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 WebCore {
31
32class RenderObject;
33class RenderStyle;
34class RenderSVGInlineText;
35class SVGElement;
36class SVGInlineTextBox;
37class SVGRenderStyle;
38
39// SVGTextLayoutEngine performs the second layout phase for SVG text.
40//
41// The InlineBox tree was created, containing the text chunk information, necessary to apply
42// certain SVG specific text layout properties (text-length adjustments and text-anchor).
43// The second layout phase uses the SVGTextLayoutAttributes stored in the individual
44// RenderSVGInlineText renderers to compute the final positions for each character
45// which are stored in the SVGInlineTextBox objects.
46
47class SVGTextLayoutEngine {
48    WTF_MAKE_NONCOPYABLE(SVGTextLayoutEngine);
49public:
50    SVGTextLayoutEngine(Vector<SVGTextLayoutAttributes*>&);
51
52    Vector<SVGTextLayoutAttributes*>& layoutAttributes() { return m_layoutAttributes; }
53
54    void beginTextPathLayout(RenderObject*, SVGTextLayoutEngine& lineLayout);
55    void endTextPathLayout();
56
57    void layoutInlineTextBox(SVGInlineTextBox*);
58    void finishLayout();
59
60private:
61    void updateCharacerPositionIfNeeded(float& x, float& y);
62    void updateCurrentTextPosition(float x, float y, float glyphAdvance);
63    void updateRelativePositionAdjustmentsIfNeeded(float dx, float dy);
64
65    void recordTextFragment(SVGInlineTextBox*, Vector<SVGTextMetrics>&);
66    bool parentDefinesTextLength(RenderObject*) const;
67
68    void layoutTextOnLineOrPath(SVGInlineTextBox*, RenderSVGInlineText*, const RenderStyle*);
69    void finalizeTransformMatrices(Vector<SVGInlineTextBox*>&);
70
71    bool currentLogicalCharacterAttributes(SVGTextLayoutAttributes*&);
72    bool currentLogicalCharacterMetrics(SVGTextLayoutAttributes*&, SVGTextMetrics&);
73    bool currentVisualCharacterMetrics(SVGInlineTextBox*, Vector<SVGTextMetrics>&, SVGTextMetrics&);
74
75    void advanceToNextLogicalCharacter(const SVGTextMetrics&);
76    void advanceToNextVisualCharacter(const SVGTextMetrics&);
77
78private:
79    Vector<SVGTextLayoutAttributes*>& m_layoutAttributes;
80
81    Vector<SVGInlineTextBox*> m_lineLayoutBoxes;
82    Vector<SVGInlineTextBox*> m_pathLayoutBoxes;
83    SVGTextChunkBuilder m_chunkLayoutBuilder;
84
85    SVGTextFragment m_currentTextFragment;
86    unsigned m_layoutAttributesPosition;
87    unsigned m_logicalCharacterOffset;
88    unsigned m_logicalMetricsListOffset;
89    unsigned m_visualCharacterOffset;
90    unsigned m_visualMetricsListOffset;
91    float m_x;
92    float m_y;
93    float m_dx;
94    float m_dy;
95    bool m_isVerticalText;
96    bool m_inPathLayout;
97
98    // Text on path layout
99    Path m_textPath;
100    float m_textPathLength;
101    float m_textPathStartOffset;
102    float m_textPathCurrentOffset;
103    float m_textPathSpacing;
104    float m_textPathScaling;
105};
106
107} // namespace WebCore
108
109#endif
110