1/*
2 * Copyright (C) Research In Motion Limited 2010-2012. 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#ifndef SVGTextLayoutEngine_h
21#define SVGTextLayoutEngine_h
22
23#include "core/rendering/svg/SVGTextChunkBuilder.h"
24#include "core/rendering/svg/SVGTextFragment.h"
25#include "core/rendering/svg/SVGTextLayoutAttributes.h"
26#include "core/rendering/svg/SVGTextMetrics.h"
27#include "platform/graphics/Path.h"
28#include "wtf/Vector.h"
29
30namespace blink {
31
32class RenderObject;
33class RenderStyle;
34class RenderSVGInlineText;
35class SVGInlineTextBox;
36
37// SVGTextLayoutEngine performs the second layout phase for SVG text.
38//
39// The InlineBox tree was created, containing the text chunk information, necessary to apply
40// certain SVG specific text layout properties (text-length adjustments and text-anchor).
41// The second layout phase uses the SVGTextLayoutAttributes stored in the individual
42// RenderSVGInlineText renderers to compute the final positions for each character
43// which are stored in the SVGInlineTextBox objects.
44
45class SVGTextLayoutEngine {
46    WTF_MAKE_NONCOPYABLE(SVGTextLayoutEngine);
47public:
48    SVGTextLayoutEngine(Vector<SVGTextLayoutAttributes*>&);
49
50    Vector<SVGTextLayoutAttributes*>& layoutAttributes() { return m_layoutAttributes; }
51
52    void beginTextPathLayout(RenderObject*, SVGTextLayoutEngine& lineLayout);
53    void endTextPathLayout();
54
55    void layoutInlineTextBox(SVGInlineTextBox*);
56    void finishLayout();
57
58private:
59    void updateCharacterPositionIfNeeded(float& x, float& y);
60    void updateCurrentTextPosition(float x, float y, float glyphAdvance);
61    void updateRelativePositionAdjustmentsIfNeeded(float dx, float dy);
62
63    void recordTextFragment(SVGInlineTextBox*, const Vector<SVGTextMetrics>&);
64    bool parentDefinesTextLength(RenderObject*) const;
65
66    void layoutTextOnLineOrPath(SVGInlineTextBox*, const RenderSVGInlineText&, const RenderStyle&);
67    void finalizeTransformMatrices(Vector<SVGInlineTextBox*>&);
68
69    bool currentLogicalCharacterAttributes(SVGTextLayoutAttributes*&);
70    bool currentLogicalCharacterMetrics(SVGTextLayoutAttributes*&, SVGTextMetrics&);
71    bool currentVisualCharacterMetrics(SVGInlineTextBox*, const Vector<SVGTextMetrics>&, SVGTextMetrics&);
72
73    void advanceToNextLogicalCharacter(const SVGTextMetrics&);
74    void advanceToNextVisualCharacter(const SVGTextMetrics&);
75
76private:
77    Vector<SVGTextLayoutAttributes*>& m_layoutAttributes;
78
79    Vector<SVGInlineTextBox*> m_lineLayoutBoxes;
80    Vector<SVGInlineTextBox*> m_pathLayoutBoxes;
81    SVGTextChunkBuilder m_chunkLayoutBuilder;
82
83    SVGTextFragment m_currentTextFragment;
84    unsigned m_layoutAttributesPosition;
85    unsigned m_logicalCharacterOffset;
86    unsigned m_logicalMetricsListOffset;
87    unsigned m_visualCharacterOffset;
88    unsigned m_visualMetricsListOffset;
89    float m_x;
90    float m_y;
91    float m_dx;
92    float m_dy;
93    bool m_isVerticalText;
94    bool m_inPathLayout;
95
96    // Text on path layout
97    Path::PositionCalculator* m_textPathCalculator;
98    float m_textPathLength;
99    float m_textPathStartOffset;
100    float m_textPathCurrentOffset;
101    float m_textPathSpacing;
102    float m_textPathScaling;
103};
104
105} // namespace blink
106
107#endif
108