1 // Copyright (C) 2013 Google Inc. All rights reserved.
2 //
3 // Redistribution and use in source and binary forms, with or without
4 // modification, are permitted provided that the following conditions are
5 // met:
6 //
7 // * Redistributions of source code must retain the above copyright
8 // notice, this list of conditions and the following disclaimer.
9 // * Redistributions in binary form must reproduce the above
10 // copyright notice, this list of conditions and the following disclaimer
11 // in the documentation and/or other materials provided with the
12 // distribution.
13 // * Neither the name of Google Inc. nor the names of its
14 // contributors may be used to endorse or promote products derived from
15 // this software without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 #include "config.h"
30 #include "platform/graphics/StrokeData.h"
31 #include "wtf/OwnPtr.h"
32 #include "wtf/PassOwnPtr.h"
33
34 namespace WebCore {
35
36 static const int dashRatio = 3; // Ratio of the length of a dash to its width.
37
setLineDash(const DashArray & dashes,float dashOffset)38 void StrokeData::setLineDash(const DashArray& dashes, float dashOffset)
39 {
40 // FIXME: This is lifted directly off SkiaSupport, lines 49-74
41 // so it is not guaranteed to work correctly.
42 size_t dashLength = dashes.size();
43 if (!dashLength) {
44 // If no dash is set, revert to solid stroke
45 // FIXME: do we need to set NoStroke in some cases?
46 m_style = SolidStroke;
47 m_dash.clear();
48 return;
49 }
50
51 size_t count = !(dashLength % 2) ? dashLength : dashLength * 2;
52 OwnPtr<SkScalar[]> intervals = adoptArrayPtr(new SkScalar[count]);
53
54 for (unsigned i = 0; i < count; i++)
55 intervals[i] = dashes[i % dashLength];
56
57 m_dash = adoptRef(SkDashPathEffect::Create(intervals.get(), count, dashOffset));
58 }
59
setupPaint(SkPaint * paint,int length) const60 void StrokeData::setupPaint(SkPaint* paint, int length) const
61 {
62 paint->setStyle(SkPaint::kStroke_Style);
63 paint->setStrokeWidth(SkFloatToScalar(m_thickness));
64 paint->setStrokeCap(m_lineCap);
65 paint->setStrokeJoin(m_lineJoin);
66 paint->setStrokeMiter(SkFloatToScalar(m_miterLimit));
67
68 setupPaintDashPathEffect(paint, length);
69 }
70
setupPaintDashPathEffect(SkPaint * paint,int length) const71 void StrokeData::setupPaintDashPathEffect(SkPaint* paint, int length) const
72 {
73 float width = m_thickness;
74 if (m_dash) {
75 paint->setPathEffect(m_dash.get());
76 } else {
77 switch (m_style) {
78 case NoStroke:
79 case SolidStroke:
80 case DoubleStroke:
81 case WavyStroke: // FIXME: https://code.google.com/p/chromium/issues/detail?id=229574
82 paint->setPathEffect(0);
83 return;
84 case DashedStroke:
85 width = dashRatio * width;
86 // Fall through.
87 case DottedStroke:
88 // Truncate the width, since we don't want fuzzy dots or dashes.
89 int dashLength = static_cast<int>(width);
90 // Subtract off the endcaps, since they're rendered separately.
91 int distance = length - 2 * static_cast<int>(m_thickness);
92 int phase = 1;
93 if (dashLength > 1) {
94 // Determine how many dashes or dots we should have.
95 int numDashes = distance / dashLength;
96 int remainder = distance % dashLength;
97 // Adjust the phase to center the dashes within the line.
98 if (numDashes % 2) {
99 // Odd: shift right a full dash, minus half the remainder.
100 phase = dashLength - remainder / 2;
101 } else {
102 // Even: shift right half a dash, minus half the remainder.
103 phase = (dashLength - remainder) / 2;
104 }
105 }
106 SkScalar dashLengthSk = SkIntToScalar(dashLength);
107 SkScalar intervals[2] = { dashLengthSk, dashLengthSk };
108 RefPtr<SkDashPathEffect> pathEffect = adoptRef(SkDashPathEffect::Create(intervals, 2, SkIntToScalar(phase)));
109 paint->setPathEffect(pathEffect.get());
110 }
111 }
112 }
113
114 } // namespace
115