The Tor Browser: gfx/skia/trunk/src/gpu/GrPathRenderer.h@6474c204b198 (annotated)

gfx/skia/trunk/src/gpu/GrPathRenderer.h@6474c204b198 (annotated)

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

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * 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 "GrDrawTarget.h"
 #include "GrPathRendererChain.h"
 #include "GrStencil.h"
 #include "SkDrawProcs.h"
 #include "SkStrokeRec.h"
 #include "SkTArray.h"
 class SkPath;
 struct GrPoint;
 /**
  *  Base class for drawing paths into a GrDrawTarget.
  *
  *  Derived classes can use stages GrPaint::kTotalStages through GrDrawState::kNumStages-1. The
  *  stages before GrPaint::kTotalStages are reserved for setting up the draw (i.e., textures and
  *  filter masks).
  */
 class SK_API GrPathRenderer : public SkRefCnt {
 public:
     SK_DECLARE_INST_COUNT(GrPathRenderer)
     /**
      * This is called to install custom path renderers in every GrContext at create time. The
      * default implementation in GrCreatePathRenderer_none.cpp does not add any additional
      * renderers. Link against another implementation to install your own. The first added is the
      * most preferred path renderer, second is second most preferred, etc.
      *
      * @param context   the context that will use the path renderer
      * @param prChain   the chain to add path renderers to.
      */
     static void AddPathRenderers(GrContext* context, GrPathRendererChain* prChain);
     GrPathRenderer();
     /**
      * 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 GrEffect 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 sets up the GrDrawState on the target
      *                    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.
      */
     typedef GrPathRendererChain::StencilSupport StencilSupport;
     static const StencilSupport kNoSupport_StencilSupport =
         GrPathRendererChain::kNoSupport_StencilSupport;
     static const StencilSupport kStencilOnly_StencilSupport =
         GrPathRendererChain::kStencilOnly_StencilSupport;
     static const StencilSupport kNoRestriction_StencilSupport =
         GrPathRendererChain::kNoRestriction_StencilSupport;
     /**
      * This function is to get the stencil support for a particular path. The path's fill must
      * not be an inverse type.
      *
      * @param target    target that the path will be rendered to
      * @param path      the path that will be drawn
      * @param stroke    the stroke information (width, join, cap).
      */
     StencilSupport getStencilSupport(const SkPath& path,
                                      const SkStrokeRec& stroke,
                                      const GrDrawTarget* target) const {
         SkASSERT(!path.isInverseFillType());
         return this->onGetStencilSupport(path, stroke, target);
     }
     /**
      * Returns true if this path renderer is able to render the path. Returning false allows the
      * caller to fallback to another path renderer This function is called when searching for a path
      * renderer capable of rendering a path.
      *
      * @param path       The path to draw
      * @param stroke     The stroke information (width, join, cap)
      * @param target     The target that the path will be rendered to
      * @param antiAlias  True if anti-aliasing is required.
      *
      * @return  true if the path can be drawn by this object, false otherwise.
      */
     virtual bool canDrawPath(const SkPath& path,
                              const SkStrokeRec& rec,
                              const GrDrawTarget* target,
                              bool antiAlias) const = 0;
     /**
      * Draws the path into the draw target. If getStencilSupport() would return kNoRestriction then
      * the subclass must respect the stencil settings of the target's draw state.
      *
      * @param path                  the path to draw.
      * @param stroke                the stroke information (width, join, cap)
      * @param target                target that the path will be rendered to
      * @param antiAlias             true if anti-aliasing is required.
      */
     bool drawPath(const SkPath& path,
                   const SkStrokeRec& stroke,
                   GrDrawTarget* target,
                   bool antiAlias) {
         SkASSERT(!path.isEmpty());
         SkASSERT(this->canDrawPath(path, stroke, target, antiAlias));
         SkASSERT(target->drawState()->getStencil().isDisabled() ||
                  kNoRestriction_StencilSupport == this->getStencilSupport(path, stroke, target));
         return this->onDrawPath(path, stroke, target, antiAlias);
     }
     /**
      * 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.
      *
      * @param path                  the path to draw.
      * @param stroke                the stroke information (width, join, cap)
      * @param target                target that the path will be rendered to
      */
     void stencilPath(const SkPath& path, const SkStrokeRec& stroke, GrDrawTarget* target) {
         SkASSERT(!path.isEmpty());
         SkASSERT(kNoSupport_StencilSupport != this->getStencilSupport(path, stroke, target));
         this->onStencilPath(path, stroke, target);
     }
     // Helper for determining if we can treat a thin stroke as a hairline w/ coverage.
     // If we can, we draw lots faster (raster device does this same test).
     static bool IsStrokeHairlineOrEquivalent(const SkStrokeRec& stroke, const SkMatrix& matrix,
                                              SkScalar* outCoverage) {
         if (stroke.isHairlineStyle()) {
             if (NULL != outCoverage) {
                 *outCoverage = SK_Scalar1;
             }
             return true;
         }
         return stroke.getStyle() == SkStrokeRec::kStroke_Style &&
             SkDrawTreatAAStrokeAsHairline(stroke.getWidth(), matrix, outCoverage);
     }
 protected:
     /**
      * Subclass overrides if it has any limitations of stenciling support.
      */
     virtual StencilSupport onGetStencilSupport(const SkPath&,
                                                const SkStrokeRec&,
                                                const GrDrawTarget*) const {
         return kNoRestriction_StencilSupport;
     }
     /**
      * Subclass implementation of drawPath()
      */
     virtual bool onDrawPath(const SkPath& path,
                             const SkStrokeRec& stroke,
                             GrDrawTarget* target,
                             bool antiAlias) = 0;
     /**
      * Subclass implementation of stencilPath(). Subclass must override iff it ever returns
      * kStencilOnly in onGetStencilSupport().
      */
     virtual void onStencilPath(const SkPath& path,  const SkStrokeRec& stroke, GrDrawTarget* target) {
         GrDrawTarget::AutoStateRestore asr(target, GrDrawTarget::kPreserve_ASRInit);
         GrDrawState* drawState = target->drawState();
         GR_STATIC_CONST_SAME_STENCIL(kIncrementStencil,
                                      kReplace_StencilOp,
                                      kReplace_StencilOp,
                                      kAlways_StencilFunc,
 xffff,
 xffff,
 xffff);
         drawState->setStencil(kIncrementStencil);
         drawState->enableState(GrDrawState::kNoColorWrites_StateBit);
         this->drawPath(path, stroke, target, false);
     }
     // 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,
                                  int devW,
                                  int devH,
                                  const SkMatrix& matrix,
                                  SkRect* bounds);
     // Helper version that gets the dev width and height from a GrSurface.
     static void GetPathDevBounds(const SkPath& path,
                                  const GrSurface* device,
                                  const SkMatrix& matrix,
                                  SkRect* bounds) {
         GetPathDevBounds(path, device->width(), device->height(), matrix, bounds);
     }
 private:
     typedef SkRefCnt INHERITED;
 };
 #endif

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gfx/skia/trunk/src/gpu/GrPathRenderer.h@6474c204b198 (annotated)

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