The Tor Browser: comparison gfx/skia/trunk/src/gpu/GrClipMaskManager.h

--1:000000000000
+:274576e803a0
+/*
+* 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 GrClipMaskManager_DEFINED
+#define GrClipMaskManager_DEFINED
+#include "GrClipMaskCache.h"
+#include "GrContext.h"
+#include "GrDrawState.h"
+#include "GrReducedClip.h"
+#include "GrStencil.h"
+#include "GrTexture.h"
+#include "SkClipStack.h"
+#include "SkDeque.h"
+#include "SkPath.h"
+#include "SkRefCnt.h"
+#include "SkTLList.h"
+#include "SkTypes.h"
+class GrGpu;
+class GrPathRenderer;
+class GrPathRendererChain;
+class GrTexture;
+class SkPath;
+/**
+* The clip mask creator handles the generation of the clip mask. If anti
+* aliasing is requested it will (in the future) generate a single channel
+* (8bit) mask. If no anti aliasing is requested it will generate a 1-bit
+* mask in the stencil buffer. In the non anti-aliasing case, if the clip
+* mask can be represented as a rectangle then scissoring is used. In all
+* cases scissoring is used to bound the range of the clip mask.
+*/
+class GrClipMaskManager : public SkNoncopyable {
+public:
+GrClipMaskManager()
+: fGpu(NULL)
+, fCurrClipMaskType(kNone_ClipMaskType) {
+}
+/**
+* Creates a clip mask if necessary as a stencil buffer or alpha texture
+* and sets the GrGpu's scissor and stencil state. If the return is false
+* then the draw can be skipped. The AutoRestoreEffects is initialized by
+* the manager when it must install additional effects to implement the
+* clip. devBounds is optional but can help optimize clipping.
+*/
+bool setupClipping(const GrClipData* clipDataIn, GrDrawState::AutoRestoreEffects*,
+const SkRect* devBounds);
+void releaseResources();
+bool isClipInStencil() const {
+return kStencil_ClipMaskType == fCurrClipMaskType;
+}
+bool isClipInAlpha() const {
+return kAlpha_ClipMaskType == fCurrClipMaskType;
+}
+void invalidateStencilMask() {
+if (kStencil_ClipMaskType == fCurrClipMaskType) {
+fCurrClipMaskType = kNone_ClipMaskType;
+}
+}
+GrContext* getContext() {
+return fAACache.getContext();
+}
+void setGpu(GrGpu* gpu);
+void adjustPathStencilParams(GrStencilSettings* settings);
+private:
+/**
+* Informs the helper function adjustStencilParams() about how the stencil
+* buffer clip is being used.
+*/
+enum StencilClipMode {
+// Draw to the clip bit of the stencil buffer
+kModifyClip_StencilClipMode,
+// Clip against the existing representation of the clip in the high bit
+// of the stencil buffer.
+kRespectClip_StencilClipMode,
+// Neither writing to nor clipping against the clip bit.
+kIgnoreClip_StencilClipMode,
+};
+GrGpu* fGpu;
+/**
+* We may represent the clip as a mask in the stencil buffer or as an alpha
+* texture. It may be neither because the scissor rect suffices or we
+* haven't yet examined the clip.
+*/
+enum ClipMaskType {
+kNone_ClipMaskType,
+kStencil_ClipMaskType,
+kAlpha_ClipMaskType,
+} fCurrClipMaskType;
+GrClipMaskCache fAACache;       // cache for the AA path
+// Attempts to install a series of coverage effects to implement the clip. Return indicates
+// whether the element list was successfully converted to effects.
+bool installClipEffects(const GrReducedClip::ElementList&,
+GrDrawState::AutoRestoreEffects*,
+const SkVector& clipOffset,
+const SkRect* devBounds);
+// Draws the clip into the stencil buffer
+bool createStencilClipMask(int32_t elementsGenID,
+GrReducedClip::InitialState initialState,
+const GrReducedClip::ElementList& elements,
+const SkIRect& clipSpaceIBounds,
+const SkIPoint& clipSpaceToStencilOffset);
+// Creates an alpha mask of the clip. The mask is a rasterization of elements through the
+// rect specified by clipSpaceIBounds.
+GrTexture* createAlphaClipMask(int32_t elementsGenID,
+GrReducedClip::InitialState initialState,
+const GrReducedClip::ElementList& elements,
+const SkIRect& clipSpaceIBounds);
+// Similar to createAlphaClipMask but it rasterizes in SW and uploads to the result texture.
+GrTexture* createSoftwareClipMask(int32_t elementsGenID,
+GrReducedClip::InitialState initialState,
+const GrReducedClip::ElementList& elements,
+const SkIRect& clipSpaceIBounds);
+// Gets a texture to use for the clip mask. If true is returned then a cached mask was found
+// that already contains the rasterization of the clip stack, otherwise an uninitialized texture
+// is returned. 'willUpload' is set when the alpha mask needs to be uploaded from the CPU.
+bool getMaskTexture(int32_t elementsGenID,
+const SkIRect& clipSpaceIBounds,
+GrTexture** result,
+bool willUpload);
+bool useSWOnlyPath(const GrReducedClip::ElementList& elements);
+// Draws a clip element into the target alpha mask. The caller should have already setup the
+// desired blend operation. Optionally if the caller already selected a path renderer it can
+// be passed. Otherwise the function will select one if the element is a path.
+bool drawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer* = NULL);
+// Determines whether it is possible to draw the element to both the stencil buffer and the
+// alpha mask simultaneously. If so and the element is a path a compatible path renderer is
+// also returned.
+bool canStencilAndDrawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer**);
+void mergeMask(GrTexture* dstMask,
+GrTexture* srcMask,
+SkRegion::Op op,
+const SkIRect& dstBound,
+const SkIRect& srcBound);
+void getTemp(int width, int height, GrAutoScratchTexture* temp);
+void setupCache(const SkClipStack& clip,
+const SkIRect& bounds);
+/**
+* Called prior to return control back the GrGpu in setupClipping. It
+* updates the GrGpu with stencil settings that account stencil-based
+* clipping.
+*/
+void setGpuStencil();
+/**
+* Adjusts the stencil settings to account for interaction with stencil
+* clipping.
+*/
+void adjustStencilParams(GrStencilSettings* settings,
+StencilClipMode mode,
+int stencilBitCnt);
+typedef SkNoncopyable INHERITED;
+};
+#endif // GrClipMaskManager_DEFINED

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comparison: gfx/skia/trunk/src/gpu/GrClipMaskManager.h

gfx/skia/trunk/src/gpu/GrClipMaskManager.h