C++/Qt/QPainter

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Circle Widget with paint

<source lang="cpp">

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.
*
*/
  1. include "circlewidget.h"
  2. include <QPainter>
  3. include <QMouseEvent>
  4. 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.
*
*/
  1. ifndef CIRCLEWIDGET_H
  2. define CIRCLEWIDGET_H
  3. 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;

};

  1. 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.
*
*/
  1. include <QApplication>
  2. include "circlewidget.h"

int main( int argc, char **argv ) {

 QApplication app( argc, argv );
 
 CircleWidget widget;
 widget.show();
 
 return app.exec();

}


 </source>


Draws a filled-in circle

<source lang="cpp">

  1. 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();

}


 </source>


Draw text

<source lang="cpp"> 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.
*
*/
  1. include <QApplication>
  2. include <QPixmap>
  3. include <QPainter>
  4. 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( "

A QTextDocument can be used to present formatted text " "in a nice way.

" "

It can be formatted " "in different ways.

" "

The text can be really long and contain many " "paragraphs. It is properly wrapped and such...

" );
 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;

}


 </source>


Linear Gradient

<source lang="cpp">

  1. 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();

}


 </source>


Matrix based translation

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. include <QtGui>
  2. 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();

}


 </source>


Painter

<source lang="cpp">

  1. 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();

}


 </source>


Painter path

<source lang="cpp">

/****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. 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();

}


 </source>


Paint picture

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. 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
   }

}


 </source>


Paint rectangle

<source lang="cpp"> 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.
*
*/
  1. include <QPainter>
  2. include <QModelIndex>
  3. 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.
*
*/
  1. ifndef BARDELEGATE_H
  2. define BARDELEGATE_H
  3. 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;

};

  1. 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.
*
*/
  1. include <QApplication>
  2. include <QTableView>
  3. include <QStandardItemModel>
  4. 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();

}


 </source>


QConicalGradient

<source lang="cpp">

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.
*
*/
  1. include <QApplication>
  2. include <QPainter>
  3. include <QBrush>
  4. 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;

}


 </source>


QLinearGradient and QPainter

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. ifndef PAINTWIDGET_H
  2. define PAINTWIDGET_H
  3. include <QWidget>

class QPaintEvent; class PaintWidget : public QWidget {

   Q_OBJECT

public:

   PaintWidget(QWidget *parent = 0);

protected:

   void paintEvent(QPaintEvent *event);

};

  1. endif


  1. include <QtGui>
  2. 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();

}


  1. include <QtGui>
  2. include "paintwidget.h"

int main(int argc, char *argv[]) {

   QApplication app(argc, argv);
   PaintWidget window;
   window.show();
   return app.exec();

}


 </source>


Renderer pattern

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. ifndef CLIPWINDOW_H
  2. define CLIPWINDOW_H
  3. 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;

};

  1. endif




  1. include <QtGui>
  2. 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()));

}



  1. include <QApplication>
  2. 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();

}


 </source>


Set pen and brush for QPainter

<source lang="cpp"> 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.
*
*/
  1. include <QApplication>
  2. include <QPixmap>
  3. 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;

}


 </source>


Set render hint to QPainter::Antialiasing

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. 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();

}


 </source>


svg viewer

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. ifndef SVGVIEW_H
  2. define SVGVIEW_H
  3. 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;

};

  1. end


  1. include "svgview.h"
  2. include <QFile>
  3. include <QWheelEvent>
  4. include <QMouseEvent>
  5. include <QGraphicsRectItem>
  6. include <QGraphicsSvgItem>
  7. include <QPaintEvent>
  8. include <qmath.h>
  9. ifndef QT_NO_OPENGL
  10. include <QGLWidget>
  11. 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) {
  1. ifndef QT_NO_OPENGL
       setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers)));
  1. endif
   } else {
       setViewport(new QWidget);
   }

} void SvgView::setHighQualityAntialiasing(bool highQualityAntialiasing) {

  1. ifndef QT_NO_OPENGL
   setRenderHint(QPainter::HighQualityAntialiasing, highQualityAntialiasing);
  1. else
   Q_UNUSED(highQualityAntialiasing);
  1. 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();

}



  1. ifndef MAINWINDOW_H
  2. define MAINWINDOW_H
  3. include <QMainWindow>
  4. 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;

};

  1. endif


  1. include "mainwindow.h"
  2. include <QtGui>
  3. 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);
  1. ifndef QT_NO_OPENGL
   m_glAction = rendererMenu->addAction(tr("&OpenGL"));
   m_glAction->setCheckable(true);
  1. endif
   m_imageAction = rendererMenu->addAction(tr("&Image"));
   m_imageAction->setCheckable(true);
  1. 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)));
  1. endif
   QActionGroup *rendererGroup = new QActionGroup(this);
   rendererGroup->addAction(m_nativeAction);
  1. ifndef QT_NO_OPENGL
   rendererGroup->addAction(m_glAction);
  1. 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) {

  1. ifndef QT_NO_OPENGL
   m_highQualityAntialiasingAction->setEnabled(false);
  1. endif
   if (action == m_nativeAction)
       m_view->setRenderer(SvgView::Native);
  1. ifndef QT_NO_OPENGL
   else if (action == m_glAction) {
       m_highQualityAntialiasingAction->setEnabled(true);
       m_view->setRenderer(SvgView::OpenGL);
   }
  1. endif
   else if (action == m_imageAction) {
       m_view->setRenderer(SvgView::Image);
   }

}


  1. include <QApplication>
  2. include <QString>
  3. ifndef QT_NO_OPENGL
  4. include <QGLFormat>
  5. endif
  6. 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();

}


 </source>


Transformation demo

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. ifndef RENDERAREA_H
  2. define RENDERAREA_H
  3. include <QFont>
  4. include <QList>
  5. include <QPainterPath>
  6. include <QRect>
  7. 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;

};

  1. endif


  1. include <QtGui>
  2. 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:
           ;
       }
   }

}


  1. ifndef WINDOW_H
  2. define WINDOW_H
  3. include <QList>
  4. include <QPainterPath>
  5. include <QWidget>
  6. 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;

};

  1. endif


  1. include <QtGui>
  2. 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);

}


  1. include <QApplication>
  2. include "window.h"

int main(int argc, char *argv[]) {

   QApplication app(argc, argv);
   Window window;
   window.show();
   return app.exec();

}


 </source>


Transformed Painter

<source lang="cpp"> /****************************************************************************

    • 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. include <QtGui>
  2. 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();

}


 </source>


Use QPainter to draw arc

<source lang="cpp"> 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.
*
*/
  1. include <QApplication>
  2. include <QPixmap>
  3. 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;

}


 </source>


User-draw table

<source lang="cpp"> 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.
*
*/
  1. include <QPainter>
  2. include <QSlider>
  3. include <QModelIndex>
  4. 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.
*
*/
  1. ifndef BARDELEGATE_H
  2. define BARDELEGATE_H
  3. 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;

};

  1. 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.
*
*/
  1. include <QApplication>
  2. include <QTableView>
  3. include <QStandardItemModel>
  4. 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();

}


 </source>


Using QPainter to draw ellipse

<source lang="cpp"> 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.
*
*/
  1. include <QApplication>
  2. include <QPixmap>
  3. 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;

}


 </source>