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#if ENABLE(SVG)
23#include "SVGTextMetrics.h"
24
25#include "RenderSVGInlineText.h"
26#include "SVGTextRunRenderingContext.h"
27#include "WidthIterator.h"
28
29namespace WebCore {
30
31SVGTextMetrics::SVGTextMetrics()
32    : m_width(0)
33    , m_height(0)
34    , m_length(0)
35{
36}
37
38SVGTextMetrics::SVGTextMetrics(SVGTextMetrics::MetricsType)
39    : m_width(0)
40    , m_height(0)
41    , m_length(1)
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.name) / scalingFactor;
57    m_height = scaledFont.fontMetrics().floatHeight() / scalingFactor;
58
59    m_glyph.unicodeString = run.is8Bit() ? String(run.characters8(), length) : String(run.characters16(), length);
60    m_glyph.isValid = true;
61
62    ASSERT(length >= 0);
63    m_length = static_cast<unsigned>(length);
64}
65
66TextRun SVGTextMetrics::constructTextRun(RenderSVGInlineText* text, const UChar* characters, unsigned position, unsigned length)
67{
68    RenderStyle* style = text->style();
69    ASSERT(style);
70
71    TextRun run(characters + position
72                , length
73                , 0 /* xPos, only relevant with allowTabs=true */
74                , 0 /* padding, only relevant for justified text, not relevant for SVG */
75                , TextRun::AllowTrailingExpansion
76                , style->direction()
77                , isOverride(style->unicodeBidi()) /* directionalOverride */);
78
79    if (textRunNeedsRenderingContext(style->font()))
80        run.setRenderingContext(SVGTextRunRenderingContext::create(text));
81
82    run.disableRoundingHacks();
83
84    // We handle letter & word spacing ourselves.
85    run.disableSpacing();
86
87    // Propagate the maximum length of the characters buffer to the TextRun, even when we're only processing a substring.
88    run.setCharactersLength(text->textLength() - position);
89    ASSERT(run.charactersLength() >= run.length());
90    return run;
91}
92
93SVGTextMetrics SVGTextMetrics::measureCharacterRange(RenderSVGInlineText* text, unsigned position, unsigned length)
94{
95    ASSERT(text);
96    return SVGTextMetrics(text, constructTextRun(text, text->characters(), position, length));
97}
98
99SVGTextMetrics::SVGTextMetrics(RenderSVGInlineText* text, unsigned position, unsigned length, float width, const String& glyphName)
100{
101    ASSERT(text);
102
103    bool needsContext = textRunNeedsRenderingContext(text->style()->font());
104    float scalingFactor = text->scalingFactor();
105    ASSERT(scalingFactor);
106
107    m_width = width / scalingFactor;
108    m_height = text->scaledFont().fontMetrics().floatHeight() / scalingFactor;
109    if (needsContext) {
110        m_glyph.isValid = true;
111        m_glyph.unicodeString = String(text->characters() + position, length);
112        m_glyph.name = glyphName;
113    }
114
115    m_length = length;
116}
117
118}
119
120#endif // ENABLE(SVG)
121