/*
* 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_DEFINED
#define SkSurface_DEFINED
#include "SkRefCnt.h"
#include "SkImage.h"
#include "SkSurfaceProps.h"
class SkCanvas;
class SkPaint;
class GrContext;
class GrRenderTarget;
/**
* SkSurface represents the backend/results of drawing to a canvas. For raster
* drawing, the surface will be pixels, but (for example) when drawing into
* a PDF or Picture canvas, the surface stores the recorded commands.
*
* To draw into a canvas, first create the appropriate type of Surface, and
* then request the canvas from the surface.
*
* SkSurface always has non-zero dimensions. If there is a request for a new surface, and either
* of the requested dimensions are zero, then NULL will be returned.
*/
class SK_API SkSurface : public SkRefCnt {
public:
static const SkBudgeted kYes_Budgeted = SkBudgeted::kYes;
static const SkBudgeted kNo_Budgeted = SkBudgeted::kNo;
using Budgeted = SkBudgeted;
/**
* Create a new surface, using the specified pixels/rowbytes as its
* backend.
*
* If the requested surface cannot be created, or the request is not a
* supported configuration, NULL will be returned.
*/
static SkSurface* NewRasterDirect(const SkImageInfo&, void* pixels, size_t rowBytes,
const SkSurfaceProps* = NULL);
/**
* The same as NewRasterDirect, but also accepts a call-back routine, which is invoked
* when the surface is deleted, and is passed the pixel memory and the specified context.
*/
static SkSurface* NewRasterDirectReleaseProc(const SkImageInfo&, void* pixels, size_t rowBytes,
void (*releaseProc)(void* pixels, void* context),
void* context, const SkSurfaceProps* = NULL);
/**
* Return a new surface, with the memory for the pixels automatically allocated, but respecting
* the specified rowBytes. If rowBytes==0, then a default value will be chosen. If a non-zero
* rowBytes is specified, then any images snapped off of this surface (via newImageSnapshot())
* are guaranteed to have the same rowBytes.
*
* If the requested surface cannot be created, or the request is not a
* supported configuration, NULL will be returned.
*/
static SkSurface* NewRaster(const SkImageInfo&, size_t rowBytes, const SkSurfaceProps*);
/**
* Allocate a new surface, automatically computing the rowBytes.
*/
static SkSurface* NewRaster(const SkImageInfo&, const SkSurfaceProps* = NULL);
/**
* Helper version of NewRaster. It creates a SkImageInfo with the
* specified width and height, and populates the rest of info to match
* pixels in SkPMColor format.
*/
static SkSurface* NewRasterN32Premul(int width, int height, const SkSurfaceProps* props = NULL) {
return NewRaster(SkImageInfo::MakeN32Premul(width, height), props);
}
/**
* Return a new surface using the specified render target.
*/
static SkSurface* NewRenderTargetDirect(GrRenderTarget*, const SkSurfaceProps*);
static SkSurface* NewRenderTargetDirect(GrRenderTarget* target) {
return NewRenderTargetDirect(target, NULL);
}
/**
* Used to wrap a pre-existing backend 3D API texture as a SkSurface. The kRenderTarget flag
* must be set on GrBackendTextureDesc for this to succeed. Skia will not assume ownership
* of the texture and the client must ensure the texture is valid for the lifetime of the
* SkSurface.
*/
static SkSurface* NewFromBackendTexture(GrContext*, const GrBackendTextureDesc&,
const SkSurfaceProps*);
// Legacy alias
static SkSurface* NewWrappedRenderTarget(GrContext* ctx, const GrBackendTextureDesc& desc,
const SkSurfaceProps* props) {
return NewFromBackendTexture(ctx, desc, props);
}
/**
* Used to wrap a pre-existing 3D API rendering target as a SkSurface. Skia will not assume
* ownership of the render target and the client must ensure the render target is valid for the
* lifetime of the SkSurface.
*/
static SkSurface* NewFromBackendRenderTarget(GrContext*, const GrBackendRenderTargetDesc&,
const SkSurfaceProps*);
/**
* Used to wrap a pre-existing 3D API texture as a SkSurface. Skia will treat the texture as
* a rendering target only, but unlike NewFromBackendRenderTarget, Skia will manage and own
* the associated render target objects (but not the provided texture). The kRenderTarget flag
* must be set on GrBackendTextureDesc for this to succeed. Skia will not assume ownership
* of the texture and the client must ensure the texture is valid for the lifetime of the
* SkSurface.
*/
static SkSurface* NewFromBackendTextureAsRenderTarget(
GrContext*, const GrBackendTextureDesc&, const SkSurfaceProps*);
/**
* Return a new surface whose contents will be drawn to an offscreen
* render target, allocated by the surface.
*
* The GrTextureStorageAllocator will be reused if SkImage snapshots create
* additional textures.
*/
static SkSurface* NewRenderTarget(
GrContext*, SkBudgeted, const SkImageInfo&, int sampleCount,
const SkSurfaceProps* = NULL, GrTextureStorageAllocator = GrTextureStorageAllocator());
static SkSurface* NewRenderTarget(GrContext* gr, SkBudgeted b, const SkImageInfo& info) {
return NewRenderTarget(gr, b, info, 0);
}
int width() const { return fWidth; }
int height() const { return fHeight; }
/**
* Returns a unique non-zero, unique value identifying the content of this
* surface. Each time the content is changed changed, either by drawing
* into this surface, or explicitly calling notifyContentChanged()) this
* method will return a new value.
*
* If this surface is empty (i.e. has a zero-dimention), this will return
* 0.
*/
uint32_t generationID();
/**
* Modes that can be passed to notifyContentWillChange
*/
enum ContentChangeMode {
/**
* Use this mode if it is known that the upcoming content changes will
* clear or overwrite prior contents, thus making them discardable.
*/
kDiscard_ContentChangeMode,
/**
* Use this mode if prior surface contents need to be preserved or
* if in doubt.
*/
kRetain_ContentChangeMode,
};
/**
* Call this if the contents are about to change. This will (lazily) force a new
* value to be returned from generationID() when it is called next.
*
* CAN WE DEPRECATE THIS?
*/
void notifyContentWillChange(ContentChangeMode mode);
enum BackendHandleAccess {
kFlushRead_BackendHandleAccess, //!< caller may read from the backend object
kFlushWrite_BackendHandleAccess, //!< caller may write to the backend object
kDiscardWrite_BackendHandleAccess, //!< caller must over-write the entire backend object
};
/*
* These are legacy aliases which will be removed soon
*/
static const BackendHandleAccess kFlushRead_TextureHandleAccess =
kFlushRead_BackendHandleAccess;
static const BackendHandleAccess kFlushWrite_TextureHandleAccess =
kFlushWrite_BackendHandleAccess;
static const BackendHandleAccess kDiscardWrite_TextureHandleAccess =
kDiscardWrite_BackendHandleAccess;
/**
* Retrieves the backend API handle of the texture used by this surface, or 0 if the surface
* is not backed by a GPU texture.
*
* The returned texture-handle is only valid until the next draw-call into the surface,
* or the surface is deleted.
*/
GrBackendObject getTextureHandle(BackendHandleAccess);
/**
* Retrieves the backend API handle of the RenderTarget backing this surface. Callers must
* ensure this function returns 'true' or else the GrBackendObject will be invalid
*
* In OpenGL this will return the FramebufferObject ID.
*/
bool getRenderTargetHandle(GrBackendObject*, BackendHandleAccess);
/**
* Return a canvas that will draw into this surface. This will always
* return the same canvas for a given surface, and is manged/owned by the
* surface. It should not be used when its parent surface has gone out of
* scope.
*/
SkCanvas* getCanvas();
/**
* Return a new surface that is "compatible" with this one, in that it will
* efficiently be able to be drawn into this surface. Typical calling
* pattern:
*
* SkSurface* A = SkSurface::New...();
* SkCanvas* canvasA = surfaceA->newCanvas();
* ...
* SkSurface* surfaceB = surfaceA->newSurface(...);
* SkCanvas* canvasB = surfaceB->newCanvas();
* ... // draw using canvasB
* canvasA->drawSurface(surfaceB); // <--- this will always be optimal!
*/
SkSurface* newSurface(const SkImageInfo&);
/**
* Returns an image of the current state of the surface pixels up to this
* point. Subsequent changes to the surface (by drawing into its canvas)
* will not be reflected in this image. If a copy must be made the Budgeted
* parameter controls whether it counts against the resource budget
* (currently for the gpu backend only).
*/
SkImage* newImageSnapshot(SkBudgeted = SkBudgeted::kYes);
/**
* In rare instances a client may want a unique copy of the SkSurface's contents in an image
* snapshot. This enum can be used to enforce that the image snapshot's backing store is not
* shared with another image snapshot or the surface's backing store. This is generally more
* expensive. This was added for Chromium bug 585250.
*/
enum ForceUnique {
kNo_ForceUnique,
kYes_ForceUnique
};
SkImage* newImageSnapshot(SkBudgeted, ForceUnique);
/**
* Though the caller could get a snapshot image explicitly, and draw that,
* it seems that directly drawing a surface into another canvas might be
* a common pattern, and that we could possibly be more efficient, since
* we'd know that the "snapshot" need only live until we've handed it off
* to the canvas.
*/
void draw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*);
/**
* If the surface has direct access to its pixels (i.e. they are in local
* RAM) return the const-address of those pixels, and if not null, return
* the ImageInfo and rowBytes. The returned address is only valid while
* the surface object is in scope, and no API call is made on the surface
* or its canvas.
*
* On failure, returns NULL and the info and rowBytes parameters are
* ignored.
*/
const void* peekPixels(SkImageInfo* info, size_t* rowBytes);
/**
* Copy the pixels from the surface into the specified buffer (pixels + rowBytes),
* converting them into the requested format (dstInfo). The surface pixels are read
* starting at the specified (srcX,srcY) location.
*
* The specified ImageInfo and (srcX,srcY) offset specifies a source rectangle
*
* srcR.setXYWH(srcX, srcY, dstInfo.width(), dstInfo.height());
*
* srcR is intersected with the bounds of the base-layer. If this intersection is not empty,
* then we have two sets of pixels (of equal size). Replace the dst pixels with the
* corresponding src pixels, performing any colortype/alphatype transformations needed
* (in the case where the src and dst have different colortypes or alphatypes).
*
* This call can fail, returning false, for several reasons:
* - If srcR does not intersect the surface bounds.
* - If the requested colortype/alphatype cannot be converted from the surface's types.
*/
bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
int srcX, int srcY);
const SkSurfaceProps& props() const { return fProps; }
/**
* Issue any pending surface IO to the current backend 3D API and resolve any surface MSAA.
*/
void prepareForExternalIO();
protected:
SkSurface(int width, int height, const SkSurfaceProps*);
SkSurface(const SkImageInfo&, const SkSurfaceProps*);
// called by subclass if their contents have changed
void dirtyGenerationID() {
fGenerationID = 0;
}
private:
const SkSurfaceProps fProps;
const int fWidth;
const int fHeight;
uint32_t fGenerationID;
typedef SkRefCnt INHERITED;
};
#endif