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sdrangel/sdrgui/gui/graphicsviewzoom.cpp
2022-12-20 11:31:01 +00:00

103 lines
3.9 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. //
// //
// 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 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 <QGestureEvent>
#include <QPinchGesture>
#include <qmath.h>
#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);
m_view->viewport()->grabGesture(Qt::PinchGesture);
}
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->angleDelta().y() != 0)
{
double angle = wheelEvent->angleDelta().y();
double factor = qPow(m_zoomFactorBase, angle);
gentleZoom(factor);
return true;
}
}
}
else if (event->type() == QEvent::Gesture)
{
QGestureEvent *gestureEvent = static_cast<QGestureEvent *>(event);
if (QPinchGesture *pinchGesture = static_cast<QPinchGesture *>(gestureEvent->gesture(Qt::PinchGesture)))
{
if (pinchGesture->changeFlags() & QPinchGesture::ScaleFactorChanged)
{
m_view->scale(pinchGesture->scaleFactor(), pinchGesture->scaleFactor());
emit zoomed();
}
return true;
}
}
Q_UNUSED(object)
return false;
}