File indexing completed on 2025-02-16 04:03:08

 /**
  * SPDX-FileCopyrightText: 2001-2015 Klaralvdalens Datakonsult AB. All rights reserved.
  *
  * This file is part of the KD Chart library.
  *
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include "zoomwidget.h"
 #include <KChartAbstractCoordinatePlane>
 #include <QWheelEvent>
 #include <QDebug>
 
 ZoomWidget::ZoomWidget( QWidget* parent ) :
     KChart::Widget( parent )
 {
     setFocusPolicy( Qt::WheelFocus );
 }
 
 
 QPointF ZoomWidget::findNewZoomCenter( const QPoint & pos )
 {
     if ( ! height() || ! width() ) return coordinatePlane()->zoomCenter();
 
     const qreal coordWidth = 1.0;
     const qreal coordHeight = 1.0;
 
 //    qDebug() << "pos = " << pos;
     const qreal resX = static_cast<qreal>( coordWidth /coordinatePlane()->zoomFactorX() )/ width();
     const qreal resY = static_cast<qreal>( coordHeight/coordinatePlane()->zoomFactorY() )/ height();
 //    qDebug() << "resX = " << resX << "  resY = " << resY;
     const qreal dX = (pos.x() - 0.5*width() ) * resX;
     const qreal dY = (pos.y() - 0.5*height()) * resY;
 //    qDebug() << "dX = " << dX << "  dY = " << dY;
     const qreal zoomCenterX = coordinatePlane()->zoomCenter().x() + dX;
     const qreal zoomCenterY = coordinatePlane()->zoomCenter().y() + dY;
     return QPointF( zoomCenterX, zoomCenterY );
 }
 
 
 void ZoomWidget::mousePressEvent( QMouseEvent * e )
 {
     const QPointF zoomCenter( findNewZoomCenter( e->pos() ) );
     if ( zoomCenter != coordinatePlane()->zoomCenter() ) {
 //        qDebug() << "zoom center = " << zoomCenter;
         coordinatePlane()->setZoomCenter( zoomCenter );
         update();
     }
 }
 
 
 void ZoomWidget::wheelEvent( QWheelEvent* e )
 {
     qreal delta = static_cast<qreal>( e->angleDelta().y() ) / 120.0 / 10.0;
     coordinatePlane()->setZoomFactorX( coordinatePlane()->zoomFactorX() + delta );
     coordinatePlane()->setZoomFactorY( coordinatePlane()->zoomFactorY() + delta );
 /* new:
     const QPointF zoomCenter( findNewZoomCenter( e->pos() ) );
     if ( zoomCenter != coordinatePlane()->zoomCenter() ) {
         qDebug() << "zoom center = " << zoomCenter;
         coordinatePlane()->setZoomCenter( zoomCenter );
     }
 */
 /* old:
     qreal zoomCenterX = static_cast<qreal>( e->pos().x() ) / static_cast<qreal>( width() );
     qreal zoomCenterY = static_cast<qreal>( e->pos().y() ) / static_cast<qreal>( height() );
     QPointF zoomCenter( zoomCenterX, zoomCenterY );
     coordinatePlane()->setZoomCenter( zoomCenter );
 */
     update();
 }
 
 void ZoomWidget::keyPressEvent( QKeyEvent* e )
 {
     int dZoom = 0;
     qreal dX = 0;
     qreal dY = 0;
     switch ( e->key() ) {
         case Qt::Key_PageDown:
             dZoom = 1;
             break;
         case Qt::Key_Down:
             dY = 0.1;
             break;
         case Qt::Key_Right:
             dX = 0.1;
             break;
         case Qt::Key_PageUp:
             dZoom = -1;
             break;
         case Qt::Key_Up:
             dY = -0.1;
             break;
         case Qt::Key_Left:
             dX = -0.1;
             break;
         default:
             e->ignore();
     }
     if ( dZoom || dX || dY ) {
         const double factor = qMax( double(1.0), coordinatePlane()->zoomFactorX() + dZoom );
         const qreal x = coordinatePlane()->zoomCenter().x() + dX;
         const qreal y = coordinatePlane()->zoomCenter().y() + dY;
         coordinatePlane()->setZoomFactorX( factor );
         coordinatePlane()->setZoomFactorY( factor );
         coordinatePlane()->setZoomCenter( QPointF(x,y) );
         update();
     }
 }