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* Copyright 2014 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef GrPathRendering_DEFINED
#define GrPathRendering_DEFINED
#include "SkPath.h"
#include "GrGpu.h"
#include "GrPathRange.h"
class SkDescriptor;
class SkTypeface;
class GrPath;
class GrStencilSettings;
class GrStrokeInfo;
* Abstract class wrapping HW path rendering API.
* The subclasses of this class use the possible HW API to render paths (as opposed to path
* rendering implemented in Skia on top of a "3d" HW API).
* The subclasses hold the global state needed to render paths, including shadow of the global HW
* API state. Similar to GrGpu.
* It is expected that the lifetimes of GrGpuXX and GrXXPathRendering are the same. The call context
* interface (eg. * the concrete instance of GrGpu subclass) should be provided to the instance
* during construction.
class GrPathRendering {
virtual ~GrPathRendering() { }
typedef GrPathRange::PathIndexType PathIndexType;
enum PathTransformType {
kNone_PathTransformType, //!< []
kTranslateX_PathTransformType, //!< [kMTransX]
kTranslateY_PathTransformType, //!< [kMTransY]
kTranslate_PathTransformType, //!< [kMTransX, kMTransY]
kAffine_PathTransformType, //!< [kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY]
kLast_PathTransformType = kAffine_PathTransformType
static inline int PathTransformSize(PathTransformType type) {
switch (type) {
case kNone_PathTransformType:
return 0;
case kTranslateX_PathTransformType:
case kTranslateY_PathTransformType:
return 1;
case kTranslate_PathTransformType:
return 2;
case kAffine_PathTransformType:
return 6;
SkFAIL("Unknown path transform type");
return 0;
// No native support for inverse at this time
enum FillType {
/** Specifies that "inside" is computed by a non-zero sum of signed
edge crossings
/** Specifies that "inside" is computed by an odd number of edge
* Creates a new gpu path, based on the specified path and stroke and returns it.
* The caller owns a ref on the returned path which must be balanced by a call to unref.
* @param skPath the path geometry.
* @param stroke the path stroke.
* @return a new path.
virtual GrPath* createPath(const SkPath&, const GrStrokeInfo&) = 0;
* Creates a range of gpu paths with a common stroke. The caller owns a ref on the
* returned path range which must be balanced by a call to unref.
* @param PathGenerator class that generates SkPath objects for each path in the range.
* @param GrStrokeInfo the common stroke applied to each path in the range.
* @return a new path range.
virtual GrPathRange* createPathRange(GrPathRange::PathGenerator*, const GrStrokeInfo&) = 0;
* Creates a range of glyph paths, indexed by glyph id. The glyphs will have an
* inverted y-direction in order to match the raw font path data. The caller owns
* a ref on the returned path range which must be balanced by a call to unref.
* @param SkTypeface Typeface that defines the glyphs.
* If null, the default typeface will be used.
* @param SkDescriptor Additional font configuration that specifies the font's size,
* stroke, and other flags. This will generally come from an
* SkGlyphCache.
* It is recommended to leave this value null when possible, in
* which case the glyphs will be loaded directly from the font's
* raw path data and sized at SkPaint::kCanonicalTextSizeForPaths.
* This will result in less memory usage and more efficient paths.
* If non-null, the glyph paths will match the font descriptor,
* including with the stroke information baked directly into
* the outlines.
* @param GrStrokeInfo Common stroke that the GPU will apply to every path. Note that
* if the glyph outlines contain baked-in strokes from the font
* descriptor, the GPU stroke will be applied on top of those
* outlines.
* @return a new path range populated with glyphs.
virtual GrPathRange* createGlyphs(const SkTypeface*, const SkDescriptor*,
const GrStrokeInfo&) = 0;
/** None of these params are optional, pointers used just to avoid making copies. */
struct StencilPathArgs {
StencilPathArgs(bool useHWAA,
GrRenderTarget* renderTarget,
const SkMatrix* viewMatrix,
const GrScissorState* scissor,
const GrStencilSettings* stencil)
: fUseHWAA(useHWAA)
, fRenderTarget(renderTarget)
, fViewMatrix(viewMatrix)
, fScissor(scissor)
, fStencil(stencil) {
bool fUseHWAA;
GrRenderTarget* fRenderTarget;
const SkMatrix* fViewMatrix;
const GrScissorState* fScissor;
const GrStencilSettings* fStencil;
void stencilPath(const StencilPathArgs& args, const GrPath* path) {
this->onStencilPath(args, path);
struct DrawPathArgs : public GrGpu::DrawArgs {
DrawPathArgs(const GrPrimitiveProcessor* primProc,
const GrPipeline* pipeline,
const GrProgramDesc* desc,
const GrBatchTracker* batchTracker,
const GrStencilSettings* stencil)
: DrawArgs(primProc, pipeline, desc, batchTracker)
, fStencil(stencil) {
const GrStencilSettings* fStencil;
void drawPath(const DrawPathArgs& args, const GrPath* path) {
this->onDrawPath(args, path);
void drawPaths(const DrawPathArgs& args, const GrPathRange* pathRange, const void* indices,
PathIndexType indexType, const float transformValues[],
PathTransformType transformType, int count) {
pathRange->willDrawPaths(indices, indexType, count);
this->onDrawPaths(args, pathRange, indices, indexType, transformValues, transformType,
GrPathRendering(GrGpu* gpu)
: fGpu(gpu) {
virtual void onStencilPath(const StencilPathArgs&, const GrPath*) = 0;
virtual void onDrawPath(const DrawPathArgs&, const GrPath*) = 0;
virtual void onDrawPaths(const DrawPathArgs&, const GrPathRange*, const void*, PathIndexType,
const float[], PathTransformType, int) = 0;
GrGpu* fGpu;
GrPathRendering& operator=(const GrPathRendering&);