highlighter.cpp Example File
richtext/syntaxhighlighter/highlighter.cpp
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** Copyright (C) 2005-2005 Trolltech AS. All rights reserved.
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** This file is part of the documentation of the Qt Toolkit.
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#include <QtGui>
#include "highlighter.h"
Highlighter::Highlighter(QObject *parent)
: QObject(parent)
{
}
void Highlighter::addToDocument(QTextDocument *doc)
{
connect(doc, SIGNAL(contentsChange(int, int, int)),
this, SLOT(highlight(int, int, int)));
}
void Highlighter::addMapping(const QString &pattern,
const QTextCharFormat &format)
{
mappings[pattern] = format;
}
void Highlighter::highlight(int position, int removed, int added)
{
QTextDocument *doc = qobject_cast<QTextDocument *>(sender());
QTextBlock block = doc->findBlock(position);
if (!block.isValid())
return;
QTextBlock endBlock;
if (added > removed)
endBlock = doc->findBlock(position + added);
else
endBlock = block;
while (block.isValid() && !(endBlock < block)) {
highlightBlock(block);
block = block.next();
}
}
void Highlighter::highlightBlock(QTextBlock block)
{
QTextLayout *layout = block.layout();
const QString text = block.text();
QList<QTextLayout::FormatRange> overrides;
foreach (QString pattern, mappings.keys()) {
QRegExp expression(pattern);
int i = text.indexOf(expression);
while (i >= 0) {
QTextLayout::FormatRange range;
range.start = i;
range.length = expression.matchedLength();
range.format = mappings[pattern];
overrides << range;
i = text.indexOf(expression, i + expression.matchedLength());
}
}
layout->setAdditionalFormats(overrides);
const_cast<QTextDocument *>(block.document())->markContentsDirty(
block.position(), block.length());
}