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 "core/rendering/RenderCombineText.h"
23
24 #include "core/rendering/RenderBlockFlow.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 m_isCombined = false;
46 }
47
48 m_needsFontUpdate = true;
49 }
50
setTextInternal(PassRefPtr<StringImpl> text)51 void RenderCombineText::setTextInternal(PassRefPtr<StringImpl> text)
52 {
53 RenderText::setTextInternal(text);
54
55 m_needsFontUpdate = true;
56 }
57
width(unsigned from,unsigned length,const Font & font,float xPosition,TextDirection direction,HashSet<const SimpleFontData * > * fallbackFonts,GlyphOverflow * glyphOverflow) const58 float RenderCombineText::width(unsigned from, unsigned length, const Font& font, float xPosition, TextDirection direction, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
59 {
60 if (!length)
61 return 0;
62
63 if (hasEmptyText())
64 return 0;
65
66 if (m_isCombined)
67 return font.fontDescription().computedSize();
68
69 return RenderText::width(from, length, font, xPosition, direction, fallbackFonts, glyphOverflow);
70 }
71
adjustTextOrigin(FloatPoint & textOrigin,const FloatRect & boxRect) const72 void RenderCombineText::adjustTextOrigin(FloatPoint& textOrigin, const FloatRect& boxRect) const
73 {
74 if (m_isCombined)
75 textOrigin.move(boxRect.height() / 2 - ceilf(m_combinedTextWidth) / 2, style()->font().fontDescription().computedPixelSize());
76 }
77
getStringToRender(int start,StringView & string,int & length) const78 void RenderCombineText::getStringToRender(int start, StringView& string, int& length) const
79 {
80 ASSERT(start >= 0);
81 if (m_isCombined) {
82 string = StringView(m_renderingText.impl());
83 length = string.length();
84 return;
85 }
86
87 string = text().createView(start, length);
88 }
89
combineText()90 void RenderCombineText::combineText()
91 {
92 if (!m_needsFontUpdate)
93 return;
94
95 m_isCombined = false;
96 m_needsFontUpdate = false;
97
98 // CSS3 spec says text-combine works only in vertical writing mode.
99 if (style()->isHorizontalWritingMode())
100 return;
101
102 TextRun run = RenderBlockFlow::constructTextRun(this, originalFont(), this, style(), style()->direction());
103 FontDescription description = originalFont().fontDescription();
104 float emWidth = description.computedSize() * textCombineMargin;
105 bool shouldUpdateFont = false;
106
107 description.setOrientation(Horizontal); // We are going to draw combined text horizontally.
108 m_combinedTextWidth = originalFont().width(run);
109 m_isCombined = m_combinedTextWidth <= emWidth;
110
111 FontSelector* fontSelector = style()->font().fontSelector();
112
113 if (m_isCombined)
114 shouldUpdateFont = style()->setFontDescription(description); // Need to change font orientation to horizontal.
115 else {
116 // Need to try compressed glyphs.
117 static const FontWidthVariant widthVariants[] = { HalfWidth, ThirdWidth, QuarterWidth };
118 for (size_t i = 0 ; i < WTF_ARRAY_LENGTH(widthVariants) ; ++i) {
119 description.setWidthVariant(widthVariants[i]);
120 Font compressedFont = Font(description);
121 compressedFont.update(fontSelector);
122 float runWidth = compressedFont.width(run);
123 if (runWidth <= emWidth) {
124 m_combinedTextWidth = runWidth;
125 m_isCombined = true;
126
127 // Replace my font with the new one.
128 shouldUpdateFont = style()->setFontDescription(description);
129 break;
130 }
131 }
132 }
133
134 if (!m_isCombined)
135 shouldUpdateFont = style()->setFontDescription(originalFont().fontDescription());
136
137 if (shouldUpdateFont)
138 style()->font().update(fontSelector);
139
140 if (m_isCombined) {
141 DEFINE_STATIC_LOCAL(String, objectReplacementCharacterString, (&objectReplacementCharacter, 1));
142 m_renderingText = text();
143 RenderText::setTextInternal(objectReplacementCharacterString.impl());
144 }
145 }
146
147 } // namespace WebCore
148