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Circle Widget with paint

  

Foundations of Qt Development\Chapter07\widgets\events\circlewidget.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include "circlewidget.h"
#include <QPainter>
#include <QMouseEvent>
#include <QTimer>
CircleWidget::CircleWidget( QWidget *parent ) : QWidget( parent )
{
  r = 0;
  
  timer = new QTimer( this );
  timer->setInterval( 50 );
  
  connect( timer, SIGNAL(timeout()), this, SLOT(timeout()) );
}
QSize CircleWidget::sizeHint() const
{
  return QSize( 200, 200 );
}
void CircleWidget::timeout()
{
  if( r == 0 )
  {
    x = mx;
    y = my;
    
    color = QColor( qrand()%256, qrand()%256, qrand()%256 );
  }
  int dx = mx-x;
  int dy = my-y;
  if( dx*dx+dy*dy <= r*r )
    r++;
  else
    r--;
    
  update();
}
void CircleWidget::paintEvent( QPaintEvent* )
{
  if( r > 0 )
  {
    QPainter painter( this );
    
    painter.setRenderHint( QPainter::Antialiasing );
    
    painter.setPen( color );
    painter.setBrush( color );
    painter.drawEllipse( x-r, y-r, 2*r, 2*r );
  }
}
void CircleWidget::mousePressEvent( QMouseEvent *e )
{
  mx = e->x();
  my = e->y();
  
  timer->start();
}
void CircleWidget::mouseMoveEvent( QMouseEvent *e )
{
  mx = e->x();
  my = e->y();
}
void CircleWidget::mouseReleaseEvent( QMouseEvent *e )
{
  timer->stop();
}

Foundations of Qt Development\Chapter07\widgets\events\circlewidget.h
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#ifndef CIRCLEWIDGET_H
#define CIRCLEWIDGET_H
#include <QWidget>
class QTimer;
class CircleWidget : public QWidget
{
  Q_OBJECT
  
public:
  CircleWidget( QWidget *parent=0 );
  
  QSize sizeHint() const;
private slots:
  void timeout();
  
protected:
  void paintEvent( QPaintEvent* );
  
  void mousePressEvent( QMouseEvent* );
  void mouseMoveEvent( QMouseEvent* );
  void mouseReleaseEvent( QMouseEvent* );
  
private:
  int x, y, r;
  QColor color;
  int mx, my;
  
  QTimer *timer;
};
#endif

Foundations of Qt Development\Chapter07\widgets\events\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include "circlewidget.h"
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  CircleWidget widget;
  widget.show();
  
  return app.exec();
}


Draws a filled-in circle

  
#include <QtGui>
int main(int argc, char* argv[])
{
  QApplication app(argc, argv);
  QPixmap pm(100,100);
  pm.fill();
  QPainter p(&pm);
  p.setRenderHint(QPainter::Antialiasing, true);
  QPen pen(Qt::blue, 2);
  p.setPen(pen);
  QBrush brush(Qt::green);
  p.setBrush(brush);
  p.drawEllipse(10, 10, 80, 80);
  QLabel l;
  l.setPixmap(pm);
  l.show();
  return app.exec();
}


Draw text

  
Foundations of Qt Development\Chapter07\text\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPixmap>
#include <QPainter>
#include <QTextDocument>
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  QPixmap pixmap( 200, 330 );
  pixmap.fill( Qt::white );
  QPainter painter( &pixmap );
  painter.setPen( Qt::black );
    
  QPoint point = QPoint( 10, 20 );
  painter.drawText( point, "You can draw text from a point..." );
  painter.drawLine( point+QPoint(-5, 0), point+QPoint(5, 0) );
  painter.drawLine( point+QPoint(0, -5), point+QPoint(0, 5) );
  
  QRect rect = QRect(10, 30, 180, 20);
  painter.drawText( rect, Qt::AlignCenter, 
                    "...or you can draw it inside a rectangle." );
  painter.drawRect( rect );
  
  rect.translate( 0, 30 );
  
  QFont font = QApplication::font();
  font.setPixelSize( rect.height() );
  painter.setFont( font );
  
  painter.drawText( rect, Qt::AlignRight, "Right." );
  painter.drawText( rect, Qt::AlignLeft, "Left." );
  painter.drawRect( rect );
  
  rect.translate( 0, rect.height()+10 );
  rect.setHeight( QFontMetrics( font ).height() );
  painter.drawText( rect, Qt::AlignRight, "Right." );
  painter.drawText( rect, Qt::AlignLeft, "Left." );
  painter.drawRect( rect );
  
  QTextDocument doc;
  doc.setHtml( "<p>A QTextDocument can be used to present formatted text "
               "in a nice way.</p>"
               "<p align=center>It can be <b>formatted</b> "
               "<font size=+2>in</font> <i>different</i> ways.</p>"
               "<p>The text can be really long and contain many "
               "paragraphs. It is properly wrapped and such...</p>" );
  rect.translate( 0, rect.height()+10 );
  rect.setHeight( 160 );
  doc.setTextWidth( rect.width() );
  painter.save();
  painter.translate( rect.topLeft() );
  doc.drawContents( &painter, rect.translated( -rect.topLeft() ) );
  painter.restore();
  painter.drawRect( rect );
  rect.translate( 0, 160 );
  rect.setHeight( doc.size().height()-160 );
  painter.setBrush( Qt::gray );
  painter.drawRect( rect );
  pixmap.save( "text.png" );
  return 0;
}


Linear Gradient

  
#include <QtGui>
int main(int argv, char **args)
{
    QApplication app(argv, args);
    QLinearGradient linearGrad(QPointF(100, 100), QPointF(200, 200));
    linearGrad.setColorAt(0, Qt::black);
    linearGrad.setColorAt(1, Qt::white);
    
    QBrush brush(linearGrad);
    QWidget widget;
    QPalette palette;
    palette.setBrush(widget.backgroundRole(), brush);
    widget.setPalette(palette);
    widget.show();
    return app.exec();
}


Matrix based translation

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
#include <cmath>
class SimpleTransformation : public QWidget
{
    void paintEvent(QPaintEvent *);
};

void SimpleTransformation::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setPen(QPen(Qt::blue, 1, Qt::DashLine));
    painter.drawRect(0, 0, 100, 100);
    painter.rotate(45);
    painter.setFont(QFont("Helvetica", 24));
    painter.setPen(QPen(Qt::black, 1));
    painter.drawText(20, 10, "QMatrix");
}

class CombinedTransformation : public QWidget
{
    void paintEvent(QPaintEvent *);
};

void CombinedTransformation::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setPen(QPen(Qt::blue, 1, Qt::DashLine));
    painter.drawRect(0, 0, 100, 100);
    QMatrix matrix;
    matrix.translate(50, 50);
    matrix.rotate(45);
    matrix.scale(0.5, 1.0);
    painter.setMatrix(matrix);
    painter.setFont(QFont("Helvetica", 24));
    painter.setPen(QPen(Qt::black, 1));
    painter.drawText(20, 10, "QMatrix");
}

class BasicOperations : public QWidget
{
    void paintEvent(QPaintEvent *);
};

void BasicOperations::paintEvent(QPaintEvent *)
{
    double pi = 3.14;
    double a    = pi/180 * 45.0;
    double sina = sin(a);
    double cosa = cos(a);
    QMatrix translationMatrix(1, 0, 0, 1, 50.0, 50.0);
    QMatrix rotationMatrix(cosa, sina, -sina, cosa, 0, 0);
    QMatrix scalingMatrix(0.5, 0, 0, 1.0, 0, 0);
    QMatrix matrix;
    matrix =  scalingMatrix * rotationMatrix * translationMatrix;
    QPainter painter(this);
    painter.setPen(QPen(Qt::blue, 1, Qt::DashLine));
    painter.drawRect(0, 0, 100, 100);
    painter.setMatrix(matrix);
    painter.setFont(QFont("Helvetica", 24));
    painter.setPen(QPen(Qt::black, 1));
    painter.drawText(20, 10, "QMatrix");
}

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    QWidget widget;
    SimpleTransformation *simpleWidget = new SimpleTransformation;
    CombinedTransformation *combinedWidget = new CombinedTransformation;
    BasicOperations *basicWidget = new BasicOperations;
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(simpleWidget);
    layout->addWidget(combinedWidget);
    layout->addWidget(basicWidget);
    widget.setLayout(layout);
    widget.show();
    widget.resize(130, 350);
    return app.exec();
}


Painter

  
#include <QtGui>
int main(int argv, char **args)
{
    QApplication app(argv, args);
    QLinearGradient linearGrad(QPointF(100, 100), QPointF(200, 200));
    linearGrad.setColorAt(0, Qt::black);
    linearGrad.setColorAt(1, Qt::white);
    QBrush brush(linearGrad);
        QPainter painter;
        painter.setBrush(brush);          // set the yellow brush
        painter.setPen(Qt::NoPen);        // do not draw outline
        painter.drawRect(40,30, 200,100); // draw filled rectangle
        painter.setBrush(Qt::NoBrush);    // do not fill
        painter.setPen(Qt::black);            // set black pen, 0 pixel width
        painter.drawRect(10,10, 30,20);   // draw rectangle outline
        painter.end();                    // painting done
    QWidget widget;
    QPalette palette;
    palette.setBrush(widget.backgroundRole(), brush);
    widget.setPalette(palette);
    widget.show();
    return app.exec();
}


Painter path

  

/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    QImage image(100, 100, QImage::Format_RGB32);
    QPainterPath path;
    path.addRect(20, 20, 60, 60);
    path.moveTo(0, 0);
    path.cubicTo(99, 0,  50, 50,  99, 99);
    path.cubicTo(0, 99,  50, 50,  0, 0);
    QPainter painter(&image);
    painter.fillRect(0, 0, 100, 100, Qt::white);
    painter.save();
    painter.translate(0.5, 0.5);
    painter.setPen(QPen(QColor(79, 106, 25), 1, Qt::SolidLine, Qt::FlatCap, Qt::MiterJoin));
    painter.setBrush(QColor(122, 163, 39));
    painter.setRenderHint(QPainter::Antialiasing);
    painter.drawPath(path);
    painter.restore();
    painter.end();
    QLabel lab;
    lab.setPixmap(QPixmap::fromImage(image));
    lab.show();
    return app.exec();
}


Paint picture

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
void myProcessing(const QString &)
{
}
int main()
{
    QWidget myWidget;
    {
        // RECORD
        QPicture picture;
        QPainter painter;
        painter.begin(&picture);           // paint in picture
        painter.drawEllipse(10,20, 80,70); // draw an ellipse
        painter.end();                     // painting done
        picture.save("drawing.pic");       // save picture
    }
    {
        // REPLAY
        QPicture picture;
        picture.load("drawing.pic");           // load picture
        QPainter painter;
        painter.begin(&myImage);               // paint in myImage
        painter.drawPicture(0, 0, picture);    // draw the picture at (0,0)
        painter.end();                         // painting done
    }
    QPicture myPicture;
    {
        // FORMATS
        QStringList list = QPicture::inputFormatList();
        foreach (QString string, list)
            myProcessing(string);
    }
    {
        // OUTPUT
        QStringList list = QPicture::outputFormatList();
        foreach (QString string, list)
            myProcessing(string);
    }
    {
        // PIC READ
        QPictureIO iio;
        QPixmap  pixmap;
        iio.setFileName("vegeburger.pic");
        if (iio.read()) {        // OK
            QPicture picture = iio.picture();
            QPainter painter(&pixmap);
            painter.drawPicture(0, 0, picture);
        }
    }
    {
        QPixmap pixmap;
        // PIC WRITE
        QPictureIO iio;
        QPicture   picture;
        QPainter painter(&picture);
        painter.drawPixmap(0, 0, pixmap);
        iio.setPicture(picture);
        iio.setFileName("vegeburger.pic");
        iio.setFormat("PIC");
        if (iio.write())
            return true; // returned true if written successfully
    }
}


Paint rectangle

  
Foundations of Qt Development\Chapter05\bardelegate\bardelegate.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QPainter>
#include <QModelIndex>
#include "bardelegate.h"
BarDelegate::BarDelegate( QObject *parent ) : QAbstractItemDelegate( parent ) { }
void BarDelegate::paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
  if( option.state & QStyle::State_Selected )
    painter->fillRect( option.rect, option.palette.highlight() );
  int value = index.model()->data( index, Qt::DisplayRole ).toInt();
  double factor = double(value)/100.0;
  
  painter->save();
  if( factor > 1 )
  {
    painter->setBrush( Qt::red );
    factor = 1;
  }
  else
    painter->setBrush( QColor( 0, int(factor*255), 255-int(factor*255) ) );
  painter->setPen( Qt::black );
  painter->drawRect( option.rect.x()+2, option.rect.y()+2, int(factor*(option.rect.width()-5)), option.rect.height()-5 );
  painter->restore();
}
QSize BarDelegate::sizeHint( const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
  return QSize( 45, 15 ); 
}

Foundations of Qt Development\Chapter05\bardelegate\bardelegate.h
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#ifndef BARDELEGATE_H
#define BARDELEGATE_H
#include <QAbstractItemDelegate>
class BarDelegate : public QAbstractItemDelegate
{
public:
  BarDelegate( QObject *parent = 0 );
  void paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const;
  QSize sizeHint( const QStyleOptionViewItem &option, const QModelIndex &index ) const;
};
#endif // BARDELEGATE_H

Foundations of Qt Development\Chapter05\bardelegate\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QTableView>
#include <QStandardItemModel>
#include "bardelegate.h"
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  QTableView table;
  QStandardItemModel model( 10, 2 ); 
  for( int r=0; r<10; ++r )
  {
    QStandardItem *item = new QStandardItem( QString("Row %1").arg(r+1) );
    item->setEditable( false ); 
    model.setItem( r, 0, item );
    
    model.setItem( r, 1, new QStandardItem( QString::number((r*30)%100 )) );  
  }
  table.setModel( &model );
  
  BarDelegate delegate;
  table.setItemDelegateForColumn( 1, &delegate );
  table.show();
  
  return app.exec();
}


QConicalGradient

  

Foundations of Qt Development\Chapter07\brushgradients\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPainter>
#include <QBrush>
#include <QPixmap>
void createBrushShot( QBrush brush, QString name )
{
  QPixmap pixmap( 200, 200 );
  pixmap.fill( Qt::white );
  
  QPainter painter( &pixmap );
  
  painter.setBrush( brush );
  painter.drawRect( pixmap.rect() );
  
  pixmap.save( QString("%1.png").arg( name ) );
}
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  QLinearGradient linGrad( QPointF(80, 80), QPoint( 120, 120 ) );
  linGrad.setColorAt( 0, Qt::black );
  linGrad.setColorAt( 1, Qt::white );
    
  linGrad.setSpread( QGradient::PadSpread );
  createBrushShot( QBrush( linGrad ), "LinearPad" );
  linGrad.setSpread( QGradient::RepeatSpread );
  createBrushShot( QBrush( linGrad ), "LinearRepeat" );
  linGrad.setSpread( QGradient::ReflectSpread );
  createBrushShot( QBrush( linGrad ), "LinearReflect" );  
  QRadialGradient radGrad( QPointF(100, 100), 30 );
  radGrad.setColorAt( 0, Qt::black );
  radGrad.setColorAt( 1, Qt::white );
  
  radGrad.setSpread( QGradient::PadSpread );
  createBrushShot( QBrush( radGrad ), "RadialPad" );
  radGrad.setSpread( QGradient::RepeatSpread );
  createBrushShot( QBrush( radGrad ), "RadialRepeat" );
  radGrad.setSpread( QGradient::ReflectSpread );
  createBrushShot( QBrush( radGrad ), "RadialReflect" );
  
  QConicalGradient conGrad( QPointF(100, 100), -45.0 );
  conGrad.setColorAt( 0, Qt::black );
  conGrad.setColorAt( 1, Qt::white );
  
  conGrad.setSpread( QGradient::PadSpread );
  createBrushShot( QBrush( conGrad ), "ConicalPad" );
  conGrad.setSpread( QGradient::RepeatSpread );
  createBrushShot( QBrush( conGrad ), "ConicalRepeat" );
  conGrad.setSpread( QGradient::ReflectSpread );
  createBrushShot( QBrush( conGrad ), "ConicalReflect" );
  
  QBrush textureBrush( QImage("texture.png") );
  createBrushShot( textureBrush, "TextureBrush" );
  
  return 0;
}


QLinearGradient and QPainter

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef PAINTWIDGET_H
#define PAINTWIDGET_H
#include <QWidget>
class QPaintEvent;
class PaintWidget : public QWidget
{
    Q_OBJECT
public:
    PaintWidget(QWidget *parent = 0);
protected:
    void paintEvent(QPaintEvent *event);
};
#endif


#include <QtGui>
#include "paintwidget.h"
PaintWidget::PaintWidget(QWidget *parent)
    : QWidget(parent)
{
}
void PaintWidget::paintEvent(QPaintEvent *event)
{
    QLinearGradient gradient1(rect().topLeft(), rect().bottomRight());
    gradient1.setColorAt(0, QColor("#ffffcc"));
    gradient1.setColorAt(1, QColor("#ccccff"));
    QRectF ellipseRect(width()*0.25, height()*0.25, width()*0.5, height()*0.5);
    QLinearGradient gradient2(ellipseRect.topLeft(), ellipseRect.bottomRight());
    gradient2.setColorAt(0, QColor("#ccccff"));
    gradient2.setColorAt(1, QColor("#ffffcc"));
    QPainter painter;
    painter.begin(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.fillRect(rect(), QBrush(gradient1));
    painter.setBrush(QBrush(gradient2));
    painter.drawEllipse(ellipseRect);
    painter.end();
}


#include <QtGui>
#include "paintwidget.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    PaintWidget window;
    window.show();
    return app.exec();
}


Renderer pattern

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef CLIPWINDOW_H
#define CLIPWINDOW_H
#include <QMainWindow>
class QClipboard;
class QComboBox;
class QLabel;
class QListWidget;
class QMimeData;
class QWidget;
class ClipWindow : public QMainWindow
{
    Q_OBJECT
public:
    ClipWindow(QWidget *parent = 0);
public slots:
    void updateClipboard();
    void updateData(const QString &format);
private:
    int currentItem;
    QClipboard *clipboard;
    QComboBox *mimeTypeCombo;
    QLabel *dataInfoLabel;
    QListWidget *previousItems;
};
#endif






#include <QtGui>
#include "clipwindow.h"
ClipWindow::ClipWindow(QWidget *parent)
    : QMainWindow(parent)
{
    clipboard = QApplication::clipboard();
    QWidget *centralWidget = new QWidget(this);
    QWidget *currentItem = new QWidget(centralWidget);
    QLabel *mimeTypeLabel = new QLabel(tr("MIME types:"), currentItem);
    mimeTypeCombo = new QComboBox(currentItem);
    QLabel *dataLabel = new QLabel(tr("Data:"), currentItem);
    dataInfoLabel = new QLabel("", currentItem);
    previousItems = new QListWidget(centralWidget);
    connect(clipboard, SIGNAL(dataChanged()), this, SLOT(updateClipboard()));
    connect(mimeTypeCombo, SIGNAL(activated(const QString &)),
            this, SLOT(updateData(const QString &)));
    QVBoxLayout *currentLayout = new QVBoxLayout(currentItem);
    currentLayout->addWidget(mimeTypeLabel);
    currentLayout->addWidget(mimeTypeCombo);
    currentLayout->addWidget(dataLabel);
    currentLayout->addWidget(dataInfoLabel);
    currentLayout->addStretch(1);
    QHBoxLayout *mainLayout = new QHBoxLayout(centralWidget);
    mainLayout->addWidget(currentItem, 1);
    mainLayout->addWidget(previousItems);
    setCentralWidget(centralWidget);
    setWindowTitle(tr("Clipboard"));
}

void ClipWindow::updateClipboard()
{
    QStringList formats = clipboard->mimeData()->formats();
    QByteArray data = clipboard->mimeData()->data(format);

    mimeTypeCombo->clear();
    mimeTypeCombo->insertStringList(formats);
    int size = clipboard->mimeData()->data(formats[0]).size();
    QListWidgetItem *newItem = new QListWidgetItem(previousItems);
    newItem->setText(tr("%1 (%2 bytes)").arg(formats[0]).arg(size));
    updateData(formats[0]);
}

void ClipWindow::updateData(const QString &format)
{
    QByteArray data = clipboard->mimeData()->data(format);
    dataInfoLabel->setText(tr("%1 bytes").arg(data.size()));
}




#include <QApplication>
#include "clipwindow.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    ClipWindow *window = new ClipWindow;
    window->resize(640, 480);
    window->show();
    return app.exec();
}


Set pen and brush for QPainter

  
Foundations of Qt Development\Chapter07\penbrush\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPixmap>
#include <QPainter>
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  QPixmap pixmap( 200, 100 );
  QPainter painter( &pixmap );
  
  painter.setPen( Qt::red );
  painter.setBrush( Qt::yellow );
  return 0;
}


Set render hint to QPainter::Antialiasing

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
class MyWidget : public QWidget
{
public:
    MyWidget();
protected:
    void paintEvent(QPaintEvent *);
};
MyWidget::MyWidget()
{
    QPalette palette(MyWidget::palette());
    palette.setColor(backgroundRole(), Qt::white);
    setPalette(palette);
}
void MyWidget::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setPen(Qt::darkGreen);
    painter.drawRect(1, 2, 6, 4);
    painter.setPen(Qt::darkGray);
    painter.drawLine(2, 8, 6, 2);
}
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MyWidget widget;
    widget.show();
    return app.exec();
}


svg viewer

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef SVGVIEW_H
#define SVGVIEW_H
#include <QGraphicsView>
QT_BEGIN_NAMESPACE
class QWheelEvent;
class QPaintEvent;
class QFile;
QT_END_NAMESPACE
class SvgView : public QGraphicsView
{
    Q_OBJECT
public:
    enum RendererType { Native, OpenGL, Image };
    SvgView(QWidget *parent = 0);
    void openFile(const QFile &file);
    void setRenderer(RendererType type = Native);
    void drawBackground(QPainter *p, const QRectF &rect);
public slots:
    void setHighQualityAntialiasing(bool highQualityAntialiasing);
    void setViewBackground(bool enable);
    void setViewOutline(bool enable);
protected:
    void wheelEvent(QWheelEvent *event);
    void paintEvent(QPaintEvent *event);
private:
    RendererType m_renderer;
    QGraphicsItem *m_svgItem;
    QGraphicsRectItem *m_backgroundItem;
    QGraphicsRectItem *m_outlineItem;
    QImage m_image;
};
#end



#include "svgview.h"
#include <QFile>
#include <QWheelEvent>
#include <QMouseEvent>
#include <QGraphicsRectItem>
#include <QGraphicsSvgItem>
#include <QPaintEvent>
#include <qmath.h>
#ifndef QT_NO_OPENGL
#include <QGLWidget>
#endif
SvgView::SvgView(QWidget *parent)
    : QGraphicsView(parent)
    , m_renderer(Native)
    , m_svgItem(0)
    , m_backgroundItem(0)
    , m_outlineItem(0)
{
    setScene(new QGraphicsScene(this));
    setTransformationAnchor(AnchorUnderMouse);
    setDragMode(ScrollHandDrag);
    // Prepare background check-board pattern
    QPixmap tilePixmap(64, 64);
    tilePixmap.fill(Qt::white);
    QPainter tilePainter(&tilePixmap);
    QColor color(220, 220, 220);
    tilePainter.fillRect(0, 0, 32, 32, color);
    tilePainter.fillRect(32, 32, 32, 32, color);
    tilePainter.end();
    setBackgroundBrush(tilePixmap);
}
void SvgView::drawBackground(QPainter *p, const QRectF &)
{
    p->save();
    p->resetTransform();
    p->drawTiledPixmap(viewport()->rect(), backgroundBrush().texture());
    p->restore();
}
void SvgView::openFile(const QFile &file)
{
    if (!file.exists())
        return;
    QGraphicsScene *s = scene();
    bool drawBackground = (m_backgroundItem ? m_backgroundItem->isVisible() : false);
    bool drawOutline = (m_outlineItem ? m_outlineItem->isVisible() : true);
    s->clear();
    resetTransform();
    m_svgItem = new QGraphicsSvgItem(file.fileName());
    m_svgItem->setFlags(QGraphicsItem::ItemClipsToShape);
    m_svgItem->setCacheMode(QGraphicsItem::NoCache);
    m_svgItem->setZValue(0);
    m_backgroundItem = new QGraphicsRectItem(m_svgItem->boundingRect());
    m_backgroundItem->setBrush(Qt::white);
    m_backgroundItem->setPen(Qt::NoPen);
    m_backgroundItem->setVisible(drawBackground);
    m_backgroundItem->setZValue(-1);
    m_outlineItem = new QGraphicsRectItem(m_svgItem->boundingRect());
    QPen outline(Qt::black, 2, Qt::DashLine);
    outline.setCosmetic(true);
    m_outlineItem->setPen(outline);
    m_outlineItem->setBrush(Qt::NoBrush);
    m_outlineItem->setVisible(drawOutline);
    m_outlineItem->setZValue(1);
    s->addItem(m_backgroundItem);
    s->addItem(m_svgItem);
    s->addItem(m_outlineItem);
    s->setSceneRect(m_outlineItem->boundingRect().adjusted(-10, -10, 10, 10));
}
void SvgView::setRenderer(RendererType type)
{
    m_renderer = type;
    if (m_renderer == OpenGL) {
#ifndef QT_NO_OPENGL
        setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers)));
#endif
    } else {
        setViewport(new QWidget);
    }
}
void SvgView::setHighQualityAntialiasing(bool highQualityAntialiasing)
{
#ifndef QT_NO_OPENGL
    setRenderHint(QPainter::HighQualityAntialiasing, highQualityAntialiasing);
#else
    Q_UNUSED(highQualityAntialiasing);
#endif
}
void SvgView::setViewBackground(bool enable)
{
    if (!m_backgroundItem)
          return;
    m_backgroundItem->setVisible(enable);
}
void SvgView::setViewOutline(bool enable)
{
    if (!m_outlineItem)
        return;
    m_outlineItem->setVisible(enable);
}
void SvgView::paintEvent(QPaintEvent *event)
{
    if (m_renderer == Image) {
        if (m_image.size() != viewport()->size()) {
            m_image = QImage(viewport()->size(), QImage::Format_ARGB32_Premultiplied);
        }
        QPainter imagePainter(&m_image);
        QGraphicsView::render(&imagePainter);
        imagePainter.end();
        QPainter p(viewport());
        p.drawImage(0, 0, m_image);
    } else {
        QGraphicsView::paintEvent(event);
    }
}
void SvgView::wheelEvent(QWheelEvent *event)
{
    qreal factor = qPow(1.2, event->delta() / 240.0);
    scale(factor, factor);
    event->accept();
}




#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QString>
class SvgView;
QT_BEGIN_NAMESPACE
class QAction;
class QGraphicsView;
class QGraphicsScene;
class QGraphicsRectItem;
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow();
public slots:
    void openFile(const QString &path = QString());
    void setRenderer(QAction *action);
private:
    QAction *m_nativeAction;
    QAction *m_glAction;
    QAction *m_imageAction;
    QAction *m_highQualityAntialiasingAction;
    QAction *m_backgroundAction;
    QAction *m_outlineAction;
    SvgView *m_view;
    QString m_currentPath;
};
#endif



#include "mainwindow.h"
#include <QtGui>
#include "svgview.h"
MainWindow::MainWindow()
    : QMainWindow()
    , m_view(new SvgView)
{
    QMenu *fileMenu = new QMenu(tr("&File"), this);
    QAction *openAction = fileMenu->addAction(tr("&Open..."));
    openAction->setShortcut(QKeySequence(tr("Ctrl+O")));
    QAction *quitAction = fileMenu->addAction(tr("E&xit"));
    quitAction->setShortcut(QKeySequence(tr("Ctrl+Q")));
    menuBar()->addMenu(fileMenu);
    QMenu *viewMenu = new QMenu(tr("&View"), this);
    m_backgroundAction = viewMenu->addAction(tr("&Background"));
    m_backgroundAction->setEnabled(false);
    m_backgroundAction->setCheckable(true);
    m_backgroundAction->setChecked(false);
    connect(m_backgroundAction, SIGNAL(toggled(bool)), m_view, SLOT(setViewBackground(bool)));
    m_outlineAction = viewMenu->addAction(tr("&Outline"));
    m_outlineAction->setEnabled(false);
    m_outlineAction->setCheckable(true);
    m_outlineAction->setChecked(true);
    connect(m_outlineAction, SIGNAL(toggled(bool)), m_view, SLOT(setViewOutline(bool)));
    menuBar()->addMenu(viewMenu);
    QMenu *rendererMenu = new QMenu(tr("&Renderer"), this);
    m_nativeAction = rendererMenu->addAction(tr("&Native"));
    m_nativeAction->setCheckable(true);
    m_nativeAction->setChecked(true);
#ifndef QT_NO_OPENGL
    m_glAction = rendererMenu->addAction(tr("&OpenGL"));
    m_glAction->setCheckable(true);
#endif
    m_imageAction = rendererMenu->addAction(tr("&Image"));
    m_imageAction->setCheckable(true);
#ifndef QT_NO_OPENGL
    rendererMenu->addSeparator();
    m_highQualityAntialiasingAction = rendererMenu->addAction(tr("&High Quality Antialiasing"));
    m_highQualityAntialiasingAction->setEnabled(false);
    m_highQualityAntialiasingAction->setCheckable(true);
    m_highQualityAntialiasingAction->setChecked(false);
    connect(m_highQualityAntialiasingAction, SIGNAL(toggled(bool)), m_view, SLOT(setHighQualityAntialiasing(bool)));
#endif
    QActionGroup *rendererGroup = new QActionGroup(this);
    rendererGroup->addAction(m_nativeAction);
#ifndef QT_NO_OPENGL
    rendererGroup->addAction(m_glAction);
#endif
    rendererGroup->addAction(m_imageAction);
    menuBar()->addMenu(rendererMenu);
    connect(openAction, SIGNAL(triggered()), this, SLOT(openFile()));
    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
    connect(rendererGroup, SIGNAL(triggered(QAction *)),
            this, SLOT(setRenderer(QAction *)));
    setCentralWidget(m_view);
    setWindowTitle(tr("SVG Viewer"));
}
void MainWindow::openFile(const QString &path)
{
    QString fileName;
    if (path.isNull())
        fileName = QFileDialog::getOpenFileName(this, tr("Open SVG File"),
                m_currentPath, "SVG files (*.svg *.svgz *.svg.gz)");
    else
        fileName = path;
    if (!fileName.isEmpty()) {
        QFile file(fileName);
        if (!file.exists()) {
            QMessageBox::critical(this, tr("Open SVG File"),
                           QString("Could not open file "%1".").arg(fileName));
            m_outlineAction->setEnabled(false);
            m_backgroundAction->setEnabled(false);
            return;
        }
        m_view->openFile(file);
        if (!fileName.startsWith(":/")) {
            m_currentPath = fileName;
            setWindowTitle(tr("%1 - SVGViewer").arg(m_currentPath));
        }
        m_outlineAction->setEnabled(true);
        m_backgroundAction->setEnabled(true);
        resize(m_view->sizeHint() + QSize(80, 80 + menuBar()->height()));
    }
}
void MainWindow::setRenderer(QAction *action)
{
#ifndef QT_NO_OPENGL
    m_highQualityAntialiasingAction->setEnabled(false);
#endif
    if (action == m_nativeAction)
        m_view->setRenderer(SvgView::Native);
#ifndef QT_NO_OPENGL
    else if (action == m_glAction) {
        m_highQualityAntialiasingAction->setEnabled(true);
        m_view->setRenderer(SvgView::OpenGL);
    }
#endif
    else if (action == m_imageAction) {
        m_view->setRenderer(SvgView::Image);
    }
}



#include <QApplication>
#include <QString>
#ifndef QT_NO_OPENGL
#include <QGLFormat>
#endif
#include "mainwindow.h"
int main(int argc, char **argv)
{
    Q_INIT_RESOURCE(svgviewer);
    QApplication app(argc, argv);
    MainWindow window;
    if (argc == 2)
        window.openFile(argv[1]);
    else
        window.openFile(":/files/bubbles.svg");
    window.show();
    return app.exec();
}


Transformation demo

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef RENDERAREA_H
#define RENDERAREA_H
#include <QFont>
#include <QList>
#include <QPainterPath>
#include <QRect>
#include <QWidget>
QT_BEGIN_NAMESPACE
class QPaintEvent;
QT_END_NAMESPACE

enum Operation { NoTransformation, Translate, Rotate, Scale };

class RenderArea : public QWidget
{
    Q_OBJECT
public:
    RenderArea(QWidget *parent = 0);
    void setOperations(const QList<Operation> &operations);
    void setShape(const QPainterPath &shape);
    QSize minimumSizeHint() const;
    QSize sizeHint() const;
protected:
    void paintEvent(QPaintEvent *event);

private:
    void drawCoordinates(QPainter &painter);
    void drawOutline(QPainter &painter);
    void drawShape(QPainter &painter);
    void transformPainter(QPainter &painter);
    QList<Operation> operations;
    QPainterPath shape;
    QRect xBoundingRect;
    QRect yBoundingRect;
};

#endif



#include <QtGui>
#include "renderarea.h"

RenderArea::RenderArea(QWidget *parent)
    : QWidget(parent)
{
    QFont newFont = font();
    newFont.setPixelSize(12);
    setFont(newFont);
    QFontMetrics fontMetrics(newFont);
    xBoundingRect = fontMetrics.boundingRect(tr("x"));
    yBoundingRect = fontMetrics.boundingRect(tr("y"));
}

void RenderArea::setOperations(const QList<Operation> &operations)
{
    this->operations = operations;
    update();
}

void RenderArea::setShape(const QPainterPath &shape)
{
    this->shape = shape;
    update();
}

QSize RenderArea::minimumSizeHint() const
{
    return QSize(182, 182);
}

QSize RenderArea::sizeHint() const
{
    return QSize(232, 232);
}

void RenderArea::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.fillRect(event->rect(), QBrush(Qt::white));
    painter.translate(66, 66);

    painter.save();
    transformPainter(painter);
    drawShape(painter);
    painter.restore();

    drawOutline(painter);

    transformPainter(painter);
    drawCoordinates(painter);
}

void RenderArea::drawCoordinates(QPainter &painter)
{
    painter.setPen(Qt::red);
    painter.drawLine(0, 0, 50, 0);
    painter.drawLine(48, -2, 50, 0);
    painter.drawLine(48, 2, 50, 0);
    painter.drawText(60 - xBoundingRect.width() / 2,
                     0 + xBoundingRect.height() / 2, tr("x"));
    painter.drawLine(0, 0, 0, 50);
    painter.drawLine(-2, 48, 0, 50);
    painter.drawLine(2, 48, 0, 50);
    painter.drawText(0 - yBoundingRect.width() / 2,
                     60 + yBoundingRect.height() / 2, tr("y"));
}

void RenderArea::drawOutline(QPainter &painter)
{
    painter.setPen(Qt::darkGreen);
    painter.setPen(Qt::DashLine);
    painter.setBrush(Qt::NoBrush);
    painter.drawRect(0, 0, 100, 100);
}

void RenderArea::drawShape(QPainter &painter)
{
    painter.fillPath(shape, Qt::blue);
}

void RenderArea::transformPainter(QPainter &painter)
{
    for (int i = 0; i < operations.size(); ++i) {
        switch (operations[i]) {
        case Translate:
            painter.translate(50, 50);
            break;
        case Scale:
            painter.scale(0.75, 0.75);
            break;
        case Rotate:
            painter.rotate(60);
            break;
        case NoTransformation:
        default:
            ;
        }
    }
}



#ifndef WINDOW_H
#define WINDOW_H
#include <QList>
#include <QPainterPath>
#include <QWidget>
#include "renderarea.h"
QT_BEGIN_NAMESPACE
class QComboBox;
QT_END_NAMESPACE

class Window : public QWidget
{
    Q_OBJECT
public:
    Window();
public slots:
    void operationChanged();
    void shapeSelected(int index);

private:
    void setupShapes();
    enum { NumTransformedAreas = 3 };
    RenderArea *originalRenderArea;
    RenderArea *transformedRenderAreas[NumTransformedAreas];
    QComboBox *shapeComboBox;
    QComboBox *operationComboBoxes[NumTransformedAreas];
    QList<QPainterPath> shapes;
};

#endif



#include <QtGui>
#include "window.h"

Window::Window()
{
    originalRenderArea = new RenderArea;
    shapeComboBox = new QComboBox;
    shapeComboBox->addItem(tr("Clock"));
    shapeComboBox->addItem(tr("House"));
    shapeComboBox->addItem(tr("Text"));
    shapeComboBox->addItem(tr("Truck"));
    QGridLayout *layout = new QGridLayout;
    layout->addWidget(originalRenderArea, 0, 0);
    layout->addWidget(shapeComboBox, 1, 0);

    for (int i = 0; i < NumTransformedAreas; ++i) {
        transformedRenderAreas[i] = new RenderArea;
        operationComboBoxes[i] = new QComboBox;
        operationComboBoxes[i]->addItem(tr("No transformation"));
        operationComboBoxes[i]->addItem(tr("Rotate by 60\xB0"));
        operationComboBoxes[i]->addItem(tr("Scale to 75%"));
        operationComboBoxes[i]->addItem(tr("Translate by (50, 50)"));
        connect(operationComboBoxes[i], SIGNAL(activated(int)),
                this, SLOT(operationChanged()));
        layout->addWidget(transformedRenderAreas[i], 0, i + 1);
        layout->addWidget(operationComboBoxes[i], 1, i + 1);
    }

    setLayout(layout);
    setupShapes();
    shapeSelected(0);
    setWindowTitle(tr("Transformations"));
}

void Window::setupShapes()
{
    QPainterPath truck;
    truck.setFillRule(Qt::WindingFill);
    truck.moveTo(0.0, 87.0);
    truck.lineTo(0.0, 60.0);
    truck.lineTo(10.0, 60.0);
    truck.lineTo(35.0, 35.0);
    truck.lineTo(100.0, 35.0);
    truck.lineTo(100.0, 87.0);
    truck.lineTo(0.0, 87.0);
    truck.moveTo(17.0, 60.0);
    truck.lineTo(55.0, 60.0);
    truck.lineTo(55.0, 40.0);
    truck.lineTo(37.0, 40.0);
    truck.lineTo(17.0, 60.0);
    truck.addEllipse(17.0, 75.0, 25.0, 25.0);
    truck.addEllipse(63.0, 75.0, 25.0, 25.0);

    QPainterPath clock;
    clock.addEllipse(-50.0, -50.0, 100.0, 100.0);
    clock.addEllipse(-48.0, -48.0, 96.0, 96.0);
    clock.moveTo(0.0, 0.0);
    clock.lineTo(-2.0, -2.0);
    clock.lineTo(0.0, -42.0);
    clock.lineTo(2.0, -2.0);
    clock.lineTo(0.0, 0.0);
    clock.moveTo(0.0, 0.0);
    clock.lineTo(2.732, -0.732);
    clock.lineTo(24.495, 14.142);
    clock.lineTo(0.732, 2.732);
    clock.lineTo(0.0, 0.0);

    QPainterPath house;
    house.moveTo(-45.0, -20.0);
    house.lineTo(0.0, -45.0);
    house.lineTo(45.0, -20.0);
    house.lineTo(45.0, 45.0);
    house.lineTo(-45.0, 45.0);
    house.lineTo(-45.0, -20.0);
    house.addRect(15.0, 5.0, 20.0, 35.0);
    house.addRect(-35.0, -15.0, 25.0, 25.0);

    QPainterPath text;
    QFont font;
    font.setPixelSize(50);
    QRect fontBoundingRect = QFontMetrics(font).boundingRect(tr("Qt"));
    text.addText(-QPointF(fontBoundingRect.center()), font, tr("Qt"));

    shapes.append(clock);
    shapes.append(house);
    shapes.append(text);
    shapes.append(truck);
    connect(shapeComboBox, SIGNAL(activated(int)),
            this, SLOT(shapeSelected(int)));
}

void Window::operationChanged()
{
    static const Operation operationTable[] = {
        NoTransformation, Rotate, Scale, Translate
    };
    QList<Operation> operations;
    for (int i = 0; i < NumTransformedAreas; ++i) {
        int index = operationComboBoxes[i]->currentIndex();
        operations.append(operationTable[index]);
        transformedRenderAreas[i]->setOperations(operations);
    }
}

void Window::shapeSelected(int index)
{
    QPainterPath shape = shapes[index];
    originalRenderArea->setShape(shape);
    for (int i = 0; i < NumTransformedAreas; ++i)
        transformedRenderAreas[i]->setShape(shape);
}



#include <QApplication>
#include "window.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Window window;
    window.show();
    return app.exec();
}


Transformed Painter

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
#include <cmath>
class SimpleTransformation : public QWidget
{
    void paintEvent(QPaintEvent *);
};

void SimpleTransformation::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setPen(QPen(Qt::blue, 1, Qt::DashLine));
    painter.drawRect(0, 0, 100, 100);
    painter.rotate(45);
    painter.setFont(QFont("Helvetica", 24));
    painter.setPen(QPen(Qt::black, 1));
    painter.drawText(20, 10, "QTransform");
}

class CombinedTransformation : public QWidget
{
    void paintEvent(QPaintEvent *);
};

void CombinedTransformation::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setPen(QPen(Qt::blue, 1, Qt::DashLine));
    painter.drawRect(0, 0, 100, 100);
    QTransform transform;
    transform.translate(50, 50);
    transform.rotate(45);
    transform.scale(0.5, 1.0);
    painter.setTransform(transform);
    painter.setFont(QFont("Helvetica", 24));
    painter.setPen(QPen(Qt::black, 1));
    painter.drawText(20, 10, "QTransform");
}

class BasicOperations : public QWidget
{
    void paintEvent(QPaintEvent *);
};

void BasicOperations::paintEvent(QPaintEvent *)
{
    double pi = 3.14;
    double a    = pi/180 * 45.0;
    double sina = sin(a);
    double cosa = cos(a);
    QTransform translationTransform(1, 0, 0, 1, 50.0, 50.0);
    QTransform rotationTransform(cosa, sina, -sina, cosa, 0, 0);
    QTransform scalingTransform(0.5, 0, 0, 1.0, 0, 0);
    QTransform transform;
    transform = scalingTransform * rotationTransform * translationTransform;
    QPainter painter(this);
    painter.setPen(QPen(Qt::blue, 1, Qt::DashLine));
    painter.drawRect(0, 0, 100, 100);
    painter.setTransform(transform);
    painter.setFont(QFont("Helvetica", 24));
    painter.setPen(QPen(Qt::black, 1));
    painter.drawText(20, 10, "QTransform");
}

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    QWidget widget;
    SimpleTransformation *simpleWidget = new SimpleTransformation;
    CombinedTransformation *combinedWidget = new CombinedTransformation;
    BasicOperations *basicWidget = new BasicOperations;
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(simpleWidget);
    layout->addWidget(combinedWidget);
    layout->addWidget(basicWidget);
    widget.setLayout(layout);
    widget.show();
    widget.resize(130, 350);
    return app.exec();
}


Use QPainter to draw arc

  
Foundations of Qt Development\Chapter07\circles\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPixmap>
#include <QPainter>
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  QPixmap pixmap( 200, 190 );
  pixmap.fill( Qt::white );
  QPainter painter( &pixmap );
  painter.setRenderHint( QPainter::Antialiasing );
  painter.setPen( Qt::black );
    
  painter.drawEllipse( 10, 10, 10, 80 );
  painter.drawEllipse( 30, 10, 20, 80 );
  painter.drawEllipse( 60, 10, 40, 80 );
  painter.drawEllipse( QRect( 110, 10, 80, 80 ) );
  painter.drawArc( 10, 100, 10, 80, 30*16, 240*16 );
  painter.drawArc( 30, 100, 20, 80, 45*16, 200*16 );
  painter.drawArc( 60, 100, 40, 80, 60*16, 160*16 );
  painter.drawArc( QRect( 110, 100, 80, 80 ), 75*16, 120*16 );
  pixmap.save( "circles.png" );
  return 0;
}


User-draw table

  
Foundations of Qt Development\Chapter05\editdelegate\bardelegate.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QPainter>
#include <QSlider>
#include <QModelIndex>
#include "bardelegate.h"
BarDelegate::BarDelegate( QObject *parent ) : QAbstractItemDelegate( parent ) { }
void BarDelegate::paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
  if( option.state & QStyle::State_Selected )
    painter->fillRect( option.rect, option.palette.highlight() );
  int value = index.model()->data( index, Qt::DisplayRole ).toInt();
  double factor = double(value)/100.0;
  
  painter->save();
  if( factor > 1 )
  {
    painter->setBrush( Qt::red );
    factor = 1;
  }
  else
    painter->setBrush( QColor( 0, int(factor*255), 255-int(factor*255) ) );
  painter->setPen( Qt::black );
  painter->drawRect( option.rect.x()+2, option.rect.y()+2, int(factor*(option.rect.width()-5)), option.rect.height()-5 );
  painter->restore();
}
QSize BarDelegate::sizeHint( const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
  return QSize( 45, 15 ); 
}
QWidget *BarDelegate::createEditor( QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
  QSlider *slider = new QSlider( parent );
  
  slider->setAutoFillBackground( true );
  slider->setOrientation( Qt::Horizontal );
  slider->setRange( 0, 100 );
  slider->installEventFilter( const_cast<BarDelegate*>(this) );
  
  return slider;
}
void BarDelegate::updateEditorGeometry( QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
  editor->setGeometry( option.rect );
}
void BarDelegate::setEditorData( QWidget *editor, const QModelIndex &index ) const
{
  int value = index.model()->data( index, Qt::DisplayRole ).toInt();
  static_cast<QSlider*>( editor )->setValue( value );
}
void BarDelegate::setModelData( QWidget *editor, QAbstractItemModel *model, const QModelIndex &index ) const
{
  model->setData( index, static_cast<QSlider*>( editor )->value() );
}


Foundations of Qt Development\Chapter05\editdelegate\bardelegate.h
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#ifndef BARDELEGATE_H
#define BARDELEGATE_H
#include <QAbstractItemDelegate>
class BarDelegate : public QAbstractItemDelegate
{
public:
  BarDelegate( QObject *parent = 0 );
  void paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const;
  QSize sizeHint( const QStyleOptionViewItem &option, const QModelIndex &index ) const;
  QWidget *createEditor( QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index ) const;
  void setEditorData( QWidget *editor, const QModelIndex &index ) const;
  void setModelData( QWidget *editor, QAbstractItemModel *model, const QModelIndex &index ) const;
  void updateEditorGeometry( QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index ) const;
};
#endif // BARDELEGATE_H

Foundations of Qt Development\Chapter05\editdelegate\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QTableView>
#include <QStandardItemModel>
#include "bardelegate.h"
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  QTableView table;
  QStandardItemModel model( 10, 2 ); 
  for( int r=0; r<10; ++r )
  {
    QStandardItem *item = new QStandardItem( QString("Row %1").arg(r+1) );
    item->setEditable( false ); 
    model.setItem( r, 0, item );
    
    model.setItem( r, 1, new QStandardItem( QString::number((r*30)%100 )) );  
  }
  table.setModel( &model );
  
  BarDelegate delegate;
  table.setItemDelegateForColumn( 1, &delegate );
  table.show();
  
  return app.exec();
}


Using QPainter to draw ellipse

  
Foundations of Qt Development\Chapter07\circles\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPixmap>
#include <QPainter>
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  QPixmap pixmap( 200, 190 );
  pixmap.fill( Qt::white );
  QPainter painter( &pixmap );
  painter.setRenderHint( QPainter::Antialiasing );
  painter.setPen( Qt::black );
    
  painter.drawEllipse( 10, 10, 10, 80 );
  painter.drawEllipse( 30, 10, 20, 80 );
  painter.drawEllipse( 60, 10, 40, 80 );
  painter.drawEllipse( QRect( 110, 10, 80, 80 ) );
  painter.drawArc( 10, 100, 10, 80, 30*16, 240*16 );
  painter.drawArc( 30, 100, 20, 80, 45*16, 200*16 );
  painter.drawArc( 60, 100, 40, 80, 60*16, 160*16 );
  painter.drawArc( QRect( 110, 100, 80, 80 ), 75*16, 120*16 );
  pixmap.save( "circles.png" );
  return 0;
}