New mechanizm zooming QGraphicsView using mouse wheel.
--HG-- branch : develop
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dismine
parent
4e1742ded5
commit
35b3c654c6
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@ -34,100 +34,63 @@
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#include <QScrollBar>
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#include "../tools/vabstracttool.h"
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#include <QMouseEvent>
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#include <qmath.h>
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//---------------------------------------------------------------------------------------------------------------------
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/**
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* @brief VMainGraphicsView constructor.
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* @param parent parent object.
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*/
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VMainGraphicsView::VMainGraphicsView(QWidget *parent)
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:QGraphicsView(parent), _numScheduledScalings(0)
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GraphicsViewZoom::GraphicsViewZoom(QGraphicsView* view)
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: QObject(view), _view(view), _numScheduledScalings(0)
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{
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this->setResizeAnchor(QGraphicsView::AnchorUnderMouse);
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this->setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
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this->setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
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this->setInteractive(true);
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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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//---------------------------------------------------------------------------------------------------------------------
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/**
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* @brief wheelEvent handle wheel events.
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* @param event wheel event.
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*/
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//cppcheck-suppress unusedFunction
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void VMainGraphicsView::wheelEvent(QWheelEvent *event)
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void GraphicsViewZoom::gentle_zoom(double factor)
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{
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int numSteps = event->delta() / 8 / 15; // see QWheelEvent documentation
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_numScheduledScalings += numSteps;
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if (_numScheduledScalings * numSteps < 0)
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{ // if user moved the wheel in another direction, we reset
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_numScheduledScalings = numSteps; // previously scheduled scalings
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}
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QTimeLine *anim = new QTimeLine(300, this);
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anim->setUpdateInterval(20);
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if (QApplication::keyboardModifiers() == Qt::ControlModifier)
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{// If you press CTRL this code will be executed
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connect(anim, &QTimeLine::valueChanged, this, &VMainGraphicsView::scalingTime);
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}
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else
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{
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connect(anim, &QTimeLine::valueChanged, this, &VMainGraphicsView::scrollingTime);
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}
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connect(anim, &QTimeLine::finished, this, &VMainGraphicsView::animFinished);
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anim->start();
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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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emit zoomed();
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}
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//---------------------------------------------------------------------------------------------------------------------
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/**
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* @brief scalingTime call each time when need handle scaling.
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* @param x value from 0.0 to 1.0
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*/
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void VMainGraphicsView::scalingTime(qreal x)
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void GraphicsViewZoom::set_modifiers(Qt::KeyboardModifiers modifiers)
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{
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Q_UNUSED(x);
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const QPointF p0scene = mapToScene(mapFromGlobal(QCursor::pos()));
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_modifiers = modifiers;
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qreal factor = 1.0 + static_cast<qreal>(_numScheduledScalings) / 50.0;
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scale(factor, factor);
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const QPointF p1mouse = mapFromScene(p0scene);
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const QPointF move = p1mouse - this->mapFromGlobal(QCursor::pos()); // The move
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horizontalScrollBar()->setValue(static_cast<qint32>(move.x()) + horizontalScrollBar()->value());
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verticalScrollBar()->setValue(static_cast<qint32>(move.y()) + verticalScrollBar()->value());
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VAbstractTool::NewSceneRect(this->scene(), this);
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emit NewFactor(factor);
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}
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//---------------------------------------------------------------------------------------------------------------------
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/**
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* @brief scrollingTime call each time when need handle scrolling.
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* @param x value from 0.0 to 1.0
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*/
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void VMainGraphicsView::scrollingTime(qreal x)
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void GraphicsViewZoom::set_zoom_factor_base(double value)
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{
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_zoom_factor_base = value;
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}
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//---------------------------------------------------------------------------------------------------------------------
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void GraphicsViewZoom::scrollingTime(qreal x)
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{
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Q_UNUSED(x);
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qreal factor = 1.0;
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if (_numScheduledScalings < 0)
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{
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verticalScrollBar()->setValue(qRound(verticalScrollBar()->value() + factor*3.5));
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emit NewFactor(factor);
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factor = factor*2.8;
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}
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else
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{
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verticalScrollBar()->setValue(qRound(verticalScrollBar()->value() - factor*3.5));
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emit NewFactor(factor);
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factor = factor*-2.8;
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}
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_view->verticalScrollBar()->setValue(qRound(_view->verticalScrollBar()->value() + factor));
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}
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//---------------------------------------------------------------------------------------------------------------------
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/**
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* @brief animFinished
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*/
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void VMainGraphicsView::animFinished()
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void GraphicsViewZoom::animFinished()
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{
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if (_numScheduledScalings > 0)
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{
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@ -140,6 +103,69 @@ void VMainGraphicsView::animFinished()
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sender()->~QObject();
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}
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//---------------------------------------------------------------------------------------------------------------------
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bool GraphicsViewZoom::eventFilter(QObject *object, QEvent *event)
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{
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if (event->type() == QEvent::MouseMove)
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{
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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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{
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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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}
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else if (event->type() == QEvent::Wheel)
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{
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QWheelEvent* wheel_event = static_cast<QWheelEvent*>(event);
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if (QApplication::keyboardModifiers() == _modifiers)
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{
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if (wheel_event->orientation() == Qt::Vertical)
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{
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double angle = wheel_event->angleDelta().y();
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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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else
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{
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int numSteps = wheel_event->delta() / 8 / 15; // see QWheelEvent documentation
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_numScheduledScalings += numSteps;
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if (_numScheduledScalings * numSteps < 0)
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{ // if user moved the wheel in another direction, we reset
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_numScheduledScalings = numSteps; // previously scheduled scalings
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}
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QTimeLine *anim = new QTimeLine(300, this);
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anim->setUpdateInterval(20);
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connect(anim, &QTimeLine::valueChanged, this, &GraphicsViewZoom::scrollingTime);
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connect(anim, &QTimeLine::finished, this, &GraphicsViewZoom::animFinished);
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anim->start();
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return true;
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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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//---------------------------------------------------------------------------------------------------------------------
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/**
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* @brief VMainGraphicsView constructor.
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* @param parent parent object.
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*/
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VMainGraphicsView::VMainGraphicsView(QWidget *parent)
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:QGraphicsView(parent), zoom(nullptr)
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{
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zoom = new GraphicsViewZoom(this);
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this->setResizeAnchor(QGraphicsView::AnchorUnderMouse);
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this->setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
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this->setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
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this->setInteractive(true);
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}
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//---------------------------------------------------------------------------------------------------------------------
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void VMainGraphicsView::ZoomIn()
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{
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@ -29,8 +29,65 @@
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#ifndef VMAINGRAPHICSVIEW_H
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#define VMAINGRAPHICSVIEW_H
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#include <QObject>
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#include <QGraphicsView>
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/*!
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* This class adds ability to zoom QGraphicsView using mouse wheel. The point under cursor
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* remains motionless while it's possible.
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*
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* Note that it becomes not possible when the scene's
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* size is not large enough comparing to the viewport size. QGraphicsView centers the picture
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* when it's smaller than the view. And QGraphicsView's scrolls boundaries don't allow to
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* put any picture point at any viewport position.
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*
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* When the user starts scrolling, this class remembers original scene position and
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* keeps it until scrolling is completed. It's better than getting original scene position at
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* each scrolling step because that approach leads to position errors due to before-mentioned
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* positioning restrictions.
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*
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* When zommed using scroll, this class emits zoomed() signal.
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*
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* Usage:
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*
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* new Graphics_view_zoom(view);
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*
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* The object will be deleted automatically when the view is deleted.
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*
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* You can set keyboard modifiers used for zooming using set_modified(). Zooming will be
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* performed only on exact match of modifiers combination. The default modifier is Ctrl.
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*
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* You can change zoom velocity by calling set_zoom_factor_base().
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* Zoom coefficient is calculated as zoom_factor_base^angle_delta
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* (see QWheelEvent::angleDelta).
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* The default zoom factor base is 1.0015.
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*/
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class GraphicsViewZoom : public QObject
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{
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Q_OBJECT
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public:
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GraphicsViewZoom(QGraphicsView* view);
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void gentle_zoom(double factor);
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void set_modifiers(Qt::KeyboardModifiers modifiers);
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void set_zoom_factor_base(double value);
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signals:
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void zoomed();
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public slots:
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void scrollingTime(qreal x);
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void animFinished();
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private:
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QGraphicsView* _view;
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Qt::KeyboardModifiers _modifiers;
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double _zoom_factor_base;
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QPointF target_scene_pos;
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QPointF target_viewport_pos;
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bool eventFilter(QObject* object, QEvent* event);
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private:
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/** @brief _numScheduledScalings keep number scheduled scalings. */
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qint32 _numScheduledScalings;
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};
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/**
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* @brief The VMainGraphicsView class main scene view.
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*/
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@ -53,20 +110,15 @@ signals:
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*/
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void MouseRelease();
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public slots:
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void scalingTime(qreal x);
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void scrollingTime(qreal x);
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void animFinished();
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void ZoomIn();
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void ZoomOut();
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void ZoomOriginal();
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void ZoomFitBest();
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protected:
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void wheelEvent ( QWheelEvent * event );
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void mousePressEvent(QMouseEvent *mousePress);
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void mouseReleaseEvent(QMouseEvent *event);
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private:
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/** @brief _numScheduledScalings keep number scheduled scalings. */
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qint32 _numScheduledScalings;
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GraphicsViewZoom* zoom;
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};
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#endif // VMAINGRAPHICSVIEW_H
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