aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/effects/SkCornerPathEffect.cpp
blob: 06558826bf5d4f3a921e7984a82c5b218aba26a7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143

/*
 * 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.
 */


#include "SkCornerPathEffect.h"
#include "SkPath.h"
#include "SkPoint.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"

SkCornerPathEffect::SkCornerPathEffect(SkScalar radius) : fRadius(radius) {}
SkCornerPathEffect::~SkCornerPathEffect() {}

static bool ComputeStep(const SkPoint& a, const SkPoint& b, SkScalar radius,
                        SkPoint* step) {
    SkScalar dist = SkPoint::Distance(a, b);

    step->set(b.fX - a.fX, b.fY - a.fY);

    if (dist <= radius * 2) {
        step->scale(SK_ScalarHalf);
        return false;
    } else {
        step->scale(SkScalarDiv(radius, dist));
        return true;
    }
}

bool SkCornerPathEffect::filterPath(SkPath* dst, const SkPath& src,
                                    SkStrokeRec*, const SkRect*) const {
    if (0 == fRadius) {
        return false;
    }

    SkPath::Iter    iter(src, false);
    SkPath::Verb    verb, prevVerb = (SkPath::Verb)-1;
    SkPoint         pts[4];

    bool        closed;
    SkPoint     moveTo, lastCorner;
    SkVector    firstStep, step;
    bool        prevIsValid = true;

    // to avoid warnings
    moveTo.set(0, 0);
    firstStep.set(0, 0);
    lastCorner.set(0, 0);

    for (;;) {
        switch (verb = iter.next(pts, false)) {
            case SkPath::kMove_Verb:
                    // close out the previous (open) contour
                if (SkPath::kLine_Verb == prevVerb) {
                    dst->lineTo(lastCorner);
                }
                closed = iter.isClosedContour();
                if (closed) {
                    moveTo = pts[0];
                    prevIsValid = false;
                } else {
                    dst->moveTo(pts[0]);
                    prevIsValid = true;
                }
                break;
            case SkPath::kLine_Verb: {
                bool drawSegment = ComputeStep(pts[0], pts[1], fRadius, &step);
                // prev corner
                if (!prevIsValid) {
                    dst->moveTo(moveTo + step);
                    prevIsValid = true;
                } else {
                    dst->quadTo(pts[0].fX, pts[0].fY, pts[0].fX + step.fX,
                                pts[0].fY + step.fY);
                }
                if (drawSegment) {
                    dst->lineTo(pts[1].fX - step.fX, pts[1].fY - step.fY);
                }
                lastCorner = pts[1];
                prevIsValid = true;
                break;
            }
            case SkPath::kQuad_Verb:
                // TBD - just replicate the curve for now
                if (!prevIsValid) {
                    dst->moveTo(pts[0]);
                    prevIsValid = true;
                }
                dst->quadTo(pts[1], pts[2]);
                lastCorner = pts[2];
                firstStep.set(0, 0);
                break;
            case SkPath::kCubic_Verb:
                if (!prevIsValid) {
                    dst->moveTo(pts[0]);
                    prevIsValid = true;
                }
                // TBD - just replicate the curve for now
                dst->cubicTo(pts[1], pts[2], pts[3]);
                lastCorner = pts[3];
                firstStep.set(0, 0);
                break;
            case SkPath::kClose_Verb:
                if (firstStep.fX || firstStep.fY) {
                    dst->quadTo(lastCorner.fX, lastCorner.fY,
                                lastCorner.fX + firstStep.fX,
                                lastCorner.fY + firstStep.fY);
                    }
                dst->close();
                break;
            case SkPath::kConic_Verb:
                SkASSERT(0);
                break;
            case SkPath::kDone_Verb:
                goto DONE;
        }

        if (SkPath::kMove_Verb == prevVerb) {
            firstStep = step;
        }
        prevVerb = verb;
    }
DONE:
    return true;
}

SkFlattenable* SkCornerPathEffect::CreateProc(SkReadBuffer& buffer) {
    return SkCornerPathEffect::Create(buffer.readScalar());
}

void SkCornerPathEffect::flatten(SkWriteBuffer& buffer) const {
    buffer.writeScalar(fRadius);
}

#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
SkCornerPathEffect::SkCornerPathEffect(SkReadBuffer& buffer) {
    fRadius = buffer.readScalar();
}
#endif