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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at qt-sales@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qstatictext.h"
#include "qstatictext_p.h"
QT_BEGIN_NAMESPACE
/*!
\class QStaticText
\brief The QStaticText class enables optimized drawing of text when the text and its layout
is updated rarely.
\ingroup multimedia
\ingroup text
\mainclass
QStaticText provides a way to cache layout data for a block of text so that it can be drawn
more efficiently than by using QPainter::drawText() in which the layout information is
recalculated with every call.
The class primarily provides an optimization for cases where text is static over several paint
events. If the text or its layout is changed regularly, QPainter::drawText() is the more
efficient alternative.
\code
class MyWidget: public QWidget
{
public:
MyWidget(QWidget *parent = 0) : QWidget(parent), m_staticText("This is static text")
protected:
void paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.drawStaticText(0, 0, m_staticText);
}
private:
QStaticText m_staticText;
};
\endcode
The QStaticText class can be used to mimic the behavior of QPainter::drawText() to a specific
point with no boundaries, and also when QPainter::drawText() is called with a bounding
rectangle.
If a bounding rectangle is not required, create a QStaticText object without setting a maximum
size. The text will then occupy a single line.
If you set a maximum size on the QStaticText object, this will bound the text. The text will
be formatted so that no line exceeds the given width. When the object is painted, it will
be clipped vertically at the given height. The position of the text is decided by the argument
passed to QPainter::drawStaticText() and can change from call to call without affecting
performance.
\sa QPainter::drawStaticText().
*/
/*!
\fn QStaticText::QStaticText(const QString &text, const QFont &font, const QSizeF &maximumSize)
Constructs a QStaticText object with the given \a text which is to be rendered in the given
\a font and bounded by the given \a maximumSize. If an invalid size is passed for \a maximumSize
the text will be unbounded.
*/
QStaticText::QStaticText(const QString &text, const QFont &font, const QSizeF &sz)
: d_ptr(new QStaticTextPrivate)
{
Q_D(QStaticText);
d->init(text, font, sz);
}
/*!
Destroys the QStaticText.
*/
QStaticText::~QStaticText()
{
Q_D(QStaticText);
delete d;
}
QStaticTextPrivate::QStaticTextPrivate()
: textLayout(0)
{
}
QStaticTextPrivate::~QStaticTextPrivate()
{
delete textLayout;
}
QStaticTextPrivate *QStaticTextPrivate::get(const QStaticText *q)
{
return q->d_ptr;
}
void QStaticTextPrivate::init(const QString &text, const QFont &font, const QSizeF &sz)
{
Q_ASSERT(textLayout == 0);
size = sz;
textLayout = new QTextLayout(text, font);
textLayout->setCacheEnabled(true);
QFontMetrics fontMetrics(font);
textLayout->beginLayout();
int h = size.isValid() ? 0 : -fontMetrics.ascent();
QTextLine line;
while ((line = textLayout->createLine()).isValid()) {
line.setLineWidth(size.isValid() ? size.width() : fontMetrics.width(text));
line.setPosition(QPointF(0, h));
h += line.height();
}
}
QT_END_NAMESPACE
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