OLD | NEW |
---|---|
(Empty) | |
1 /* | |
2 * Copyright (C) 2015 Google Inc. All rights reserved. | |
3 * | |
4 * Redistribution and use in source and binary forms, with or without | |
5 * modification, are permitted provided that the following conditions | |
6 * are met: | |
7 * 1. Redistributions of source code must retain the above copyright | |
8 * notice, this list of conditions and the following disclaimer. | |
9 * 2. Redistributions in binary form must reproduce the above copyright | |
10 * notice, this list of conditions and the following disclaimer in the | |
11 * documentation and/or other materials provided with the distribution. | |
12 * | |
13 * THIS SOFTWARE IS PROVIDED BY GOOGLE INC. ``AS IS'' AND ANY | |
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR | |
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | |
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
24 */ | |
25 | |
26 #ifndef CachingWordShapeIterator_h | |
27 #define CachingWordShapeIterator_h | |
28 | |
29 #include "platform/fonts/SimpleFontData.h" | |
30 #include "platform/fonts/shaping/CachingWordShapeIterator.h" | |
31 #include "platform/fonts/shaping/HarfBuzzShaper.h" | |
32 #include "platform/fonts/shaping/ShapeCache.h" | |
33 #include "wtf/unicode/CharacterNames.h" | |
34 | |
35 namespace blink { | |
36 | |
37 class CachingWordShapeIterator { | |
38 public: | |
39 CachingWordShapeIterator(ShapeCache* cache, const TextRun& run, | |
40 const Font* font, HashSet<const SimpleFontData*>* fallbackFonts) | |
41 : m_shapeCache(cache), m_textRun(run), m_font(font) | |
42 , m_fallbackFonts(fallbackFonts), m_startIndex(0) | |
43 { | |
44 ASSERT(font); | |
45 const FontDescription& fontDescription = font->fontDescription(); | |
46 bool hasWordSpacingOrLetterSpacing = fontDescription.wordSpacing() | |
47 || fontDescription.letterSpacing(); | |
48 // Word spacing and letter spacing can change the width of a word. | |
49 // If a tab occurs inside a word, the width of the word varies based on | |
50 // its position on the line. | |
51 // If expansion is used (for justified text) the spacing between words | |
52 // change and thus we cannot use the word cache. | |
53 // FIXME: Move expansion handling from shaping to ShapeResult and add | |
54 // support for expansion to shapeWord. | |
55 m_isCacheable = !hasWordSpacingOrLetterSpacing && !run.allowTabs() | |
56 && m_textRun.expansion() == 0.0f; | |
57 | |
58 // Shaping word by word is faster as each word is cached. If we cannot | |
59 // use the cache or if the font doesn't support word by word shaping | |
60 // fall back on shaping the entire run. | |
61 m_shapeByWord = m_font->canShapeWordByWord() && m_isCacheable; | |
62 } | |
63 | |
64 bool next(RefPtr<ShapeResult>* wordResult) | |
65 { | |
66 if (!m_shapeByWord) { | |
67 if (m_startIndex) | |
68 return false; | |
69 *wordResult = shapeWord(m_textRun, m_font, m_fallbackFonts); | |
70 m_startIndex = 1; | |
71 return *wordResult; | |
72 } | |
73 | |
74 unsigned length = m_textRun.length(); | |
75 if (m_startIndex < length) { | |
76 if (m_textRun[m_startIndex] == spaceCharacter) { | |
77 if (!m_spaceShape) { | |
78 TextRun wordRun = m_textRun.subRun(m_startIndex, 1); | |
79 m_spaceShape = shapeWord(wordRun, m_font, m_fallbackFonts); | |
80 } | |
81 *wordResult = m_spaceShape; | |
82 m_startIndex++; | |
83 return true; | |
84 } | |
85 | |
86 for (unsigned i = m_startIndex; ; i++) { | |
87 if (i == length || m_textRun[i] == spaceCharacter) { | |
88 TextRun wordRun = m_textRun.subRun(m_startIndex, | |
89 i - m_startIndex); | |
90 *wordResult = shapeWord(wordRun, m_font, m_fallbackFonts); | |
91 m_startIndex = i; | |
92 return true; | |
93 } | |
94 } | |
95 } | |
96 return false; | |
97 } | |
98 | |
99 private: | |
100 PassRefPtr<ShapeResult> shapeWord(const TextRun& wordRun, | |
101 const Font* font, HashSet<const SimpleFontData*>* fallbackFonts) | |
102 { | |
103 ShapeCacheEntry* cacheEntry = m_isCacheable | |
104 ? m_shapeCache->add(wordRun, ShapeCacheEntry()) | |
105 : nullptr; | |
106 if (cacheEntry && cacheEntry->m_shapeResult) | |
107 return cacheEntry->m_shapeResult; | |
108 | |
109 HarfBuzzShaper shaper(font, wordRun, fallbackFonts); | |
110 RefPtr<ShapeResult> shapeResult = shaper.shapeResult(); | |
111 if (!shapeResult) | |
112 return nullptr; | |
113 | |
114 if (cacheEntry && (!fallbackFonts || fallbackFonts->isEmpty())) | |
drott
2015/06/23 12:45:51
Could you add a similar FIXME + crbug for the fact
| |
115 cacheEntry->m_shapeResult = shapeResult; | |
116 | |
117 return shapeResult.release(); | |
118 } | |
119 | |
120 ShapeCache* m_shapeCache; | |
121 const TextRun& m_textRun; | |
122 const Font* m_font; | |
123 HashSet<const SimpleFontData*>* m_fallbackFonts; | |
124 unsigned m_startIndex : 30; | |
125 unsigned m_isCacheable : 1; | |
drott
2015/06/23 12:45:51
When reviewing, I struggled to understand what thi
| |
126 unsigned m_shapeByWord : 1; | |
127 RefPtr<ShapeResult> m_spaceShape; | |
128 }; | |
129 | |
130 } // namespace blink | |
131 | |
132 #endif // CachingWordShapeIterator_h | |
OLD | NEW |