1 /*
2 * Copyright (C) 2011 Apple Inc. All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB. If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 *
19 */
20
21 #include "config.h"
22 #include "RenderCombineText.h"
23
24 #include "TextRun.h"
25
26 namespace WebCore {
27
28 const float textCombineMargin = 1.1f; // Allow em + 10% margin
29
RenderCombineText(Node * node,PassRefPtr<StringImpl> string)30 RenderCombineText::RenderCombineText(Node* node, PassRefPtr<StringImpl> string)
31 : RenderText(node, string)
32 , m_combinedTextWidth(0)
33 , m_isCombined(false)
34 , m_needsFontUpdate(false)
35 {
36 }
37
styleDidChange(StyleDifference diff,const RenderStyle * oldStyle)38 void RenderCombineText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
39 {
40 setStyleInternal(RenderStyle::clone(style()));
41 RenderText::styleDidChange(diff, oldStyle);
42
43 if (m_isCombined)
44 RenderText::setTextInternal(originalText()); // This RenderCombineText has been combined once. Restore the original text for the next combineText().
45
46 m_needsFontUpdate = true;
47 }
48
setTextInternal(PassRefPtr<StringImpl> text)49 void RenderCombineText::setTextInternal(PassRefPtr<StringImpl> text)
50 {
51 RenderText::setTextInternal(text);
52
53 m_needsFontUpdate = true;
54 }
55
width(unsigned from,unsigned length,const Font & font,float xPosition,HashSet<const SimpleFontData * > * fallbackFonts,GlyphOverflow * glyphOverflow) const56 float RenderCombineText::width(unsigned from, unsigned length, const Font& font, float xPosition, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
57 {
58 if (!characters())
59 return 0;
60
61 if (m_isCombined)
62 return font.size();
63
64 return RenderText::width(from, length, font, xPosition, fallbackFonts, glyphOverflow);
65 }
66
adjustTextOrigin(FloatPoint & textOrigin,const FloatRect & boxRect) const67 void RenderCombineText::adjustTextOrigin(FloatPoint& textOrigin, const FloatRect& boxRect) const
68 {
69 if (m_isCombined)
70 textOrigin.move(boxRect.height() / 2 - ceilf(m_combinedTextWidth) / 2, style()->font().pixelSize());
71 }
72
charactersToRender(int start,const UChar * & characters,int & length) const73 void RenderCombineText::charactersToRender(int start, const UChar*& characters, int& length) const
74 {
75 if (m_isCombined) {
76 length = originalText()->length();
77 characters = originalText()->characters();
78 return;
79 }
80
81 characters = text()->characters() + start;
82 }
83
combineText()84 void RenderCombineText::combineText()
85 {
86 if (!m_needsFontUpdate)
87 return;
88
89 m_isCombined = false;
90 m_needsFontUpdate = false;
91
92 // CSS3 spec says text-combine works only in vertical writing mode.
93 if (style()->isHorizontalWritingMode())
94 return;
95
96 TextRun run = TextRun(String(text()));
97 FontDescription description = originalFont().fontDescription();
98 float emWidth = description.computedSize() * textCombineMargin;
99 bool shouldUpdateFont = false;
100
101 description.setOrientation(Horizontal); // We are going to draw combined text horizontally.
102 m_combinedTextWidth = originalFont().width(run);
103 m_isCombined = m_combinedTextWidth <= emWidth;
104
105 if (m_isCombined)
106 shouldUpdateFont = style()->setFontDescription(description); // Need to change font orientation to horizontal.
107 else {
108 // Need to try compressed glyphs.
109 static const FontWidthVariant widthVariants[] = { HalfWidth, ThirdWidth, QuarterWidth };
110 for (size_t i = 0 ; i < WTF_ARRAY_LENGTH(widthVariants) ; ++i) {
111 description.setWidthVariant(widthVariants[i]);
112 Font compressedFont = Font(description, style()->font().letterSpacing(), style()->font().wordSpacing());
113 compressedFont.update(style()->font().fontSelector());
114 float runWidth = compressedFont.width(run);
115 if (runWidth <= emWidth) {
116 m_combinedTextWidth = runWidth;
117 m_isCombined = true;
118
119 // Replace my font with the new one.
120 shouldUpdateFont = style()->setFontDescription(description);
121 break;
122 }
123 }
124 }
125
126 if (!m_isCombined)
127 shouldUpdateFont = style()->setFontDescription(originalFont().fontDescription());
128
129 if (shouldUpdateFont)
130 style()->font().update(style()->font().fontSelector());
131
132 if (m_isCombined) {
133 DEFINE_STATIC_LOCAL(String, objectReplacementCharacterString, (&objectReplacementCharacter, 1));
134 RenderText::setTextInternal(objectReplacementCharacterString.impl());
135 }
136 }
137
138 } // namespace WebCore
139