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* Copyright 2016 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef GrStyle_DEFINED
#define GrStyle_DEFINED
#include "include/core/SkPathEffect.h"
#include "include/core/SkStrokeRec.h"
#include "include/gpu/GrTypes.h"
#include "include/private/SkTemplates.h"
* Represents the various ways that a GrShape can be styled. It has fill/stroking information
* as well as an optional path effect. If the path effect represents dashing, the dashing
* information is extracted from the path effect and stored explicitly.
* This will replace GrStrokeInfo as GrShape is deployed.
class GrStyle {
* A style object that represents a fill with no path effect.
* TODO: constexpr with C++14
static const GrStyle& SimpleFill() {
static const GrStyle kFill(SkStrokeRec::kFill_InitStyle);
return kFill;
* A style object that represents a hairline stroke with no path effect.
* TODO: constexpr with C++14
static const GrStyle& SimpleHairline() {
static const GrStyle kHairline(SkStrokeRec::kHairline_InitStyle);
return kHairline;
enum class Apply {
* Optional flags for computing keys that may remove unnecessary variation in the key due to
* style settings that don't affect particular classes of geometry.
enum KeyFlags {
// The shape being styled has no open contours.
kClosed_KeyFlag = 0x1,
// The shape being styled doesn't have any joins and so isn't affected by join type.
kNoJoins_KeyFlag = 0x2
* Computes the key length for a GrStyle. The return will be negative if it cannot be turned
* into a key. This occurs when there is a path effect that is not a dash. The key can
* either reflect just the path effect (if one) or the path effect and the strokerec. Note
* that a simple fill has a zero sized key.
static int KeySize(const GrStyle&, Apply, uint32_t flags = 0);
* Writes a unique key for the style into the provided buffer. This function assumes the buffer
* has room for at least KeySize() values. It assumes that KeySize() returns a non-negative
* value for the combination of GrStyle, Apply and flags params. This is written so that the key
* for just dash application followed by the key for the remaining SkStrokeRec is the same as
* the key for applying dashing and SkStrokeRec all at once.
static void WriteKey(uint32_t*, const GrStyle&, Apply, SkScalar scale, uint32_t flags = 0);
GrStyle() : GrStyle(SkStrokeRec::kFill_InitStyle) {}
explicit GrStyle(SkStrokeRec::InitStyle initStyle) : fStrokeRec(initStyle) {}
GrStyle(const SkStrokeRec& strokeRec, sk_sp<SkPathEffect> pe) : fStrokeRec(strokeRec) {
GrStyle(const GrStyle& that) = default;
explicit GrStyle(const SkPaint& paint) : fStrokeRec(paint) {
explicit GrStyle(const SkPaint& paint, SkPaint::Style overrideStyle)
: fStrokeRec(paint, overrideStyle) {
GrStyle& operator=(const GrStyle& that) {
fPathEffect = that.fPathEffect;
fDashInfo = that.fDashInfo;
fStrokeRec = that.fStrokeRec;
return *this;
void resetToInitStyle(SkStrokeRec::InitStyle fillOrHairline) {
if (SkStrokeRec::kFill_InitStyle == fillOrHairline) {
} else {
/** Is this style a fill with no path effect? */
bool isSimpleFill() const { return fStrokeRec.isFillStyle() && !fPathEffect; }
/** Is this style a hairline with no path effect? */
bool isSimpleHairline() const { return fStrokeRec.isHairlineStyle() && !fPathEffect; }
SkPathEffect* pathEffect() const { return fPathEffect.get(); }
sk_sp<SkPathEffect> refPathEffect() const { return fPathEffect; }
bool hasPathEffect() const { return SkToBool(fPathEffect.get()); }
bool hasNonDashPathEffect() const { return fPathEffect.get() && !this->isDashed(); }
bool isDashed() const { return SkPathEffect::kDash_DashType == fDashInfo.fType; }
SkScalar dashPhase() const {
return fDashInfo.fPhase;
int dashIntervalCnt() const {
return fDashInfo.fIntervals.count();
const SkScalar* dashIntervals() const {
return fDashInfo.fIntervals.get();
const SkStrokeRec& strokeRec() const { return fStrokeRec; }
/** Hairline or fill styles without path effects make no alterations to a geometry. */
bool applies() const {
return this->pathEffect() || (!fStrokeRec.isFillStyle() && !fStrokeRec.isHairlineStyle());
static SkScalar MatrixToScaleFactor(const SkMatrix& matrix) {
// getMaxScale will return -1 if the matrix has perspective. In that case we can use a scale
// factor of 1. This isn't necessarily a good choice and in the future we might consider
// taking a bounds here for the perspective case.
return SkScalarAbs(matrix.getMaxScale());
* Applies just the path effect and returns remaining stroke information. This will fail if
* there is no path effect. dst may or may not have been overwritten on failure. Scale controls
* geometric approximations made by the path effect. It is typically computed from the view
* matrix.
bool SK_WARN_UNUSED_RESULT applyPathEffectToPath(SkPath* dst, SkStrokeRec* remainingStoke,
const SkPath& src, SkScalar scale) const;
* If this succeeds then the result path should be filled or hairlined as indicated by the
* returned SkStrokeRec::InitStyle value. Will fail if there is no path effect and the
* strokerec doesn't change the geometry. When this fails the outputs may or may not have
* been overwritten. Scale controls geometric approximations made by the path effect and
* stroker. It is typically computed from the view matrix.
bool SK_WARN_UNUSED_RESULT applyToPath(SkPath* dst, SkStrokeRec::InitStyle* fillOrHairline,
const SkPath& src, SkScalar scale) const;
/** Given bounds of a path compute the bounds of path with the style applied. */
void adjustBounds(SkRect* dst, const SkRect& src) const {
if (this->pathEffect()) {
this->pathEffect()->computeFastBounds(dst, src);
// This may not be the correct SkStrokeRec to use.
// It happens to work for dashing.
SkScalar radius = fStrokeRec.getInflationRadius();
dst->outset(radius, radius);
} else {
SkScalar radius = fStrokeRec.getInflationRadius();
*dst = src.makeOutset(radius, radius);
void initPathEffect(sk_sp<SkPathEffect> pe);
struct DashInfo {
DashInfo() : fType(SkPathEffect::kNone_DashType) {}
DashInfo(const DashInfo& that) { *this = that; }
DashInfo& operator=(const DashInfo& that) {
fType = that.fType;
fPhase = that.fPhase;
sk_careful_memcpy(fIntervals.get(), that.fIntervals.get(),
sizeof(SkScalar) * that.fIntervals.count());
return *this;
void reset() {
fType = SkPathEffect::kNone_DashType;
SkPathEffect::DashType fType;
SkScalar fPhase;
SkAutoSTArray<4, SkScalar> fIntervals;
bool applyPathEffect(SkPath* dst, SkStrokeRec* strokeRec, const SkPath& src) const;
SkStrokeRec fStrokeRec;
sk_sp<SkPathEffect> fPathEffect;
DashInfo fDashInfo;