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#include "config.h"
21
22#include "core/rendering/svg/SVGTextMetrics.h"
23
24#include "core/rendering/svg/RenderSVGInlineText.h"
25#include "core/rendering/svg/SVGTextRunRenderingContext.h"
26
27namespace blink {
28
29SVGTextMetrics::SVGTextMetrics()
30    : m_width(0)
31    , m_height(0)
32    , m_length(0)
33    , m_glyph(0)
34{
35}
36
37SVGTextMetrics::SVGTextMetrics(SVGTextMetrics::MetricsType)
38    : m_width(0)
39    , m_height(0)
40    , m_length(1)
41    , m_glyph(0)
42{
43}
44
45SVGTextMetrics::SVGTextMetrics(RenderSVGInlineText* textRenderer, const TextRun& run)
46{
47    ASSERT(textRenderer);
48
49    float scalingFactor = textRenderer->scalingFactor();
50    ASSERT(scalingFactor);
51
52    const Font& scaledFont = textRenderer->scaledFont();
53    int length = 0;
54
55    // Calculate width/height using the scaled font, divide this result by the scalingFactor afterwards.
56    m_width = scaledFont.width(run, length, m_glyph) / scalingFactor;
57    m_height = scaledFont.fontMetrics().floatHeight() / scalingFactor;
58
59    ASSERT(length >= 0);
60    m_length = static_cast<unsigned>(length);
61}
62
63TextRun SVGTextMetrics::constructTextRun(RenderSVGInlineText* text, unsigned position, unsigned length)
64{
65    ASSERT(text->style());
66    return constructTextRun(text, position, length, text->style()->direction());
67}
68
69TextRun SVGTextMetrics::constructTextRun(RenderSVGInlineText* text, unsigned position, unsigned length, TextDirection textDirection)
70{
71    RenderStyle* style = text->style();
72    ASSERT(style);
73
74    TextRun run(static_cast<const LChar*>(0) // characters, will be set below if non-zero.
75                , 0 // length, will be set below if non-zero.
76                , 0 // xPos, only relevant with allowTabs=true
77                , 0 // padding, only relevant for justified text, not relevant for SVG
78                , TextRun::AllowTrailingExpansion
79                , textDirection
80                , isOverride(style->unicodeBidi()) /* directionalOverride */);
81
82    if (length) {
83        if (text->is8Bit())
84            run.setText(text->characters8() + position, length);
85        else
86            run.setText(text->characters16() + position, length);
87    }
88
89    if (textRunNeedsRenderingContext(style->font()))
90        run.setRenderingContext(SVGTextRunRenderingContext::create(text));
91
92    // We handle letter & word spacing ourselves.
93    run.disableSpacing();
94
95    // Propagate the maximum length of the characters buffer to the TextRun, even when we're only processing a substring.
96    run.setCharactersLength(text->textLength() - position);
97    ASSERT(run.charactersLength() >= run.length());
98    return run;
99}
100
101SVGTextMetrics SVGTextMetrics::measureCharacterRange(RenderSVGInlineText* text, unsigned position, unsigned length, TextDirection textDirection)
102{
103    ASSERT(text);
104    return SVGTextMetrics(text, constructTextRun(text, position, length, textDirection));
105}
106
107SVGTextMetrics SVGTextMetrics::measureCharacterRange(RenderSVGInlineText* text, unsigned position, unsigned length)
108{
109    ASSERT(text);
110    return SVGTextMetrics(text, constructTextRun(text, position, length));
111}
112
113SVGTextMetrics::SVGTextMetrics(RenderSVGInlineText* text, unsigned position, unsigned length, float width, Glyph glyphNameGlyphId)
114{
115    ASSERT(text);
116
117    bool needsContext = textRunNeedsRenderingContext(text->style()->font());
118    float scalingFactor = text->scalingFactor();
119    ASSERT(scalingFactor);
120
121    m_width = width / scalingFactor;
122    m_height = text->scaledFont().fontMetrics().floatHeight() / scalingFactor;
123    m_glyph = needsContext ? glyphNameGlyphId : 0;
124
125    m_length = length;
126}
127
128}
129