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* Copyright 2006 The Android Open Source Project
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkPathEffect_DEFINED
#define SkPathEffect_DEFINED
#include "include/core/SkFlattenable.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/private/base/SkAPI.h"
// TODO(kjlubick) update clients and remove this unnecessary #include
#include "include/core/SkPath.h" // IWYU pragma: keep
#include <cstddef>
#include <cstdint>
class SkMatrix;
class SkStrokeRec;
struct SkDeserialProcs;
struct SkRect;
/** \class SkPathEffect
SkPathEffect is the base class for objects in the SkPaint that affect
the geometry of a drawing primitive before it is transformed by the
canvas' matrix and drawn.
Dashing is implemented as a subclass of SkPathEffect.
class SK_API SkPathEffect : public SkFlattenable {
* Returns a patheffect that apples each effect (first and second) to the original path,
* and returns a path with the sum of these.
* result = first(path) + second(path)
static sk_sp<SkPathEffect> MakeSum(sk_sp<SkPathEffect> first, sk_sp<SkPathEffect> second);
* Returns a patheffect that applies the inner effect to the path, and then applies the
* outer effect to the result of the inner's.
* result = outer(inner(path))
static sk_sp<SkPathEffect> MakeCompose(sk_sp<SkPathEffect> outer, sk_sp<SkPathEffect> inner);
static SkFlattenable::Type GetFlattenableType() {
return kSkPathEffect_Type;
// move to base?
enum DashType {
kNone_DashType, //!< ignores the info parameter
kDash_DashType, //!< fills in all of the info parameter
struct DashInfo {
DashInfo() : fIntervals(nullptr), fCount(0), fPhase(0) {}
DashInfo(SkScalar* intervals, int32_t count, SkScalar phase)
: fIntervals(intervals), fCount(count), fPhase(phase) {}
SkScalar* fIntervals; //!< Length of on/off intervals for dashed lines
// Even values represent ons, and odds offs
int32_t fCount; //!< Number of intervals in the dash. Should be even number
SkScalar fPhase; //!< Offset into the dashed interval pattern
// mod the sum of all intervals
DashType asADash(DashInfo* info) const;
* Given a src path (input) and a stroke-rec (input and output), apply
* this effect to the src path, returning the new path in dst, and return
* true. If this effect cannot be applied, return false and ignore dst
* and stroke-rec.
* The stroke-rec specifies the initial request for stroking (if any).
* The effect can treat this as input only, or it can choose to change
* the rec as well. For example, the effect can decide to change the
* stroke's width or join, or the effect can change the rec from stroke
* to fill (or fill to stroke) in addition to returning a new (dst) path.
* If this method returns true, the caller will apply (as needed) the
* resulting stroke-rec to dst and then draw.
bool filterPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect* cullR) const;
/** Version of filterPath that can be called when the CTM is known. */
bool filterPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect* cullR,
const SkMatrix& ctm) const;
/** True if this path effect requires a valid CTM */
bool needsCTM() const;
static sk_sp<SkPathEffect> Deserialize(const void* data, size_t size,
const SkDeserialProcs* procs = nullptr);
SkPathEffect() = default;
friend class SkPathEffectBase;
using INHERITED = SkFlattenable;