*/
virtual sk_sp<SkImage> onNewImageSnapshot() = 0;
/**
* Default implementation:
*
* image = this->newImageSnapshot();
* if (image) {
* image->draw(canvas, ...);
* image->unref();
* }
*/
virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*);
/**
* Called as a performance hint when the Surface is allowed to make it's contents
* undefined.
*/
virtual void onDiscard() {}
/**
* If the surface is about to change, we call this so that our subclass
* can optionally fork their backend (copy-on-write) in case it was
* being shared with the cachedImage.
*/
virtual void onCopyOnWrite(ContentChangeMode) = 0;
/**
* Signal the surface to remind its backing store that it's mutable again.
* Called only when we _didn't_ copy-on-write; we assume the copies start mutable.
*/
virtual void onRestoreBackingMutability() {}
/**
* Issue any pending surface IO to the current backend 3D API and resolve any surface MSAA.
*/
virtual void onPrepareForExternalIO() {}
inline SkCanvas* getCachedCanvas();
inline sk_sp<SkImage> refCachedImage();
bool hasCachedImage() const { return fCachedImage != nullptr; }
// called by SkSurface to compute a new genID
uint32_t newGenerationID();
private:
std::unique_ptr<SkCanvas> fCachedCanvas;
sk_sp<SkImage> fCachedImage;
void aboutToDraw(ContentChangeMode mode);
// Returns true if there is an outstanding image-snapshot, indicating that a call to aboutToDraw
// would trigger a copy-on-write.
bool outstandingImageSnapshot() const;
friend class SkCanvas;
friend class SkSurface;
typedef SkSurface INHERITED;
};
SkCanvas* SkSurface_Base::getCachedCanvas() {
if (nullptr == fCachedCanvas) {
fCachedCanvas = std::unique_ptr<SkCanvas>(this->onNewCanvas());
if (fCachedCanvas) {
fCachedCanvas->setSurfaceBase(this);
}
}
return fCachedCanvas.get();
}
sk_sp<SkImage> SkSurface_Base::refCachedImage() {
if (fCachedImage) {
return fCachedImage;
}
fCachedImage = this->onNewImageSnapshot();
SkASSERT(!fCachedCanvas || fCachedCanvas->getSurfaceBase() == this);
return fCachedImage;
}
#endif
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