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 "Path.h"
24#include "SVGTextChunkBuilder.h"
25#include "SVGTextFragment.h"
26#include "SVGTextLayoutAttributes.h"
27
28namespace WebCore {
29
30class RenderObject;
31class RenderStyle;
32class RenderSVGInlineText;
33class SVGElement;
34class SVGInlineTextBox;
35class SVGRenderStyle;
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    SVGTextChunkBuilder& chunkLayoutBuilder() { return m_chunkLayoutBuilder; }
52
53    void beginTextPathLayout(RenderObject*, SVGTextLayoutEngine& lineLayout);
54    void endTextPathLayout();
55
56    void layoutInlineTextBox(SVGInlineTextBox*);
57    void finishLayout();
58
59private:
60    void updateCharacerPositionIfNeeded(float& x, float& y);
61    void updateCurrentTextPosition(float x, float y, float glyphAdvance);
62    void updateRelativePositionAdjustmentsIfNeeded(float dx, float dy);
63
64    void recordTextFragment(SVGInlineTextBox*, Vector<SVGTextMetrics>&);
65    bool parentDefinesTextLength(RenderObject*) const;
66
67    void layoutTextOnLineOrPath(SVGInlineTextBox*, RenderSVGInlineText*, const RenderStyle*);
68    void finalizeTransformMatrices(Vector<SVGInlineTextBox*>&);
69
70    bool currentLogicalCharacterAttributes(SVGTextLayoutAttributes*&);
71    bool currentLogicalCharacterMetrics(SVGTextLayoutAttributes*&, SVGTextMetrics&);
72    bool currentVisualCharacterMetrics(SVGInlineTextBox*, Vector<SVGTextMetrics>&, SVGTextMetrics&);
73
74    void advanceToNextLogicalCharacter(const SVGTextMetrics&);
75    void advanceToNextVisualCharacter(const SVGTextMetrics&);
76
77private:
78    Vector<SVGTextLayoutAttributes*>& m_layoutAttributes;
79
80    Vector<SVGInlineTextBox*> m_lineLayoutBoxes;
81    Vector<SVGInlineTextBox*> m_pathLayoutBoxes;
82    SVGTextChunkBuilder m_chunkLayoutBuilder;
83
84    SVGTextFragment m_currentTextFragment;
85    unsigned m_layoutAttributesPosition;
86    unsigned m_logicalCharacterOffset;
87    unsigned m_logicalMetricsListOffset;
88    unsigned m_visualCharacterOffset;
89    unsigned m_visualMetricsListOffset;
90    float m_x;
91    float m_y;
92    float m_dx;
93    float m_dy;
94    bool m_isVerticalText;
95    bool m_inPathLayout;
96
97    // Text on path layout
98    Path m_textPath;
99    float m_textPathLength;
100    float m_textPathStartOffset;
101    float m_textPathCurrentOffset;
102    float m_textPathSpacing;
103    float m_textPathScaling;
104};
105
106} // namespace WebCore
107
108#endif
109