#Topic Surface #Alias Surface_Reference ## #Class SkSurface SkSurface is responsible for managing the pixels that a canvas draws into. The pixels can be allocated either in CPU memory (a raster surface) or on the GPU (a GrRenderTarget surface). SkSurface takes care of allocating a SkCanvas that will draw into the surface. Call surface->getCanvas() to use that canvas (but don't delete it, it is owned by 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 nullptr will be returned. #Subtopic Overview #Populate ## #Subtopic Constant #Populate ## #Subtopic Related_Function #Populate ## #Subtopic Member_Function #Populate ## # ------------------------------------------------------------------------------ #Subtopic Constructor #Populate ## #Method static sk_sp MakeRasterDirect(const SkImageInfo& imageInfo, void* pixels, size_t rowBytes, const SkSurfaceProps* surfaceProps = nullptr) #In Constructor #Line # creates Surface from SkImageInfo and Pixel_Storage ## Allocates raster Surface. Canvas returned by Surface draws directly into pixels. Surface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains Color_Type and Alpha_Type supported by Raster_Surface; pixels is not nullptr; rowBytes is large enough to contain info width pixels of Color_Type. Pixel buffer size should be info height times computed rowBytes. Pixels are not initialized. To access pixels after drawing, call flush() or peekPixels. #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Raster_Surface; width and height must be greater than zero ## #Param pixels pointer to destination pixels buffer ## #Param rowBytes interval from one Surface row to the next ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example void draw(SkCanvas* ) { SkImageInfo info = SkImageInfo::MakeN32Premul(3, 3); const size_t size = info.computeMinByteSize(); SkAutoTMalloc storage(size); SkPMColor* pixels = storage.get(); sk_sp surface(SkSurface::MakeRasterDirect(info, pixels, info.minRowBytes())); SkCanvas* canvas = surface->getCanvas(); canvas->clear(SK_ColorWHITE); SkPMColor pmWhite = pixels[0]; SkPaint paint; canvas->drawPoint(1, 1, paint); canvas->flush(); // ensure that point was drawn for (int y = 0; y < info.height(); ++y) { for (int x = 0; x < info.width(); ++x) { SkDebugf("%c", *pixels++ == pmWhite ? '-' : 'x'); } SkDebugf("\n"); } } #StdOut --- -x- --- ## ## #SeeAlso MakeRasterDirectReleaseProc MakeRaster MakeRasterN32Premul SkCanvas::MakeRasterDirect #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRasterDirectReleaseProc(const SkImageInfo& imageInfo, void* pixels, size_t rowBytes, void (*releaseProc)(void* pixels, void* context), void* context, const SkSurfaceProps* surfaceProps = nullptr) #In Constructor #Line # creates Surface from SkImageInfo and Pixel_Storage ## Allocates raster Surface. Canvas returned by Surface draws directly into pixels. releaseProc is called with pixels and context when Surface is deleted. Surface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains Color_Type and Alpha_Type supported by Raster_Surface; pixels is not nullptr; rowBytes is large enough to contain info width pixels of Color_Type. Pixel buffer size should be info height times computed rowBytes. Pixels are not initialized. To access pixels after drawing, call flush() or peekPixels. #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Raster_Surface; width and height must be greater than zero ## #Param pixels pointer to destination pixels buffer ## #Param rowBytes interval from one Surface row to the next ## #Param releaseProc called when Surface is deleted; may be nullptr ## #Param context passed to releaseProc; may be nullptr ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example #Function static void release_direct_surface_storage(void* pixels, void* context) { if (pixels == context) { SkDebugf("expected release context\n"); } sk_free(pixels); } ## void draw(SkCanvas* ) { SkImageInfo info = SkImageInfo::MakeN32Premul(3, 3); const size_t rowBytes = info.minRowBytes(); void* pixels = sk_malloc_throw(info.computeByteSize(rowBytes)); sk_sp surface(SkSurface::MakeRasterDirectReleaseProc(info, pixels, rowBytes, release_direct_surface_storage, pixels)); SkCanvas* canvas = surface->getCanvas(); canvas->clear(SK_ColorWHITE); SkPMColor* colorPtr = (SkPMColor*) pixels; SkPMColor pmWhite = colorPtr[0]; SkPaint paint; canvas->drawPoint(1, 1, paint); canvas->flush(); // ensure that point was drawn for (int y = 0; y < info.height(); ++y) { for (int x = 0; x < info.width(); ++x) { SkDebugf("%c", *colorPtr++ == pmWhite ? '-' : 'x'); } SkDebugf("\n"); } } #StdOut --- -x- --- expected release context ## ## #SeeAlso MakeRasterDirect MakeRasterN32Premul MakeRaster #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRaster(const SkImageInfo& imageInfo, size_t rowBytes, const SkSurfaceProps* surfaceProps) #In Constructor #Line # creates Surface from SkImageInfo ## Allocates raster Surface. Canvas returned by Surface draws directly into pixels. Allocates and zeroes pixel memory. Pixel memory size is imageInfo.height() times rowBytes, or times imageInfo.minRowBytes() if rowBytes is zero. Pixel memory is deleted when Surface is deleted. Surface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains Color_Type and Alpha_Type supported by Raster_Surface; rowBytes is large enough to contain info width pixels of Color_Type, or is zero. If rowBytes is not zero, subsequent images returned by makeImageSnapshot have the same rowBytes. #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Raster_Surface; width and height must be greater than zero ## #Param rowBytes interval from one Surface row to the next; may be zero ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example void draw(SkCanvas* ) { SkImageInfo info = SkImageInfo::MakeN32Premul(3, 3); const size_t rowBytes = 64; sk_sp surface(SkSurface::MakeRaster(info, rowBytes, nullptr)); SkCanvas* canvas = surface->getCanvas(); canvas->clear(SK_ColorWHITE); SkPixmap pixmap; if (surface->peekPixels(&pixmap)) { const uint32_t* colorPtr = pixmap.addr32(); SkPMColor pmWhite = colorPtr[0]; SkPaint paint; canvas->drawPoint(1, 1, paint); canvas->flush(); // ensure that point was drawn for (int y = 0; y < info.height(); ++y) { for (int x = 0; x < info.width(); ++x) { SkDebugf("%c", colorPtr[x] == pmWhite ? '-' : 'x'); } colorPtr += rowBytes / sizeof(colorPtr[0]); SkDebugf("\n"); } } } #StdOut --- -x- --- ## ## #SeeAlso MakeRasterDirect MakeRasterN32Premul MakeRasterDirectReleaseProc #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRaster(const SkImageInfo& imageInfo, const SkSurfaceProps* props = nullptr) Allocates raster Surface. Canvas returned by Surface draws directly into pixels. Allocates and zeroes pixel memory. Pixel memory size is imageInfo.height() times imageInfo.minRowBytes(). Pixel memory is deleted when Surface is deleted. Surface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains Color_Type and Alpha_Type supported by Raster_Surface. #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Raster_Surface; width and height must be greater than zero ## #Param props LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example void draw(SkCanvas* ) { SkImageInfo info = SkImageInfo::MakeN32Premul(3, 3); sk_sp surface(SkSurface::MakeRaster(info)); SkCanvas* canvas = surface->getCanvas(); canvas->clear(SK_ColorWHITE); SkPixmap pixmap; if (surface->peekPixels(&pixmap)) { const uint32_t* colorPtr = pixmap.addr32(); SkPMColor pmWhite = colorPtr[0]; SkPaint paint; canvas->drawPoint(1, 1, paint); canvas->flush(); // ensure that point was drawn for (int y = 0; y < info.height(); ++y) { for (int x = 0; x < info.width(); ++x) { SkDebugf("%c", colorPtr[x] == pmWhite ? '-' : 'x'); } colorPtr += info.width(); SkDebugf("\n"); } } } ## #SeeAlso MakeRasterDirect MakeRasterN32Premul MakeRasterDirectReleaseProc #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRasterN32Premul(int width, int height, const SkSurfaceProps* surfaceProps = nullptr) #In Constructor #Line # creates Surface from width, height matching output ## Allocates raster Surface. Canvas returned by Surface draws directly into pixels. Allocates and zeroes pixel memory. Pixel memory size is height times width times four. Pixel memory is deleted when Surface is deleted. Internally, sets Image_Info to width, height, Native_Color_Type, and kPremul_SkAlphaType. Surface is returned if width and height are greater than zero. Use to create Surface that matches SkPMColor, the native pixel arrangement on the platform. Surface drawn to output device skips converting its pixel format. #Param width pixel column count; must be greater than zero ## #Param height pixel row count; must be greater than zero ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example void draw(SkCanvas* ) { sk_sp surface(SkSurface::MakeRasterN32Premul(3, 3)); SkCanvas* canvas = surface->getCanvas(); canvas->clear(SK_ColorWHITE); SkPixmap pixmap; if (surface->peekPixels(&pixmap)) { const uint32_t* colorPtr = pixmap.addr32(); SkPMColor pmWhite = colorPtr[0]; SkPaint paint; canvas->drawPoint(1, 1, paint); canvas->flush(); // ensure that point was drawn for (int y = 0; y < surface->height(); ++y) { for (int x = 0; x < surface->width(); ++x) { SkDebugf("%c", colorPtr[x] == pmWhite ? '-' : 'x'); } colorPtr += surface->width(); SkDebugf("\n"); } } } #StdOut --- -x- --- ## ## #SeeAlso MakeRasterDirect MakeRasterN32Premul MakeRasterDirectReleaseProc #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeFromBackendTexture(GrContext* context, const GrBackendTexture& backendTexture, GrSurfaceOrigin origin, int sampleCnt, SkColorType colorType, sk_sp colorSpace, const SkSurfaceProps* surfaceProps) #In Constructor #Line # creates Surface from GPU texture ## Wraps a GPU-backed texture into Surface. Caller must ensure the texture is valid for the lifetime of returned Surface. If sampleCnt greater than zero, creates an intermediate MSAA Surface which is used for drawing backendTexture. Surface is returned if all parameters are valid. backendTexture is valid if its pixel configuration agrees with colorSpace and context; for instance, if backendTexture has an sRGB configuration, then context must support sRGB, and colorSpace must be present. Further, backendTexture width and height must not exceed context capabilities, and the context must be able to support back-end textures. If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr. #Param context GPU_Context ## #Param backendTexture texture residing on GPU ## #Param origin one of: kBottomLeft_GrSurfaceOrigin, kTopLeft_GrSurfaceOrigin ## #Param sampleCnt samples per pixel, or 0 to disable full scene anti-aliasing ## #Param colorType one of: #list_of_color_types# ## #Param colorSpace range of colors; may be nullptr ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example #Platform gpu cpu #Image 3 SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } sk_sp gpuSurface = SkSurface::MakeFromBackendTexture(context, backEndTexture, kTopLeft_GrSurfaceOrigin, 0, kRGBA_8888_SkColorType, nullptr, nullptr); auto surfaceCanvas = gpuSurface->getCanvas(); surfaceCanvas->drawString("GPU rocks!", 20, 40, paint); sk_sp image(gpuSurface->makeImageSnapshot()); canvas->drawImage(image, 0, 0); ## #SeeAlso GrBackendTexture MakeFromBackendRenderTarget MakeRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeFromBackendRenderTarget(GrContext* context, const GrBackendRenderTarget& backendRenderTarget, GrSurfaceOrigin origin, SkColorType colorType, sk_sp colorSpace, const SkSurfaceProps* surfaceProps) #In Constructor #Line # creates Surface from GPU render target ## Wraps a GPU-backed buffer into Surface. Caller must ensure backendRenderTarget is valid for the lifetime of returned Surface. Surface is returned if all parameters are valid. backendRenderTarget is valid if its pixel configuration agrees with colorSpace and context; for instance, if backendRenderTarget has an sRGB configuration, then context must support sRGB, and colorSpace must be present. Further, backendRenderTarget width and height must not exceed context capabilities, and the context must be able to support back-end render targets. If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr. #Param context GPU_Context ## #Param backendRenderTarget GPU intermediate memory buffer ## #Param origin one of: kBottomLeft_GrSurfaceOrigin, kTopLeft_GrSurfaceOrigin ## #Param colorType one of: #list_of_color_types# ## #Param colorSpace range of colors ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example #ToDo remove !fiddle below once backEndTextureRenderTarget is available ## #Platform !fiddle gpu SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } sk_sp gpuSurface = SkSurface::MakeFromBackendRenderTarget(context, backEndRenderTarget, kTopLeft_GrSurfaceOrigin, kRGBA_8888_SkColorType, nullptr, nullptr); auto surfaceCanvas = gpuSurface->getCanvas(); surfaceCanvas->drawString("GPU rocks!", 20, 40, paint); sk_sp image(gpuSurface->makeImageSnapshot()); canvas->drawImage(image, 0, 0); ## #SeeAlso MakeFromBackendTexture MakeRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeFromBackendTextureAsRenderTarget(GrContext* context, const GrBackendTexture& backendTexture, GrSurfaceOrigin origin, int sampleCnt, SkColorType colorType, sk_sp colorSpace, const SkSurfaceProps* surfaceProps) #In Constructor #Line # creates Surface from GPU back-end render target ## Wraps a GPU-backed texture into Surface. Caller must ensure backendTexture is valid for the lifetime of returned Surface. If sampleCnt greater than zero, creates an intermediate MSAA Surface which is used for drawing backendTexture. Surface is returned if all parameters are valid. backendTexture is valid if its pixel configuration agrees with colorSpace and context; for instance, if backendTexture has an sRGB configuration, then context must support sRGB, and colorSpace must be present. Further, backendTexture width and height must not exceed context capabilities. Returned Surface is available only for drawing into, and cannot generate an Image. If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr. #Param context GPU_Context ## #Param backendTexture texture residing on GPU ## #Param origin one of: kBottomLeft_GrSurfaceOrigin, kTopLeft_GrSurfaceOrigin ## #Param sampleCnt samples per pixel, or 0 to disable full scene anti-aliasing ## #Param colorType one of: #list_of_color_types# ## #Param colorSpace range of colors; may be nullptr ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example #ToDo example is bogus; gpuSurface should not make image ## #Platform gpu #Image 3 SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } sk_sp gpuSurface = SkSurface::MakeFromBackendTextureAsRenderTarget( context, backEndTexture, kTopLeft_GrSurfaceOrigin, 0, kRGBA_8888_SkColorType, nullptr, nullptr); auto surfaceCanvas = gpuSurface->getCanvas(); surfaceCanvas->drawString("GPU rocks!", 20, 40, paint); sk_sp image(gpuSurface->makeImageSnapshot()); canvas->drawImage(image, 0, 0); ## #SeeAlso MakeFromBackendRenderTarget MakeRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRenderTarget(GrContext* context, SkBudgeted budgeted, const SkImageInfo& imageInfo, int sampleCount, GrSurfaceOrigin surfaceOrigin, const SkSurfaceProps* surfaceProps, bool shouldCreateWithMips = false) #In Constructor #Line # creates Surface pointing to new GPU memory buffer ## Returns Surface on GPU indicated by context. Allocates memory for pixels, based on the width, height, and Color_Type in ImageInfo. budgeted selects whether allocation for pixels is tracked by context. imageInfo describes the pixel format in Color_Type, and transparency in Alpha_Type, and color matching in Color_Space. sampleCount requests the number of samples per pixel. Pass zero to disable Multi_Sample_Anti_Aliasing. The request is rounded up to the next supported count, or rounded down if it is larger than the maximum supported count. surfaceOrigin pins either the top-left or the bottom-left corner to the origin. shouldCreateWithMips hints that Image returned by makeImageSnapshot is Mip_Map. If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr. #Param context GPU_Context ## #Param budgeted one of: SkBudgeted::kNo, SkBudgeted::kYes ## #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space; width, or height, or both, may be zero ## #Param sampleCount samples per pixel, or 0 to disable full scene anti-aliasing ## #Param surfaceOrigin one of: kBottomLeft_GrSurfaceOrigin, kTopLeft_GrSurfaceOrigin ## #Param surfaceProps LCD striping orientation and setting for device independent fonts; may be nullptr ## #Param shouldCreateWithMips hint that Surface will host Mip_Map images ## #Return Surface if all parameters are valid; otherwise, nullptr ## #ToDo not sure that this example is relevant; surfaceOrigin doesn't appear to do anything ## #Example #Platform gpu #Height 64 SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } SkImageInfo info = SkImageInfo::MakeN32(256, 64, kOpaque_SkAlphaType); for (auto surfaceOrigin : { kTopLeft_GrSurfaceOrigin, kBottomLeft_GrSurfaceOrigin } ) { auto gpuSurface(SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, info, 0, surfaceOrigin, nullptr)); auto surfaceCanvas = gpuSurface->getCanvas(); surfaceCanvas->clear(SK_ColorWHITE); surfaceCanvas->drawString("GPU rocks!", 20, 40, paint); sk_sp image(gpuSurface->makeImageSnapshot()); canvas->drawImage(image, 0, 0); canvas->translate(0, 128); } ## #SeeAlso MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRenderTarget(GrContext* context, SkBudgeted budgeted, const SkImageInfo& imageInfo, int sampleCount, const SkSurfaceProps* props) Returns Surface on GPU indicated by context. Allocates memory for pixels, based on the width, height, and Color_Type in ImageInfo. budgeted selects whether allocation for pixels is tracked by context. imageInfo describes the pixel format in Color_Type, and transparency in Alpha_Type, and color matching in Color_Space. sampleCount requests the number of samples per pixel. Pass zero to disable Multi_Sample_Anti_Aliasing. The request is rounded up to the next supported count, or rounded down if it is larger than the maximum supported count. Surface bottom-left corner is pinned to the origin. #Param context GPU_Context ## #Param budgeted one of: SkBudgeted::kNo, SkBudgeted::kYes ## #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Raster_Surface; width, or height, or both, may be zero ## #Param sampleCount samples per pixel, or 0 to disable Multi_Sample_Anti_Aliasing ## #Param props LCD striping orientation and setting for device independent fonts; may be nullptr ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example #Platform cpu gpu #Description LCD text takes advantage of raster striping to improve resolution. Only one of the four combinations is correct, depending on whether monitor LCD striping is horizontal or vertical, and whether the order of the stripes is red blue green or red green blue. ## void draw(SkCanvas* canvas) { auto test_draw = [](SkCanvas* surfaceCanvas) -> void { SkPaint paint; paint.setAntiAlias(true); paint.setLCDRenderText(true); paint.setColor(0xFFBBBBBB); surfaceCanvas->drawRect(SkRect::MakeWH(128, 64), paint); paint.setColor(SK_ColorWHITE); paint.setTextSize(32); surfaceCanvas->drawString("Pest", 0, 25, paint); }; GrContext* context = canvas->getGrContext(); SkImageInfo info = SkImageInfo::MakeN32(128, 64, kOpaque_SkAlphaType); int y = 0; for (auto geometry : { kRGB_H_SkPixelGeometry, kBGR_H_SkPixelGeometry, kRGB_V_SkPixelGeometry, kBGR_V_SkPixelGeometry } ) { SkSurfaceProps props(0, geometry); sk_sp surface = context ? SkSurface::MakeRenderTarget( context, SkBudgeted::kNo, info, 0, &props) : SkSurface::MakeRaster(info, &props); test_draw(surface->getCanvas()); surface->draw(canvas, 0, y, nullptr); sk_sp image(surface->makeImageSnapshot()); SkAutoCanvasRestore acr(canvas, true); canvas->scale(8, 8); canvas->drawImage(image, 12, y / 8); y += 64; } } ## #SeeAlso MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRenderTarget(GrContext* context, SkBudgeted budgeted, const SkImageInfo& imageInfo) Returns Surface on GPU indicated by context. Allocates memory for pixels, based on the width, height, and Color_Type in ImageInfo. budgeted selects whether allocation for pixels is tracked by context. imageInfo describes the pixel format in Color_Type, and transparency in Alpha_Type, and color matching in Color_Space. Surface bottom-left corner is pinned to the origin. #Param context GPU_Context ## #Param budgeted one of: SkBudgeted::kNo, SkBudgeted::kYes ## #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Raster_Surface; width, or height, or both, may be zero ## #Return Surface if all parameters are valid; otherwise, nullptr ## #Example #Platform gpu SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } SkImageInfo info = SkImageInfo::MakeN32(256, 64, kOpaque_SkAlphaType); auto gpuSurface(SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, info)); auto surfaceCanvas = gpuSurface->getCanvas(); surfaceCanvas->clear(SK_ColorWHITE); surfaceCanvas->drawString("GPU rocks!", 20, 40, paint); sk_sp image(gpuSurface->makeImageSnapshot()); canvas->drawImage(image, 0, 0); ## #SeeAlso MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeRenderTarget(GrContext* context, const SkSurfaceCharacterization& characterization, SkBudgeted budgeted) Returns SkSurface on GPU indicated by context that is compatible with the provided characterization. budgeted selects whether allocation for pixels is tracked by context. #Param context GPU_Context ## #Param characterization description of the desired SkSurface ## #Param budgeted one of: SkBudgeted::kNo, SkBudgeted::kYes ## #Return Surface if all parameters are valid; otherwise, nullptr ## #NoExample ## #SeeAlso MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method static sk_sp MakeNull(int width, int height) #In Constructor #Line # creates Surface without backing pixels ## Returns Surface without backing pixels. Drawing to Canvas returned from Surface has no effect. Calling makeImageSnapshot() on returned Surface returns nullptr. #Param width one or greater ## #Param height one or greater ## #Return Surface if width and height are positive; otherwise, nullptr ## #Example SkDebugf("SkSurface::MakeNull(0, 0) %c= nullptr\n", SkSurface::MakeNull(0, 0) == nullptr ? '=' : '!'); const int w = 37; const int h = 1000; auto surf = SkSurface::MakeNull(w, h); auto nullCanvas = surf->getCanvas(); nullCanvas->drawPaint(SkPaint()); // does not crash, nothing draws SkDebugf("surf->makeImageSnapshot() %c= nullptr\n", surf->makeImageSnapshot() == nullptr ? '=' : '!'); #StdOut SkSurface::MakeNull(0, 0) == nullptr surf->makeImageSnapshot() == nullptr ## ## #SeeAlso MakeRaster MakeRenderTarget #Method ## # ------------------------------------------------------------------------------ #Subtopic Property #Populate #Line # member values ## ## #Method int width() const #In Property #Line # returns pixel column count ## Returns pixel count in each row; may be zero or greater. #Return number of pixel columns ## #Example const int width = 37; const int height = 1000; auto surf = SkSurface::MakeNull(width, height); auto nullCanvas = surf->getCanvas(); SkDebugf("surface width=%d canvas width=%d\n", surf->width(), nullCanvas->getBaseLayerSize().fWidth); #StdOut surface width=37 canvas width=37 ## ## #SeeAlso height() #Method ## # ------------------------------------------------------------------------------ #Method int height() const #In Property #Line # returns pixel row count ## Returns pixel row count; may be zero or greater. #Return number of pixel rows ## #Example const int width = 37; const int height = 1000; auto surf = SkSurface::MakeNull(width, height); auto nullCanvas = surf->getCanvas(); SkDebugf("surface height=%d canvas height=%d\n", surf->height(), nullCanvas->getBaseLayerSize().fHeight); #StdOut surface height=1000 canvas height=1000 ## ## #SeeAlso width() #Method ## # ------------------------------------------------------------------------------ #Method uint32_t generationID() #In Property #Line # returns unique ID ## Returns unique value identifying the content of Surface. Returned value changes each time the content changes. Content is changed by drawing, or by calling notifyContentWillChange. #Return unique content identifier ## #Example auto surface = SkSurface::MakeRasterN32Premul(1, 1); for (int i = 0; i < 3; ++i) { SkDebugf("surface generationID: %d\n", surface->generationID()); if (0 == i) { surface->getCanvas()->drawColor(SK_ColorBLACK); } else { surface->notifyContentWillChange(SkSurface::kDiscard_ContentChangeMode); } } #StdOut surface generationID: 1 surface generationID: 2 surface generationID: 3 ## ## #SeeAlso notifyContentWillChange ContentChangeMode getCanvas #Method ## # ------------------------------------------------------------------------------ #Enum ContentChangeMode #Line # parameter options for notifyContentWillChange ## #Code enum ContentChangeMode { kDiscard_ContentChangeMode, kRetain_ContentChangeMode, }; ## ContentChangeMode members are parameters to notifyContentWillChange. #Const kDiscard_ContentChangeMode #Line # discards surface on change ## Pass to notifyContentWillChange to discard surface contents when the surface is cleared or overwritten. ## #Const kRetain_ContentChangeMode #Line # preserves surface on change ## Pass to notifyContentWillChange when to preserve surface contents. If a snapshot has been generated, this copies the Surface contents. ## #SeeAlso notifyContentWillChange generationID #Enum ## # ------------------------------------------------------------------------------ #ToDo not crazy about misc catagory -- hopefully will become clear with time ## #Subtopic Miscellaneous #Populate #Line # other functions ## ## #Method void notifyContentWillChange(ContentChangeMode mode) #In Miscellaneous #Line # notifies that contents will be changed outside of Skia ## Notifies that Surface contents will be changed by code outside of Skia. Subsequent calls to generationID return a different value. mode is normally passed as kRetain_ContentChangeMode. #Private Can we deprecate this? ## #Param mode one of: kDiscard_ContentChangeMode, kRetain_ContentChangeMode ## #Example auto surface = SkSurface::MakeRasterN32Premul(1, 1); for (int i = 0; i < 3; ++i) { SkDebugf("surface generationID: %d\n", surface->generationID()); if (0 == i) { surface->getCanvas()->drawColor(SK_ColorBLACK); } else { surface->notifyContentWillChange(SkSurface::kDiscard_ContentChangeMode); } } ## #SeeAlso ContentChangeMode generationID #Method ## # ------------------------------------------------------------------------------ #Enum BackendHandleAccess #Line # options to read and write back-end object ## #Code enum BackendHandleAccess { kFlushRead_BackendHandleAccess, kFlushWrite_BackendHandleAccess, kDiscardWrite_BackendHandleAccess, }; static const BackendHandleAccess kFlushRead_TextureHandleAccess = kFlushRead_BackendHandleAccess; static const BackendHandleAccess kFlushWrite_TextureHandleAccess = kFlushWrite_BackendHandleAccess; static const BackendHandleAccess kDiscardWrite_TextureHandleAccess = kDiscardWrite_BackendHandleAccess; ## #Const kFlushRead_BackendHandleAccess 0 #Line # back-end object is readable ## Caller may read from the back-end object. ## #Const kFlushWrite_BackendHandleAccess 1 #Line # back-end object is writable ## Caller may write to the back-end object. ## #Const kDiscardWrite_BackendHandleAccess 2 #Line # back-end object must be overwritten ## Caller must overwrite the entire back-end object. ## #Const kFlushRead_TextureHandleAccess 0 #Deprecated ## #Const kFlushWrite_TextureHandleAccess 1 #Deprecated ## #Const kDiscardWrite_TextureHandleAccess 2 #Deprecated ## #NoExample // todo: need to update example to use GrBackendTexture instead of GrBackendObject #Platform gpu SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } sk_sp gpuSurface = SkSurface::MakeRenderTarget( context, SkBudgeted::kYes, SkImageInfo::MakeN32Premul(10, 10)); int y = 20; SkString str; paint.setTextSize(16); for (auto access : { SkSurface::kFlushRead_BackendHandleAccess, SkSurface::kFlushWrite_BackendHandleAccess, SkSurface::kDiscardWrite_BackendHandleAccess } ) { sk_sp image(gpuSurface->makeImageSnapshot()); str.printf("uniqueID=%d", image->uniqueID()); canvas->drawString(str, 20, y += 20, paint); GrBackendTexture backendTex = gpuSurface->getBackendTexture(access); str.printf("backendTex is %svalid", backendTex.isValid() ? '' : 'not '); canvas->drawString(str, 20, y += 20, paint); } sk_sp image(gpuSurface->makeImageSnapshot()); str.printf("final image uniqueID=%d", image->uniqueID()); canvas->drawString(str, 20, y += 20, paint); ## #SeeAlso getBackendTexture getBackendRenderTarget #Enum ## # ------------------------------------------------------------------------------ #Method GrBackendTexture getBackendTexture(BackendHandleAccess backendHandleAccess) #In Property #Line # returns the GPU reference to texture ## Retrieves the back-end texture. If Surface has no back-end texture, an invalid object is returned. Call GrBackendTexture::isValid to determine if the result is valid. The returned GrBackendTexture should be discarded if the Surface is drawn to or deleted. #Param backendHandleAccess one of: kFlushRead_BackendHandleAccess, kFlushWrite_BackendHandleAccess, kDiscardWrite_BackendHandleAccess ## #Return GPU texture reference; invalid on failure ## #NoExample ## #SeeAlso GrBackendTexture BackendHandleAccess getBackendRenderTarget #Method ## # ------------------------------------------------------------------------------ #Method GrBackendRenderTarget getBackendRenderTarget(BackendHandleAccess backendHandleAccess) #In Property #Line # returns the GPU reference to render target ## Retrieves the back-end render target. If Surface has no back-end render target, an invalid object is returned. Call GrBackendRenderTarget::isValid to determine if the result is valid. The returned GrBackendRenderTarget should be discarded if the Surface is drawn to or deleted. #Param backendHandleAccess one of: kFlushRead_BackendHandleAccess, kFlushWrite_BackendHandleAccess, kDiscardWrite_BackendHandleAccess ## #Return GPU render target reference; invalid on failure ## #NoExample ## #SeeAlso GrBackendRenderTarget BackendHandleAccess getBackendTexture #Method ## # ------------------------------------------------------------------------------ #Method SkCanvas* getCanvas() #In Property #Line # returns Canvas that draws into Surface ## Returns Canvas that draws into Surface. Subsequent calls return the same Canvas. Canvas returned is managed and owned by Surface, and is deleted when Surface is deleted. #Return drawing Canvas for Surface ## #Example #Height 64 sk_sp surface(SkSurface::MakeRasterN32Premul(64, 64)); SkCanvas* surfaceCanvas = surface->getCanvas(); surfaceCanvas->clear(SK_ColorBLUE); SkPaint paint; paint.setTextSize(40); surfaceCanvas->drawString("\xF0\x9F\x98\x81", 12, 45, paint); surface->draw(canvas, 0, 0, nullptr); ## #SeeAlso makeSurface makeImageSnapshot draw #Method ## # ------------------------------------------------------------------------------ #Method sk_sp makeSurface(const SkImageInfo& imageInfo) #In Constructor #Line # creates a compatible Surface ## Returns a compatible Surface, or nullptr. Returned Surface contains the same raster, GPU, or null properties as the original. Returned Surface does not share the same pixels. Returns nullptr if imageInfo width or height are zero, or if imageInfo is incompatible with Surface. #Param imageInfo width, height, Color_Type, Alpha_Type, Color_Space, of Surface; width and height must be greater than zero ## #Return compatible Surface or nullptr ## #Example #Height 96 sk_sp big(SkSurface::MakeRasterN32Premul(64, 64)); sk_sp lil(big->makeSurface(SkImageInfo::MakeN32(32, 32, kPremul_SkAlphaType))); big->getCanvas()->clear(SK_ColorRED); lil->getCanvas()->clear(SK_ColorBLACK); SkPixmap pixmap; if (big->peekPixels(&pixmap)) { SkBitmap bigBits; bigBits.installPixels(pixmap); canvas->drawBitmap(bigBits, 0, 0); } if (lil->peekPixels(&pixmap)) { SkBitmap lilBits; lilBits.installPixels(pixmap); canvas->drawBitmap(lilBits, 64, 64); } ## #SeeAlso makeImageSnapshot getCanvas draw #Method ## # ------------------------------------------------------------------------------ #Method sk_sp makeImageSnapshot() #In Constructor #Line # creates Image capturing Surface contents ## Returns Image capturing Surface contents. Subsequent drawing to Surface contents are not captured. Image allocation is accounted for if Surface was created with SkBudgeted::kYes. #Return Image initialized with Surface contents ## #Example #Height 64 sk_sp big(SkSurface::MakeRasterN32Premul(64, 64)); sk_sp lil(big->makeSurface(SkImageInfo::MakeN32(32, 32, kPremul_SkAlphaType))); big->getCanvas()->clear(SK_ColorRED); lil->getCanvas()->clear(SK_ColorBLACK); sk_sp early(big->makeImageSnapshot()); lil->draw(big->getCanvas(), 16, 16, nullptr); sk_sp later(big->makeImageSnapshot()); canvas->drawImage(early, 0, 0); canvas->drawImage(later, 128, 0); ## #SeeAlso draw getCanvas #Method ## # ------------------------------------------------------------------------------ #Subtopic Pixels #Populate #Line # functions with pixel access ## ## #Method void draw(SkCanvas* canvas, SkScalar x, SkScalar y, const SkPaint* paint) #In Pixels #Line # draws Surface contents to canvas ## Draws Surface contents to canvas, with its top-left corner at (x, y). If Paint paint is not nullptr, apply Color_Filter, Color_Alpha, Image_Filter, Blend_Mode, and Draw_Looper. #Param canvas Canvas drawn into ## #Param x horizontal offset in Canvas ## #Param y vertical offset in Canvas ## #Param paint Paint containing Blend_Mode, Color_Filter, Image_Filter, and so on; or nullptr ## #Example #Height 64 sk_sp big(SkSurface::MakeRasterN32Premul(64, 64)); sk_sp lil(big->makeSurface(SkImageInfo::MakeN32(32, 32, kPremul_SkAlphaType))); big->getCanvas()->clear(SK_ColorRED); lil->getCanvas()->clear(SK_ColorBLACK); lil->draw(big->getCanvas(), 16, 16, nullptr); SkPixmap pixmap; if (big->peekPixels(&pixmap)) { SkBitmap bigBits; bigBits.installPixels(pixmap); canvas->drawBitmap(bigBits, 0, 0); } ## #SeeAlso makeImageSnapshot getCanvas #Method ## # ------------------------------------------------------------------------------ #Method bool peekPixels(SkPixmap* pixmap) #In Pixels #Line # copies Surface parameters to Pixmap ## Copies Surface pixel address, row bytes, and Image_Info to Pixmap, if address is available, and returns true. If pixel address is not available, return false and leave Pixmap unchanged. pixmap contents become invalid on any future change to Surface. #Param pixmap storage for pixel state if pixels are readable; otherwise, ignored ## #Return true if Surface has direct access to pixels ## #Example #Height 64 sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); auto surfCanvas = surf->getCanvas(); surfCanvas->clear(SK_ColorRED); SkPaint paint; paint.setTextSize(40); surfCanvas->drawString("&", 16, 48, paint); SkPixmap pixmap; if (surf->peekPixels(&pixmap)) { SkBitmap surfBits; surfBits.installPixels(pixmap); canvas->drawBitmap(surfBits, 0, 0); } ## #SeeAlso readPixels writePixels #Method ## # ------------------------------------------------------------------------------ #Method bool readPixels(const SkPixmap& dst, int srcX, int srcY) #In Pixels #Line # copies Rect of pixels ## Copies Rect of pixels to dst. Source Rect corners are (srcX, srcY) and Surface (width(), height()). Destination Rect corners are (0, 0) and (dst.width(), dst.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to dst.colorType() and dst.alphaType() if required. Pixels are readable when Surface is raster, or backed by a GPU. The destination pixel storage must be allocated by the caller. Pixel values are converted only if Color_Type and Alpha_Type do not match. Only pixels within both source and destination rectangles are copied. dst contents outside Rect intersection are unchanged. Pass negative values for srcX or srcY to offset pixels across or down destination. Does not copy, and returns false if: #List # Source and destination rectangles do not intersect. ## # Pixmap pixels could not be allocated. ## # dst.rowBytes() is too small to contain one row of pixels. ## ## #Param dst storage for pixels copied from Surface ## #Param srcX offset into readable pixels on x-axis; may be negative ## #Param srcY offset into readable pixels on y-axis; may be negative ## #Return true if pixels were copied ## #Example #Height 32 sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); auto surfCanvas = surf->getCanvas(); surfCanvas->clear(SK_ColorRED); SkPaint paint; paint.setTextSize(40); surfCanvas->drawString("&", 0, 32, paint); std::vector storage; storage.resize(surf->width() * surf->height()); SkPixmap pixmap(SkImageInfo::MakeN32Premul(32, 32), &storage.front(), surf->width() * sizeof(storage[0])); if (surf->readPixels(pixmap, 0, 0)) { SkBitmap surfBits; surfBits.installPixels(pixmap); canvas->drawBitmap(surfBits, 0, 0); } ## #SeeAlso peekPixels writePixels #Method ## # ------------------------------------------------------------------------------ #Method bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes, int srcX, int srcY) Copies Rect of pixels from Canvas into dstPixels. Source Rect corners are (srcX, srcY) and Surface (width(), height()). Destination Rect corners are (0, 0) and (dstInfo.width(), dstInfo.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to dstInfo.colorType() and dstInfo.alphaType() if required. Pixels are readable when Surface is raster, or backed by a GPU. The destination pixel storage must be allocated by the caller. Pixel values are converted only if Color_Type and Alpha_Type do not match. Only pixels within both source and destination rectangles are copied. dstPixels contents outside Rect intersection are unchanged. Pass negative values for srcX or srcY to offset pixels across or down destination. Does not copy, and returns false if: #List # Source and destination rectangles do not intersect. ## # Surface pixels could not be converted to dstInfo.colorType() or dstInfo.alphaType(). ## # dstRowBytes is too small to contain one row of pixels. ## ## #Param dstInfo width, height, Color_Type, and Alpha_Type of dstPixels ## #Param dstPixels storage for pixels; dstInfo.height() times dstRowBytes, or larger ## #Param dstRowBytes size of one destination row; dstInfo.width() times pixel size, or larger ## #Param srcX offset into readable pixels on x-axis; may be negative ## #Param srcY offset into readable pixels on y-axis; may be negative ## #Return true if pixels were copied ## #Example #Height 64 #Description A black oval drawn on a red background provides an image to copy. readPixels copies one quarter of the Surface into each of the four corners. The copied quarter ovals overdraw the original oval. ## sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); auto surfCanvas = surf->getCanvas(); surfCanvas->clear(SK_ColorRED); SkPaint paint; surfCanvas->drawOval({4, 8, 58, 54}, paint); SkImageInfo info = SkImageInfo::Make(64, 64, kBGRA_8888_SkColorType, kPremul_SkAlphaType); sk_sp data(SkData::MakeUninitialized(info.minRowBytes() * info.height())); sk_bzero(data->writable_data(), info.minRowBytes() * info.height()); for (int x : { 32, -32 } ) { for (int y : { 32, -32 } ) { surf->readPixels(info, data->writable_data(), info.minRowBytes(), x, y); } } sk_sp image = SkImage::MakeRasterData(info, data, info.minRowBytes()); canvas->drawImage(image, 0, 0); ## #SeeAlso peekPixels writePixels #Method ## # ------------------------------------------------------------------------------ #Method bool readPixels(const SkBitmap& dst, int srcX, int srcY) Copies Rect of pixels from Surface into bitmap. Source Rect corners are (srcX, srcY) and Surface (width(), height()). Destination Rect corners are (0, 0) and (bitmap.width(), bitmap.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to bitmap.colorType() and bitmap.alphaType() if required. Pixels are readable when Surface is raster, or backed by a GPU. The destination pixel storage must be allocated by the caller. Pixel values are converted only if Color_Type and Alpha_Type do not match. Only pixels within both source and destination rectangles are copied. dst contents outside Rect intersection are unchanged. Pass negative values for srcX or srcY to offset pixels across or down destination. Does not copy, and returns false if: #List # Source and destination rectangles do not intersect. ## # Surface pixels could not be converted to dst.colorType() or dst.alphaType(). ## # dst pixels could not be allocated. ## # dst.rowBytes() is too small to contain one row of pixels. ## ## #Param dst storage for pixels copied from Surface ## #Param srcX offset into readable pixels on x-axis; may be negative ## #Param srcY offset into readable pixels on y-axis; may be negative ## #Return true if pixels were copied ## #Example sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); auto surfCanvas = surf->getCanvas(); surfCanvas->clear(SK_ColorGREEN); SkPaint paint; surfCanvas->drawOval({2, 10, 58, 54}, paint); SkImageInfo info = SkImageInfo::Make(64, 64, kBGRA_8888_SkColorType, kPremul_SkAlphaType); SkBitmap bitmap; bitmap.setInfo(info); bitmap.allocPixels(); for (int x : { 32, -32 } ) { for (int y : { 32, -32 } ) { surf->readPixels(bitmap, x, y); } } canvas->drawBitmap(bitmap, 0, 0); ## #SeeAlso peekPixels writePixels #Method ## # ------------------------------------------------------------------------------ #Method void writePixels(const SkPixmap& src, int dstX, int dstY) #In Pixels #Line # copies Rect of pixels ## Copies Rect of pixels from the src Pixmap to the Surface. Source Rect corners are (0, 0) and (src.width(), src.height()). Destination Rect corners are (dstX, dstY) and #Formula (dstX + Surface width(), dstY + Surface height()) ## . Copies each readable pixel intersecting both rectangles, without scaling, converting to Surface colorType() and Surface alphaType() if required. #Param src storage for pixels to copy to Surface ## #Param dstX x-axis position relative to Surface to begin copy; may be negative ## #Param dstY y-axis position relative to Surface to begin copy; may be negative ## #Example #Image 4 #Height 96 sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); auto surfCanvas = surf->getCanvas(); surfCanvas->clear(SK_ColorRED); SkPaint paint; paint.setTextSize(40); surfCanvas->drawString("&", 16, 40, paint); SkPixmap pixmap; if (surf->peekPixels(&pixmap)) { surf->writePixels(pixmap, 25, 25); sk_sp image(surf->makeImageSnapshot()); canvas->drawImage(image, 0, 0); } ## #SeeAlso readPixels peekPixels #Method ## # ------------------------------------------------------------------------------ #Method void writePixels(const SkBitmap& src, int dstX, int dstY) Copies Rect of pixels from the src Bitmap to the Surface. Source Rect corners are (0, 0) and (src.width(), src.height()). Destination Rect corners are (dstX, dstY) and #Formula (dstX + Surface width(), dstY + Surface height()) ## . Copies each readable pixel intersecting both rectangles, without scaling, converting to Surface colorType() and Surface alphaType() if required. #Param src storage for pixels to copy to Surface ## #Param dstX x-axis position relative to Surface to begin copy; may be negative ## #Param dstY y-axis position relative to Surface to begin copy; may be negative ## #Example #Image 4 #Height 96 sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); auto surfCanvas = surf->getCanvas(); surfCanvas->clear(SK_ColorGREEN); surf->writePixels(source, 25, 25); sk_sp image(surf->makeImageSnapshot()); canvas->drawImage(image, 0, 0); ## #SeeAlso readPixels peekPixels #Method ## # ------------------------------------------------------------------------------ #Method const SkSurfaceProps& props() const #In Property #Line # returns Surface_Properties ## Returns Surface_Properties for surface. #Return LCD striping orientation and setting for device independent fonts ## #Example const char* names[] = { "Unknown", "RGB_H", "BGR_H", "RGB_V", "BGR_V" }; sk_sp surf(SkSurface::MakeRasterN32Premul(64, 64)); SkDebugf("surf.props(): k%s_SkPixelGeometry\n", names[surf->props().pixelGeometry()]); #StdOut surf.props(): kRGB_H_SkPixelGeometry ## ## #SeeAlso SkSurfaceProps #Method ## # ------------------------------------------------------------------------------ #Method void prepareForExternalIO() #Deprecated soon #Method ## # ------------------------------------------------------------------------------ #Subtopic Utility #Populate #Line # rarely called management functions ## ## #Method void flush() #In Utility #Line # resolves pending I/O ## Issues pending Surface commands to the GPU-backed API and resolves any Surface MSAA. Skia flushes as needed, so it is not necessary to call this if Skia manages drawing and object lifetime. Call when interleaving Skia calls with native GPU calls. #NoExample ## #SeeAlso GrBackendSemaphore #Method ## # ------------------------------------------------------------------------------ #Method GrSemaphoresSubmitted flushAndSignalSemaphores(int numSemaphores, GrBackendSemaphore signalSemaphores[]) #In Utility #Line # resolves pending I/O, and signal ## Issues pending Surface commands to the GPU-backed API and resolves any Surface MSAA. After issuing all commands, signalSemaphores of count numSemaphores semaphores are signaled by the GPU. For each GrBackendSemaphore in signalSemaphores: if GrBackendSemaphore is initialized, the GPU back-end uses the semaphore as is; otherwise, a new semaphore is created and initializes GrBackendSemaphore. The caller must delete the semaphores created and returned in signalSemaphores. GrBackendSemaphore can be deleted as soon as this function returns. If the back-end API is OpenGL only uninitialized Backend_Semaphores are supported. If the back-end API is Vulkan semaphores may be initialized or uninitialized. If uninitialized, created semaphores are valid only with the VkDevice with which they were created. If GrSemaphoresSubmitted::kNo is returned, the GPU back-end did not create or add any semaphores to signal on the GPU; the caller should not instruct the GPU to wait on any of the semaphores. Pending surface commands are flushed regardless of the return result. #Param numSemaphores size of signalSemaphores array ## #Param signalSemaphores array of semaphore containers ## #Return one of: GrSemaphoresSubmitted::kYes, GrSemaphoresSubmitted::kNo ## #NoExample ## #SeeAlso wait GrBackendSemaphore #Method ## # ------------------------------------------------------------------------------ #Method bool wait(int numSemaphores, const GrBackendSemaphore* waitSemaphores) #In Utility #Line # pauses commands until signaled ## Inserts a list of GPU semaphores that the current GPU-backed API must wait on before executing any more commands on the GPU for this surface. Skia will take ownership of the underlying semaphores and delete them once they have been signaled and waited on. If this call returns false, then the GPU back-end will not wait on any passed in semaphores, and the client will still own the semaphores. #Param numSemaphores size of waitSemaphores array ## #Param waitSemaphores array of semaphore containers ## #Return true if GPU is waiting on semaphores ## #NoExample #ToDo this is copy and paste silliness masquerading as an example. Probably need gpu globals and definitely need gpu expertise to make a real example out of this also, note need to replace GrBackendObject with GrBackendTexture ## #Platform gpu #Height 64 SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } GrBackendSemaphore semaphore; sk_sp surface = SkSurface::MakeRenderTarget( context, SkBudgeted::kYes, SkImageInfo::MakeN32Premul(64, 64)); surface->flushAndSignalSemaphores(1, &semaphore); sk_sp image = surface->makeImageSnapshot(); GrBackendTexture backendTex = image->getBackendTexture(false); // unused SkASSERT(backendTex.isValid()); const SkImageInfo childImageInfo = SkImageInfo::Make(64, 64, kRGBA_8888_SkColorType, kPremul_SkAlphaType); sk_sp childSurface(SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, childImageInfo, 0, kTopLeft_GrSurfaceOrigin, nullptr)); GrBackendTexture backendTexture; sk_sp childImage = SkImage::MakeFromTexture(context, backendTexture, // undefined kTopLeft_GrSurfaceOrigin, kPremul_SkAlphaType, nullptr); SkCanvas* childCanvas = childSurface->getCanvas(); childCanvas->clear(SK_ColorRED); childSurface->wait(1, &semaphore); childCanvas->drawImage(childImage, 32, 0); childSurface->draw(canvas, 0, 0, nullptr); ## #SeeAlso flushAndSignalSemaphores GrBackendSemaphore #Method ## # ------------------------------------------------------------------------------ #Method bool characterize(SkSurfaceCharacterization* characterization) const #In Utility #Line # sets Surface_Characterization for threaded GPU processing ## Initializes Surface_Characterization that can be used to perform GPU back-end processing in a separate thread. Typically this is used to divide drawing into multiple tiles. DeferredDisplayListRecorder records the drawing commands for each tile. Return true if Surface supports characterization. Raster_Surface returns false. #Param characterization properties for parallel drawing ## #Return true if supported ## #Example #Platform gpu #Height 64 SkPaint paint; paint.setTextSize(32); GrContext* context = canvas->getGrContext(); if (!context) { canvas->drawString("GPU only!", 20, 40, paint); return; } sk_sp gpuSurface = SkSurface::MakeRenderTarget( context, SkBudgeted::kYes, SkImageInfo::MakeN32Premul(64, 64)); SkSurfaceCharacterization characterization; if (!gpuSurface->characterize(&characterization)) { canvas->drawString("characterization unsupported", 20, 40, paint); return; } // start of threadable work SkDeferredDisplayListRecorder recorder(characterization); SkCanvas* subCanvas = recorder.getCanvas(); subCanvas->clear(SK_ColorGREEN); std::unique_ptr displayList = recorder.detach(); // end of threadable work gpuSurface->draw(displayList.get()); sk_sp img = gpuSurface->makeImageSnapshot(); canvas->drawImage(std::move(img), 0, 0); ## #SeeAlso draw() SkSurfaceCharacterization SkDeferredDisplayList #Method ## # ------------------------------------------------------------------------------ #Method bool draw(SkDeferredDisplayList* deferredDisplayList) Draws deferred display list created using SkDeferredDisplayListRecorder. Has no effect and returns false if Surface_Characterization stored in deferredDisplayList is not compatible with Surface. Raster_Surface returns false. #Param deferredDisplayList drawing commands ## #Return false if deferredDisplayList is not compatible ## #Example #Height 64 #Platform gpu cpu SkPaint paint; paint.setTextSize(16); sk_sp gpuSurface = SkSurface::MakeRasterN32Premul(64, 64); SkSurfaceCharacterization characterization; if (!gpuSurface->characterize(&characterization)) { canvas->drawString("characterization unsupported", 20, 40, paint); return; } // start of threadable work SkDeferredDisplayListRecorder recorder(characterization); SkCanvas* subCanvas = recorder.getCanvas(); subCanvas->clear(SK_ColorGREEN); std::unique_ptr displayList = recorder.detach(); // end of threadable work gpuSurface->draw(displayList.get()); sk_sp img = gpuSurface->makeImageSnapshot(); canvas->drawImage(std::move(img), 0, 0); ## #SeeAlso characterize() SkSurfaceCharacterization SkDeferredDisplayList #Method ## #Class SkSurface ## #Topic Surface ##