/* * 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 "SkSurface.h" #include "SkCanvas.h" class SkSurface_Base : public SkSurface { public: SkSurface_Base(int width, int height); virtual ~SkSurface_Base(); /** * 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 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 chaged after this calle (e.g. it is drawn to via its canvas). */ virtual 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*); /** * 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; inline SkCanvas* getCachedCanvas(); inline SkImage* getCachedImage(); // called by SkSurface to compute a new genID uint32_t newGenerationID(); private: SkCanvas* fCachedCanvas; SkImage* fCachedImage; void aboutToDraw(ContentChangeMode mode); friend class SkCanvas; friend class SkSurface; inline void installIntoCanvasForDirtyNotification(); typedef SkSurface INHERITED; }; SkCanvas* SkSurface_Base::getCachedCanvas() { if (NULL == fCachedCanvas) { fCachedCanvas = this->onNewCanvas(); this->installIntoCanvasForDirtyNotification(); } return fCachedCanvas; } SkImage* SkSurface_Base::getCachedImage() { if (NULL == fCachedImage) { fCachedImage = this->onNewImageSnapshot(); this->installIntoCanvasForDirtyNotification(); } return fCachedImage; } void SkSurface_Base::installIntoCanvasForDirtyNotification() { if (NULL != fCachedCanvas) { fCachedCanvas->setSurfaceBase(this); } } #endif