98 lines
3.9 KiB
C++
98 lines
3.9 KiB
C++
/***************************************************************************
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* Copyright (c) 2015 Pavel Strakhov <ri@idzaaus.org> *
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* Copyright (c) 2015 Eivind Kvedalen <eivind@kvedalen.name> *
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* *
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* This file is part of the FreeCAD CAx development system. *
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* *
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* This library is free software; you can redistribute it and/or *
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* modify it under the terms of the GNU Library General Public *
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* License as published by the Free Software Foundation; either *
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* version 2 of the License, or (at your option) any later version. *
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* *
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* This library is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU Library General Public License for more details. *
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* *
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* You should have received a copy of the GNU Library General Public *
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* License along with this library; see the file COPYING.LIB. If not, *
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* write to the Free Software Foundation, Inc., 59 Temple Place, *
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* Suite 330, Boston, MA 02111-1307, USA *
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* *
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***************************************************************************/
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/*
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* Based on
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*
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* http://stackoverflow.com/questions/19113532/qgraphicsview-zooming-in-and-out-under-mouse-position-using-mouse-wheel
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*
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* Re-licensed to LGPL after having contacted original author by e-mail.
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*
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*/
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#include "PreCompiled.h"
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#ifndef _PreComp_
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# include <QGraphicsView>
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# include <QMouseEvent>
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# include <QApplication>
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# include <QScrollBar>
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# include <qmath.h>
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#endif
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#include <GraphicsViewZoom.h>
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GraphicsViewZoom::GraphicsViewZoom(QGraphicsView* view)
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: QObject(view), _view(view), m_invert_zoom(false)
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{
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_view->viewport()->installEventFilter(this);
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_view->setMouseTracking(true);
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_modifiers = Qt::ControlModifier;
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_zoom_factor_base = 1.0015;
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}
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void GraphicsViewZoom::gentle_zoom(double factor) {
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_view->scale(factor, factor);
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_view->centerOn(target_scene_pos);
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QPointF delta_viewport_pos = target_viewport_pos - QPointF(_view->viewport()->width() / 2.0,
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_view->viewport()->height() / 2.0);
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QPointF viewport_center = _view->mapFromScene(target_scene_pos) - delta_viewport_pos;
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_view->centerOn(_view->mapToScene(viewport_center.toPoint()));
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}
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void GraphicsViewZoom::set_modifiers(Qt::KeyboardModifiers modifiers) {
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_modifiers = modifiers;
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}
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void GraphicsViewZoom::set_zoom_factor_base(double value) {
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_zoom_factor_base = value;
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}
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bool GraphicsViewZoom::eventFilter(QObject *object, QEvent *event) {
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if (event->type() == QEvent::MouseMove) {
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QMouseEvent* mouse_event = static_cast<QMouseEvent*>(event);
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QPointF delta = target_viewport_pos - mouse_event->pos();
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if (qAbs(delta.x()) > 5 || qAbs(delta.y()) > 5) {
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target_viewport_pos = mouse_event->pos();
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target_scene_pos = _view->mapToScene(mouse_event->pos());
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}
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} else if (event->type() == QEvent::Wheel) {
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QWheelEvent* wheel_event = static_cast<QWheelEvent*>(event);
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if (QApplication::keyboardModifiers() == _modifiers) {
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QPoint delta = wheel_event->angleDelta();
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if (qAbs(delta.y()) > qAbs(delta.x())) { // vertical
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double angle = -delta.y();
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if (m_invert_zoom)
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angle = -angle;
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double factor = qPow(_zoom_factor_base, angle);
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gentle_zoom(factor);
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return true;
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}
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}
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}
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Q_UNUSED(object);
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return false;
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}
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#include "moc_GraphicsViewZoom.cpp"
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