Warning, file /graphics/kdiagram/examples/demo/colorslider.cpp was not indexed or was modified since last indexation (in which case cross-reference links may be missing, inaccurate or erroneous).

 /**
  * Copyright (C) 2001-2015 Klaralvdalens Datakonsult AB.  All rights reserved.
  *
  * This file is part of the KD Chart library.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 #include "colorslider.h"
 
 #include <QPaintEvent>
 #include <QPainter>
 #include <QMouseEvent>
 
 #include <QDebug>
 
 class ColorSlider::Private
 {
 public:
     Private( ColorSlider *q );
     void drawSliderMarker( QPainter *painter );
     QColor m_startColor;
     QColor m_endColor;
     bool m_dragging;
     ColorSlider *qq;
 };
 
 ColorSlider::Private::Private( ColorSlider *q )
     : m_dragging( false )
     , qq( q )
 {
 
 }
 
 void ColorSlider::Private::drawSliderMarker( QPainter *painter )
 {
     QVector< QPointF > points; points << QPointF( -0.5, 0 ) << QPointF( 0.0, 0.5 ) << QPointF( 0.5, 0 );
     QPolygonF triangle( points );
     painter->drawPolygon( triangle );
 }
 
 ColorSlider::ColorSlider( QWidget *parent )
     : QAbstractSlider( parent )
     , d( new Private( this ) )
 {
     setSizePolicy( QSizePolicy( QSizePolicy::Minimum ,QSizePolicy::Fixed) );
     setMinimum( 0 );
     setMaximum( 255 );
     setValue( 25 );
 }
 
 ColorSlider::~ColorSlider()
 {
     delete d;
 }
 
 QColor ColorSlider::startColor() const
 {
     return d->m_startColor;
 }
 void ColorSlider::setStartColor( const QColor &color )
 {
     if ( d->m_startColor != color )
     {
         d->m_startColor = color;
         Q_EMIT startColorChanged();
         update();
     }
 }
 QColor ColorSlider::endColor() const
 {
     return d->m_endColor;
 }
 void ColorSlider::setEndColor( const QColor &color )
 {
     if ( d->m_endColor != color )
     {
         d->m_endColor = color;
         Q_EMIT startColorChanged();
         update();
     }
 }
 
 void ColorSlider::paintEvent( QPaintEvent *event )
 {
     QAbstractSlider::paintEvent( event );
     const double percentage = value() / ( double )( maximum() - minimum() );
     QPainter painter( this );
     QLinearGradient gradient;
     gradient.setStart( 0, 0 );
     gradient.setFinalStop( 1, 0 );
     gradient.setCoordinateMode( QGradient::ObjectBoundingMode );
     gradient.setColorAt( 0, d->m_startColor );
     gradient.setColorAt( 1, d->m_endColor );
     painter.setBrush( gradient );
     painter.drawRect( event->rect() );
 
     painter.setBrush( Qt::white );
     painter.save();
     painter.translate( event->rect().width() * percentage, 0 );
     QPen oldPen = painter.pen();
     QPen linePen = oldPen;
     linePen.setColor( Qt::white );
     painter.setPen( linePen );
     painter.drawLine( 0, 0, 0, rect().height() );
     painter.setPen( oldPen );
 
     painter.save();
     painter.translate( 0, rect().height() );
     painter.rotate( 180 );
     painter.scale( 15, 15 );
     d->drawSliderMarker( &painter );
     painter.restore();
     painter.scale( 15, 15 );
     d->drawSliderMarker( &painter );
     painter.restore();
 
 }
 
 void ColorSlider::mousePressEvent(QMouseEvent *event )
 {
     if ( event->button() == Qt::LeftButton )
     {
         d->m_dragging = true;
         const double relPos = qMin( 1.0, qMax( 0.0, event->localPos().x() / rect().width() ) );
         setValue( (maximum() - minimum() ) * relPos );
     }
 }
 
 void ColorSlider::mouseReleaseEvent(QMouseEvent *event )
 {
     if ( event->button() != Qt::LeftButton )
     {
         d->m_dragging = false;
         const double relPos = qMin( 1.0, qMax( 0.0, event->localPos().x() / rect().width() ) );
         setValue( (maximum() - minimum() ) * relPos );
     }
 }
 
 void ColorSlider::mouseMoveEvent( QMouseEvent *event )
 {
     if ( d->m_dragging )
     {
         const double relPos = qMin( 1.0, qMax( 0.0, event->localPos().x() / rect().width() ) );
         setValue( (maximum() - minimum() ) * relPos );
     }
 }
 
 QSize ColorSlider::sizeHint() const
 {
     return QSize( 300, 50 );
 }