1/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkPathEffect_DEFINED
9#define SkPathEffect_DEFINED
10
11#include "include/core/SkFlattenable.h"
12#include "include/core/SkScalar.h"
13// not needed, but some of our clients need it (they don't IWYU)
14#include "include/core/SkPath.h"
15
16class SkPath;
17struct SkRect;
18class SkStrokeRec;
19
20/** \class SkPathEffect
21
22    SkPathEffect is the base class for objects in the SkPaint that affect
23    the geometry of a drawing primitive before it is transformed by the
24    canvas' matrix and drawn.
25
26    Dashing is implemented as a subclass of SkPathEffect.
27*/
28class SK_API SkPathEffect : public SkFlattenable {
29public:
30    /**
31     *  Returns a patheffect that apples each effect (first and second) to the original path,
32     *  and returns a path with the sum of these.
33     *
34     *  result = first(path) + second(path)
35     *
36     */
37    static sk_sp<SkPathEffect> MakeSum(sk_sp<SkPathEffect> first, sk_sp<SkPathEffect> second);
38
39    /**
40     *  Returns a patheffect that applies the inner effect to the path, and then applies the
41     *  outer effect to the result of the inner's.
42     *
43     *  result = outer(inner(path))
44     */
45    static sk_sp<SkPathEffect> MakeCompose(sk_sp<SkPathEffect> outer, sk_sp<SkPathEffect> inner);
46
47    static SkFlattenable::Type GetFlattenableType() {
48        return kSkPathEffect_Type;
49    }
50
51    // move to base?
52
53    enum DashType {
54        kNone_DashType, //!< ignores the info parameter
55        kDash_DashType, //!< fills in all of the info parameter
56    };
57
58    struct DashInfo {
59        DashInfo() : fIntervals(nullptr), fCount(0), fPhase(0) {}
60        DashInfo(SkScalar* intervals, int32_t count, SkScalar phase)
61            : fIntervals(intervals), fCount(count), fPhase(phase) {}
62
63        SkScalar*   fIntervals;         //!< Length of on/off intervals for dashed lines
64                                        //   Even values represent ons, and odds offs
65        int32_t     fCount;             //!< Number of intervals in the dash. Should be even number
66        SkScalar    fPhase;             //!< Offset into the dashed interval pattern
67                                        //   mod the sum of all intervals
68    };
69
70    DashType asADash(DashInfo* info) const;
71
72    /**
73     *  Given a src path (input) and a stroke-rec (input and output), apply
74     *  this effect to the src path, returning the new path in dst, and return
75     *  true. If this effect cannot be applied, return false and ignore dst
76     *  and stroke-rec.
77     *
78     *  The stroke-rec specifies the initial request for stroking (if any).
79     *  The effect can treat this as input only, or it can choose to change
80     *  the rec as well. For example, the effect can decide to change the
81     *  stroke's width or join, or the effect can change the rec from stroke
82     *  to fill (or fill to stroke) in addition to returning a new (dst) path.
83     *
84     *  If this method returns true, the caller will apply (as needed) the
85     *  resulting stroke-rec to dst and then draw.
86     */
87    bool filterPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect* cullR) const;
88
89    /** Version of filterPath that can be called when the CTM is known. */
90    bool filterPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect* cullR,
91                    const SkMatrix& ctm) const;
92
93    /** True if this path effect requires a valid CTM */
94    bool needsCTM() const;
95
96    static sk_sp<SkPathEffect> Deserialize(const void* data, size_t size,
97                                           const SkDeserialProcs* procs = nullptr);
98
99private:
100    SkPathEffect() = default;
101    friend class SkPathEffectBase;
102
103    using INHERITED = SkFlattenable;
104};
105
106#endif
107