| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef GrPathRenderer_DEFINED |
| #define GrPathRenderer_DEFINED |
| |
| #include "include/core/SkRefCnt.h" |
| #include "include/private/GrTypesPriv.h" |
| #include "include/private/SkTArray.h" |
| |
| class GrCaps; |
| class GrClip; |
| class GrHardClip; |
| class GrPaint; |
| class GrRecordingContext; |
| class GrSurfaceDrawContext; |
| class GrRenderTargetProxy; |
| class GrStyledShape; |
| class GrStyle; |
| struct GrUserStencilSettings; |
| struct SkIRect; |
| class SkMatrix; |
| class SkPath; |
| class SkSurfaceProps; |
| |
| /** |
| * Base class for drawing paths into a GrOpsTask. |
| */ |
| class GrPathRenderer : public SkRefCnt { |
| public: |
| GrPathRenderer(); |
| |
| virtual const char* name() const = 0; |
| |
| /** |
| * A caller may wish to use a path renderer to draw a path into the stencil buffer. However, |
| * the path renderer itself may require use of the stencil buffer. Also a path renderer may |
| * use a GrProcessor coverage stage that sets coverage to zero to eliminate pixels that are |
| * covered by bounding geometry but outside the path. These exterior pixels would still be |
| * rendered into the stencil. |
| * |
| * A GrPathRenderer can provide three levels of support for stenciling paths: |
| * 1) kNoRestriction: This is the most general. The caller passes a GrPaint and calls drawPath(). |
| * The path is rendered exactly as the draw state indicates including support |
| * for simultaneous color and stenciling with arbitrary stenciling rules. |
| * Pixels partially covered by AA paths are affected by the stencil settings. |
| * 2) kStencilOnly: The path renderer cannot apply arbitrary stencil rules nor shade and stencil |
| * simultaneously. The path renderer does support the stencilPath() function |
| * which performs no color writes and writes a non-zero stencil value to pixels |
| * covered by the path. |
| * 3) kNoSupport: This path renderer cannot be used to stencil the path. |
| */ |
| enum StencilSupport { |
| kNoSupport_StencilSupport, |
| kStencilOnly_StencilSupport, |
| kNoRestriction_StencilSupport, |
| }; |
| |
| /** |
| * This function is to get the stencil support for a particular path. The path's fill must |
| * not be an inverse type. The path will always be filled and not stroked. |
| * |
| * @param shape the shape that will be drawn. Must be simple fill styled and non-inverse |
| * filled. |
| */ |
| StencilSupport getStencilSupport(const GrStyledShape& shape) const; |
| |
| enum class CanDrawPath { |
| kNo, |
| kAsBackup, // i.e. This renderer is better than SW fallback if no others can draw the path. |
| kYes |
| }; |
| |
| struct CanDrawPathArgs { |
| SkDEBUGCODE(CanDrawPathArgs() { memset(this, 0, sizeof(*this)); }) // For validation. |
| |
| const GrCaps* fCaps; |
| const GrRenderTargetProxy* fProxy; |
| const SkIRect* fClipConservativeBounds; |
| const SkMatrix* fViewMatrix; |
| const GrStyledShape* fShape; |
| const GrPaint* fPaint; |
| const SkSurfaceProps* fSurfaceProps; |
| GrAAType fAAType; |
| |
| // This is only used by GrTessellationPathRenderer |
| bool fHasUserStencilSettings; |
| |
| #ifdef SK_DEBUG |
| void validate() const { |
| SkASSERT(fCaps); |
| SkASSERT(fProxy); |
| SkASSERT(fClipConservativeBounds); |
| SkASSERT(fViewMatrix); |
| SkASSERT(fShape); |
| SkASSERT(fSurfaceProps); |
| } |
| #endif |
| }; |
| |
| /** |
| * Returns how well this path renderer is able to render the given path. Returning kNo or |
| * kAsBackup allows the caller to keep searching for a better path renderer. This function is |
| * called when searching for the best path renderer to draw a path. |
| */ |
| CanDrawPath canDrawPath(const CanDrawPathArgs& args) const { |
| SkDEBUGCODE(args.validate();) |
| return this->onCanDrawPath(args); |
| } |
| |
| struct DrawPathArgs { |
| GrRecordingContext* fContext; |
| GrPaint&& fPaint; |
| const GrUserStencilSettings* fUserStencilSettings; |
| GrSurfaceDrawContext* fSurfaceDrawContext; |
| const GrClip* fClip; |
| const SkIRect* fClipConservativeBounds; |
| const SkMatrix* fViewMatrix; |
| const GrStyledShape* fShape; |
| GrAAType fAAType; |
| bool fGammaCorrect; |
| #ifdef SK_DEBUG |
| void validate() const { |
| SkASSERT(fContext); |
| SkASSERT(fUserStencilSettings); |
| SkASSERT(fSurfaceDrawContext); |
| SkASSERT(fClipConservativeBounds); |
| SkASSERT(fViewMatrix); |
| SkASSERT(fShape); |
| } |
| #endif |
| }; |
| |
| /** |
| * Draws the path into the draw target. If getStencilSupport() would return kNoRestriction then |
| * the subclass must respect the stencil settings. |
| */ |
| bool drawPath(const DrawPathArgs& args); |
| /** |
| * Args to stencilPath(). fAAType cannot be kCoverage. |
| */ |
| struct StencilPathArgs { |
| SkDEBUGCODE(StencilPathArgs() { memset(this, 0, sizeof(*this)); }) // For validation. |
| |
| GrRecordingContext* fContext; |
| GrSurfaceDrawContext* fSurfaceDrawContext; |
| const GrHardClip* fClip; |
| const SkIRect* fClipConservativeBounds; |
| const SkMatrix* fViewMatrix; |
| const GrStyledShape* fShape; |
| GrAA fDoStencilMSAA; |
| |
| SkDEBUGCODE(void validate() const); |
| }; |
| |
| /** |
| * Draws the path to the stencil buffer. Assume the writable stencil bits are already |
| * initialized to zero. The pixels inside the path will have non-zero stencil values afterwards. |
| */ |
| void stencilPath(const StencilPathArgs& args) { |
| SkDEBUGCODE(args.validate();) |
| SkASSERT(kNoSupport_StencilSupport != this->getStencilSupport(*args.fShape)); |
| this->onStencilPath(args); |
| } |
| |
| protected: |
| // Helper for getting the device bounds of a path. Inverse filled paths will have bounds set |
| // by devSize. Non-inverse path bounds will not necessarily be clipped to devSize. |
| static void GetPathDevBounds(const SkPath& path, |
| SkISize devSize, |
| const SkMatrix& matrix, |
| SkRect* bounds); |
| |
| private: |
| /** |
| * Subclass overrides if it has any limitations of stenciling support. |
| */ |
| virtual StencilSupport onGetStencilSupport(const GrStyledShape&) const { |
| return kNoRestriction_StencilSupport; |
| } |
| |
| /** |
| * Subclass implementation of drawPath() |
| */ |
| virtual bool onDrawPath(const DrawPathArgs& args) = 0; |
| |
| /** |
| * Subclass implementation of canDrawPath() |
| */ |
| virtual CanDrawPath onCanDrawPath(const CanDrawPathArgs& args) const = 0; |
| |
| /** |
| * Subclass implementation of stencilPath(). Subclass must override iff it ever returns |
| * kStencilOnly in onGetStencilSupport(). |
| */ |
| virtual void onStencilPath(const StencilPathArgs&); |
| |
| using INHERITED = SkRefCnt; |
| }; |
| |
| #endif |