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/*
* Copyright (C) Research In Motion Limited 2010-2012. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "SVGTextMetricsBuilder.h"
#include "RenderChildIterator.h"
#include "RenderSVGInline.h"
#include "RenderSVGInlineText.h"
#include "RenderSVGText.h"
namespace WebCore {
SVGTextMetricsBuilder::SVGTextMetricsBuilder()
: m_text(0)
, m_run(StringView())
, m_textPosition(0)
, m_isComplexText(false)
, m_totalWidth(0)
{
}
inline bool SVGTextMetricsBuilder::currentCharacterStartsSurrogatePair() const
{
return U16_IS_LEAD(m_run[m_textPosition]) && (m_textPosition + 1) < m_run.length() && U16_IS_TRAIL(m_run[m_textPosition + 1]);
}
bool SVGTextMetricsBuilder::advance()
{
m_textPosition += m_currentMetrics.length();
if (m_textPosition >= m_run.length())
return false;
if (m_isComplexText)
advanceComplexText();
else
advanceSimpleText();
return m_currentMetrics.length() > 0;
}
void SVGTextMetricsBuilder::advanceSimpleText()
{
GlyphBuffer glyphBuffer;
unsigned metricsLength = m_simpleWidthIterator->advance(m_textPosition + 1, &glyphBuffer);
if (!metricsLength) {
m_currentMetrics = SVGTextMetrics();
return;
}
float currentWidth = m_simpleWidthIterator->runWidthSoFar() - m_totalWidth;
m_totalWidth = m_simpleWidthIterator->runWidthSoFar();
m_currentMetrics = SVGTextMetrics(*m_text, metricsLength, currentWidth);
}
void SVGTextMetricsBuilder::advanceComplexText()
{
unsigned metricsLength = currentCharacterStartsSurrogatePair() ? 2 : 1;
m_currentMetrics = SVGTextMetrics::measureCharacterRange(*m_text, m_textPosition, metricsLength);
m_complexStartToCurrentMetrics = SVGTextMetrics::measureCharacterRange(*m_text, 0, m_textPosition + metricsLength);
ASSERT(m_currentMetrics.length() == metricsLength);
// Frequent case for Arabic text: when measuring a single character the arabic isolated form is taken
// when rendering the glyph "in context" (with it's surrounding characters) it changes due to shaping.
// So whenever currentWidth != currentMetrics.width(), we are processing a text run whose length is
// not equal to the sum of the individual lengths of the glyphs, when measuring them isolated.
float currentWidth = m_complexStartToCurrentMetrics.width() - m_totalWidth;
if (currentWidth != m_currentMetrics.width())
m_currentMetrics.setWidth(currentWidth);
m_totalWidth = m_complexStartToCurrentMetrics.width();
}
void SVGTextMetricsBuilder::initializeMeasurementWithTextRenderer(RenderSVGInlineText& text)
{
m_text = &text;
m_textPosition = 0;
m_currentMetrics = SVGTextMetrics();
m_complexStartToCurrentMetrics = SVGTextMetrics();
m_totalWidth = 0;
const FontCascade& scaledFont = text.scaledFont();
m_run = SVGTextMetrics::constructTextRun(text);
m_isComplexText = scaledFont.codePath(m_run) == FontCascade::Complex;
if (m_isComplexText)
m_simpleWidthIterator = nullptr;
else
m_simpleWidthIterator = std::make_unique<WidthIterator>(&scaledFont, m_run);
}
struct MeasureTextData {
MeasureTextData(SVGCharacterDataMap* characterDataMap)
: allCharactersMap(characterDataMap)
, lastCharacter(0)
, processRenderer(false)
, valueListPosition(0)
, skippedCharacters(0)
{
}
SVGCharacterDataMap* allCharactersMap;
UChar lastCharacter;
bool processRenderer;
unsigned valueListPosition;
unsigned skippedCharacters;
};
void SVGTextMetricsBuilder::measureTextRenderer(RenderSVGInlineText& text, MeasureTextData* data)
{
SVGTextLayoutAttributes* attributes = text.layoutAttributes();
Vector<SVGTextMetrics>* textMetricsValues = &attributes->textMetricsValues();
if (data->processRenderer) {
if (data->allCharactersMap)
attributes->clear();
else
textMetricsValues->clear();
}
initializeMeasurementWithTextRenderer(text);
bool preserveWhiteSpace = text.style().whiteSpace() == WhiteSpace::Pre;
int surrogatePairCharacters = 0;
while (advance()) {
UChar currentCharacter = m_run[m_textPosition];
if (currentCharacter == ' ' && !preserveWhiteSpace && (!data->lastCharacter || data->lastCharacter == ' ')) {
if (data->processRenderer)
textMetricsValues->append(SVGTextMetrics(SVGTextMetrics::SkippedSpaceMetrics));
if (data->allCharactersMap)
data->skippedCharacters += m_currentMetrics.length();
continue;
}
if (data->processRenderer) {
if (data->allCharactersMap) {
const SVGCharacterDataMap::const_iterator it = data->allCharactersMap->find(data->valueListPosition + m_textPosition - data->skippedCharacters - surrogatePairCharacters + 1);
if (it != data->allCharactersMap->end())
attributes->characterDataMap().set(m_textPosition + 1, it->value);
}
textMetricsValues->append(m_currentMetrics);
}
if (data->allCharactersMap && currentCharacterStartsSurrogatePair())
surrogatePairCharacters++;
data->lastCharacter = currentCharacter;
}
if (!data->allCharactersMap)
return;
data->valueListPosition += m_textPosition - data->skippedCharacters;
data->skippedCharacters = 0;
}
void SVGTextMetricsBuilder::walkTree(RenderElement& start, RenderSVGInlineText* stopAtLeaf, MeasureTextData* data)
{
for (auto& child : childrenOfType<RenderObject>(start)) {
if (is<RenderSVGInlineText>(child)) {
auto& text = downcast<RenderSVGInlineText>(child);
if (stopAtLeaf && stopAtLeaf != &text) {
data->processRenderer = false;
measureTextRenderer(text, data);
continue;
}
data->processRenderer = true;
measureTextRenderer(text, data);
if (stopAtLeaf)
return;
continue;
}
if (!is<RenderSVGInline>(child))
continue;
walkTree(downcast<RenderSVGInline>(child), stopAtLeaf, data);
}
}
void SVGTextMetricsBuilder::measureTextRenderer(RenderSVGInlineText& text)
{
auto* textRoot = RenderSVGText::locateRenderSVGTextAncestor(text);
if (!textRoot)
return;
MeasureTextData data(nullptr);
walkTree(*textRoot, &text, &data);
}
void SVGTextMetricsBuilder::buildMetricsAndLayoutAttributes(RenderSVGText& textRoot, RenderSVGInlineText* stopAtLeaf, SVGCharacterDataMap& allCharactersMap)
{
MeasureTextData data(&allCharactersMap);
walkTree(textRoot, stopAtLeaf, &data);
}
}