Mega Code Archive
Using QSlider to control custom component
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Foundations of Qt Development\Chapter06\circlebar\circlebar.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
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <QPaintEvent>
#include <QWheelEvent>
#include <QPainter>
#include "circlebar.h"
CircleBar::CircleBar( int value, QWidget *parent ) : QWidget( parent )
{
m_value = value;
QSizePolicy policy( QSizePolicy::Preferred, QSizePolicy::Preferred );
policy.setHeightForWidth( true );
setSizePolicy( policy );
}
int CircleBar::heightForWidth( int width ) const
{
return width;
}
QSize CircleBar::sizeHint() const
{
return QSize( 100, 100 );
}
int CircleBar::value() const
{
return m_value;
}
void CircleBar::setValue( int value )
{
if( value < 0 )
value = 0;
if( value > 100 )
value = 100;
if( m_value == value )
return;
m_value = value;
update();
emit valueChanged( m_value );
}
void CircleBar::paintEvent( QPaintEvent *event )
{
int radius = width()/2;
double factor = m_value/100.0;
QPainter p( this );
p.setPen( Qt::black );
p.drawEllipse( 0, 0, width()-1, width()-1 );
p.setBrush( Qt::black );
p.drawEllipse( int(radius*(1.0-factor)), int(radius*(1.0-factor)), int((width()-1)*factor)+1, int((width()-1)*factor)+1 );
}
void CircleBar::wheelEvent( QWheelEvent *event )
{
event->accept();
setValue( value() + event->delta()/20 );
}
Foundations of Qt Development\Chapter06\circlebar\circlebar.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 CIRCLEBAR_H
#define CIRCLEBAR_H
#include <QWidget>
class CircleBar : public QWidget
{
Q_OBJECT
public:
CircleBar( int value = 0, QWidget *parent = 0 );
int value() const;
int heightForWidth( int ) const;
QSize sizeHint() const;
public slots:
void setValue( int );
signals:
void valueChanged( int );
protected:
void paintEvent( QPaintEvent* );
void wheelEvent( QWheelEvent* );
private:
int m_value;
};
#endif // CIRCLEBAR_H
Foundations of Qt Development\Chapter06\circlebar\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
* * 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 <QSlider>
#include <QVBoxLayout>
#include "circlebar.h"
int main( int argc, char **argv )
{
QApplication app( argc, argv );
QWidget base;
QVBoxLayout layout( &base );
CircleBar bar;
QSlider slider( Qt::Horizontal );
layout.addWidget( &bar );
layout.addWidget( &slider );
QObject::connect( &slider, SIGNAL(valueChanged(int)), &bar, SLOT(setValue(int)) );
QObject::connect( &bar, SIGNAL(valueChanged(int)), &slider, SLOT(setValue(int)) );
base.show();
return app.exec();
}
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