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			86 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
		
		
			
		
	
	
			86 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
|  | ///////////////////////////////////////////////////////////////////////////////////
 | ||
|  | // Copyright (C) 2021 Jon Beniston, M7RCE                                        //
 | ||
|  | //                                                                               //
 | ||
|  | // 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 as version 3 of the License, or                  //
 | ||
|  | // (at your option) any later version.                                           //
 | ||
|  | //                                                                               //
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|  | // 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                  //
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|  | // GNU General Public License V3 for more details.                               //
 | ||
|  | //                                                                               //
 | ||
|  | // You should have received a copy of the GNU General Public License             //
 | ||
|  | // along with this program. If not, see <http://www.gnu.org/licenses/>.          //
 | ||
|  | ///////////////////////////////////////////////////////////////////////////////////
 | ||
|  | 
 | ||
|  | #include <QMouseEvent>
 | ||
|  | #include <QApplication>
 | ||
|  | #include <QScrollBar>
 | ||
|  | #include <qmath.h>
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|  | 
 | ||
|  | #include "graphicsviewzoom.h"
 | ||
|  | 
 | ||
|  | GraphicsViewZoom::GraphicsViewZoom(QGraphicsView* view) : | ||
|  |     QObject(view), | ||
|  |     m_view(view), | ||
|  |     m_modifiers(Qt::NoModifier), | ||
|  |     m_zoomFactorBase(1.0015) | ||
|  | { | ||
|  |     m_view->viewport()->installEventFilter(this); | ||
|  |     m_view->setMouseTracking(true); | ||
|  | } | ||
|  | 
 | ||
|  | void GraphicsViewZoom::gentleZoom(double factor) | ||
|  | { | ||
|  |     m_view->scale(factor, factor); | ||
|  |     m_view->centerOn(m_targetScenePos); | ||
|  |     QPointF deltaViewportPos = m_targetViewportPos - QPointF(m_view->viewport()->width() / 2.0, | ||
|  |                                                              m_view->viewport()->height() / 2.0); | ||
|  |     QPointF viewportCenter = m_view->mapFromScene(m_targetScenePos) - deltaViewportPos; | ||
|  |     m_view->centerOn(m_view->mapToScene(viewportCenter.toPoint())); | ||
|  |     emit zoomed(); | ||
|  | } | ||
|  | 
 | ||
|  | void GraphicsViewZoom::setModifiers(Qt::KeyboardModifiers modifiers) | ||
|  | { | ||
|  |     m_modifiers = modifiers; | ||
|  | } | ||
|  | 
 | ||
|  | void GraphicsViewZoom::setZoomFactorBase(double value) | ||
|  | { | ||
|  |     m_zoomFactorBase = value; | ||
|  | } | ||
|  | 
 | ||
|  | bool GraphicsViewZoom::eventFilter(QObject *object, QEvent *event) | ||
|  | { | ||
|  |     if (event->type() == QEvent::MouseMove) | ||
|  |     { | ||
|  |         QMouseEvent* mouseEvent = static_cast<QMouseEvent*>(event); | ||
|  |         QPointF delta = m_targetViewportPos - mouseEvent->pos(); | ||
|  |         if (qAbs(delta.x()) > 5 || qAbs(delta.y()) > 5) | ||
|  |         { | ||
|  |             m_targetViewportPos = mouseEvent->pos(); | ||
|  |             m_targetScenePos = m_view->mapToScene(mouseEvent->pos()); | ||
|  |         } | ||
|  |     } | ||
|  |     else if (event->type() == QEvent::Wheel) | ||
|  |     { | ||
|  |         QWheelEvent* wheelEvent = static_cast<QWheelEvent*>(event); | ||
|  |         if (QApplication::keyboardModifiers() == m_modifiers) | ||
|  |         { | ||
|  |             if (wheelEvent->orientation() == Qt::Vertical) | ||
|  |             { | ||
|  |                 double angle = wheelEvent->angleDelta().y(); | ||
|  |                 double factor = qPow(m_zoomFactorBase, angle); | ||
|  |                 gentleZoom(factor); | ||
|  |                 return true; | ||
|  |             } | ||
|  |         } | ||
|  |     } | ||
|  | 
 | ||
|  |     Q_UNUSED(object) | ||
|  |     return false; | ||
|  | } |