128 lines
3.4 KiB
C++
128 lines
3.4 KiB
C++
#include "designerView.h"
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#include <QMouseEvent>
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#define MAX_ZoomValue 50.0
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#define MIN_ZoomValue 0.02
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DesignerView::DesignerView(QWidget *parent)
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: QGraphicsView(parent)
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{
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m_bMousePress = false;
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m_dZoomVaule = 1.0;
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initialize();
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}
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DesignerView::~DesignerView()
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{
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}
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void DesignerView::initialize()
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{
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//去掉QGraphicsView自带滚动条
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setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
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setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
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//设置背景
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setStyleSheet("background-image: url(:/images/checkerboard.png);\
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padding: 0px; \
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border: 0px;");
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//打开反锯齿
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setRenderHint(QPainter::Antialiasing);
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setMouseTracking(true);
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//setDragMode(QGraphicsView::RubberBandDrag); //将控制交给selector
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centerOn(0, 0);
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}
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bool DesignerView::zoomLimit(double& value)
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{
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m_dZoomVaule *= value;
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if(m_dZoomVaule >= MAX_ZoomValue)
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{
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m_dZoomVaule = MAX_ZoomValue;
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value = m_dZoomVaule / getScaleFactor();
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}
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else if(m_dZoomVaule <= MIN_ZoomValue)
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{
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m_dZoomVaule = MIN_ZoomValue;
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value = m_dZoomVaule / getScaleFactor();
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}
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if(qFabs(value - 1) < 0.01) //缩放因子近似为1
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return true;
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return false;
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}
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void DesignerView::zoom(const QPointF& mousePos, double zoomFactor)
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{
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if(zoomLimit(zoomFactor))
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return;
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/*
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* QGraphicsView的默认transformationAnchor(变换锚点)是AnchorViewCenter，也就是中心，此处希望以鼠标指向为变换中心,
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* AnchorUnderMouse可以实现，但经尝试没有自己进行移动(translate)效果好，所以先设置成NoAnchor,变换后再设置回来
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*/
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ViewportAnchor lastAnchor = this->transformationAnchor();
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setTransformationAnchor(QGraphicsView::NoAnchor);
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QPointF targetScenePos = mapToScene(mousePos.toPoint());
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QTransform trans = transform();
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trans.translate(targetScenePos.x(), targetScenePos.y());
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trans.scale(zoomFactor, zoomFactor);
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trans.translate(-targetScenePos.x(), -targetScenePos.y());
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setTransform(trans);
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setTransformationAnchor(lastAnchor);
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}
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double DesignerView::getScaleFactor()
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{
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//QTransform为一个3*3的矩阵，m11和m22元素分别为水平和垂直的缩放值
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return this->transform().m11();
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}
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void DesignerView::contextMenuEvent(QContextMenuEvent* event)
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{
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Q_UNUSED(event);
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m_bMousePress = false;
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}
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void DesignerView::mousePressEvent(QMouseEvent* event)
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{
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if (event->button() == Qt::MiddleButton) //按住中键进行拖动
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{
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m_bMousePress = true;
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}
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else
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QGraphicsView::mousePressEvent(event);
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}
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void DesignerView::mouseMoveEvent(QMouseEvent* event)
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{
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if(m_bMousePress)
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{
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}
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else
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QGraphicsView::mouseMoveEvent(event);
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}
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void DesignerView::mouseReleaseEvent(QMouseEvent* event)
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{
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if (event->button() == Qt::MiddleButton) //按住中键进行拖动
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{
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m_bMousePress = false;
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}
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else
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QGraphicsView::mouseReleaseEvent(event);
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}
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void DesignerView::wheelEvent(QWheelEvent* event) //滚轮进行放大缩小
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{
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QPointF mousePos = event->position();
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double angleDeltaY = event->angleDelta().y();
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double zoomFactor = qPow(1.0015, angleDeltaY); //可以实现更平滑的缩放
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zoom(mousePos, zoomFactor);
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//注意不要调用基类的滚轮函数，否则滚轮事件会映射到滚动条操作
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//QGraphicsView::wheelEvent(event);
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}
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