实现工具栏中‘放大’、‘缩小’和‘自适应’三个action的操作响应，实现场景的拖动操作（鼠标中键）

include/designerView.h

@@ -11,6 +11,11 @@ public:
     explicit DesignerView(QWidget *parent = 0);
     virtual ~DesignerView();
 
+    //视图操作-外部调用
+    void zoomIn();
+    void zoomOut();
+    void zoomFit();
+
 protected:
     virtual void contextMenuEvent(QContextMenuEvent*) override;
     virtual void mousePressEvent(QMouseEvent*) override;
@@ -20,14 +25,16 @@ protected:
 
 private:
     void initialize();
-    //缩放相关
+    //视图操作相关
     void zoom(const QPointF&, double);
     bool zoomLimit(double&);
     double getScaleFactor();
+    void translate(const QPointF&);
 
 private:
-    bool   m_bMousePress;
+    bool    m_bMousePress;
-    double m_dZoomVaule;
+    double  m_dScale;
+    QPointF m_ptLatstMouse_view; //鼠标最后按下在view中的位置
 };
 
 #endif

include/drawingPanel.h

@@ -22,6 +22,10 @@ public:
     QGraphicsScene* getQGraphicsScene();
     DesignerScene* getDesignerScene();
 
+    void grahpicsViewZoomIn();
+    void grahpicsViewZoomOut();
+    void grahpicsViewZoomFit();
+
 public slots:
     void onSignal_addGraphicsItem(GraphicsItemType&);
 

include/global.h

@@ -3,8 +3,8 @@
 
 #include <QGraphicsItem>
 
-const double g_dGriaphicsScene_Width = 5000;
+const double g_dGriaphicsScene_Width = 1200;
-const double g_dGriaphicsScene_Height = 5000;
+const double g_dGriaphicsScene_Height = 900;
 
 enum GraphicsItemType
 {

include/mainwindow.h

@@ -29,12 +29,16 @@ public:
 
 protected:
 	virtual void closeEvent(QCloseEvent* event) override;
+    virtual void changeEvent(QEvent* event) override;
 
 private:
     void initializeDockUi();
     void initializeAction();
 
 private slots:
+    void onAction_zoomIn();
+    void onAction_zoomOut();
+    void onAction_zoomFit();
     void onSignal_addItem(QGraphicsItem*);
     void onSignal_deleteItem();
 

source/designerView.cpp

@@ -8,7 +8,7 @@ DesignerView::DesignerView(QWidget *parent)
     : QGraphicsView(parent)
 {
     m_bMousePress = false;
-    m_dZoomVaule = 1.0;
+    m_dScale = 1.0;
     initialize();
 }
 DesignerView::~DesignerView()
@@ -19,8 +19,8 @@ DesignerView::~DesignerView()
 void DesignerView::initialize()
 {
     //去掉QGraphicsView自带滚动条
-    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    //setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
-    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    //setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     //设置背景
     setStyleSheet("background-image: url(:/images/checkerboard.png);\
                   padding: 0px; \
@@ -33,18 +33,77 @@ void DesignerView::initialize()
     centerOn(0, 0);
 }
 
+void DesignerView::contextMenuEvent(QContextMenuEvent* event)
+{
+    Q_UNUSED(event);
+    m_bMousePress = false;
+}
+
+void DesignerView::mousePressEvent(QMouseEvent* event)
+{
+    QGraphicsItem* item = scene()->itemAt(mapToScene(event->pos()), transform());
+    if (event->button() == Qt::MiddleButton /*&& !item*/) //在空白处按住中键进行拖动
+    {
+        m_bMousePress = true;
+        setCursor(Qt::ClosedHandCursor);
+        m_ptLatstMouse_view = event->pos();
+    }
+    else
+        QGraphicsView::mousePressEvent(event);
+}
+
+void DesignerView::mouseMoveEvent(QMouseEvent* event)
+{
+    if(m_bMousePress)
+    {
+        QPointF mouseMoveLength = event->pos() - m_ptLatstMouse_view.toPoint();
+        translate(mouseMoveLength);
+        m_ptLatstMouse_view = event->pos();
+    }
+    else
+        QGraphicsView::mouseMoveEvent(event);
+}
+
+void DesignerView::mouseReleaseEvent(QMouseEvent* event)
+{
+    if (event->button() == Qt::MiddleButton) //按住中键进行拖动
+    {
+        m_bMousePress = false;
+        setCursor(Qt::ArrowCursor);
+    }
+    else
+        QGraphicsView::mouseReleaseEvent(event);
+}
+
+void DesignerView::wheelEvent(QWheelEvent* event) //滚轮进行放大缩小
+{
+    QPointF mousePos = event->position();
+    double angleDeltaY = event->angleDelta().y();
+    double zoomFactor = qPow(1.0015, angleDeltaY); //可以实现更平滑的缩放
+    zoom(mousePos, zoomFactor);
+
+    //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
+    //QGraphicsView::wheelEvent(event);
+}
+
+double DesignerView::getScaleFactor()
+{
+    //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
+    return this->transform().m11();
+}
+
 bool DesignerView::zoomLimit(double& value)
 {
-    m_dZoomVaule *= value;
+    m_dScale *= value;
-    if(m_dZoomVaule >= MAX_ZoomValue)
+    if(m_dScale >= MAX_ZoomValue)
     {
-        m_dZoomVaule = MAX_ZoomValue;
+        m_dScale = MAX_ZoomValue;
-        value = m_dZoomVaule / getScaleFactor();
+        value = m_dScale / getScaleFactor();
     }
-    else if(m_dZoomVaule <= MIN_ZoomValue)
+    else if(m_dScale <= MIN_ZoomValue)
     {
-        m_dZoomVaule = MIN_ZoomValue;
+        m_dScale = MIN_ZoomValue;
-        value = m_dZoomVaule / getScaleFactor();
+        value = m_dScale / getScaleFactor();
     }
 
     if(qFabs(value - 1) < 0.01) //缩放因子近似为1
@@ -73,55 +132,49 @@ void DesignerView::zoom(const QPointF& mousePos, double zoomFactor)
     setTransformationAnchor(lastAnchor);
 }
 
-double DesignerView::getScaleFactor()
+void DesignerView::zoomIn()
 {
-    //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
+    //以view的中心点作为放大中心
-    return this->transform().m11();
+    double dWidth_View = viewport()->width();
+    double dHeight_View = viewport()->height();
+    QPoint pt(dWidth_View * 0.5, dHeight_View * 0.5);
+    zoom(pt, 1.1);
 }
 
-void DesignerView::contextMenuEvent(QContextMenuEvent* event)
+void DesignerView::zoomOut()
 {
-    Q_UNUSED(event);
+    //以view的中心点作为缩小中心
-    m_bMousePress = false;
+    double dWidth_View = viewport()->width();
+    double dHeight_View = viewport()->height();
+    QPoint pt(dWidth_View * 0.5, dHeight_View * 0.5);
+    zoom(pt, 0.9);
 }
 
-void DesignerView::mousePressEvent(QMouseEvent* event)
+void DesignerView::zoomFit()
 {
-    if (event->button() == Qt::MiddleButton) //按住中键进行拖动
+    resetTransform();
-    {
+
-        m_bMousePress = true;
+    double dWidth_View = viewport()->width();
-    }
+    double dHeight_View = viewport()->height();
-    else
+    double dWidth_Scene = scene()->sceneRect().width();
-        QGraphicsView::mousePressEvent(event);
+    double dHeight_Scene = scene()->sceneRect().height();
+
+    double dWidthScale = dWidth_View / dWidth_Scene;
+    double dHeightScale = dHeight_View / dHeight_Scene;
+    m_dScale = qMin(dWidthScale, dHeightScale);
+
+    QTransform trans = transform();
+    trans.scale(m_dScale, m_dScale);
+    setTransform(trans);
+    centerOn(0, 0);
 }
 
-void DesignerView::mouseMoveEvent(QMouseEvent* event)
+void DesignerView::translate(const QPointF& delta)
 {
-    if(m_bMousePress)
+    ViewportAnchor lastAnchor = this->transformationAnchor();
-    {
+    setTransformationAnchor(QGraphicsView::NoAnchor);
-
+    QTransform trans = transform();
-    }
+    trans.translate(delta.x(), delta.y());
-    else
+    setTransform(trans);
-        QGraphicsView::mouseMoveEvent(event);
+    setTransformationAnchor(lastAnchor);
-}
-
-void DesignerView::mouseReleaseEvent(QMouseEvent* event)
-{
-    if (event->button() == Qt::MiddleButton) //按住中键进行拖动
-    {
-        m_bMousePress = false;
-    }
-    else
-        QGraphicsView::mouseReleaseEvent(event);
-}
-
-void DesignerView::wheelEvent(QWheelEvent* event) //滚轮进行放大缩小
-{
-    QPointF mousePos = event->position();
-    double angleDeltaY = event->angleDelta().y();
-    double zoomFactor = qPow(1.0015, angleDeltaY); //可以实现更平滑的缩放
-    zoom(mousePos, zoomFactor);
-
-    //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
-    //QGraphicsView::wheelEvent(event);
 }

source/drawingPanel.cpp

@@ -36,6 +36,21 @@ DesignerScene* DrawingPanel::getDesignerScene()
     return m_pGraphicsScene;
 }
 
+void DrawingPanel::grahpicsViewZoomIn()
+{
+    m_pGraphicsView->zoomIn();
+}
+
+void DrawingPanel::grahpicsViewZoomOut()
+{
+    m_pGraphicsView->zoomOut();
+}
+
+void DrawingPanel::grahpicsViewZoomFit()
+{
+    m_pGraphicsView->zoomFit();
+}
+
 void DrawingPanel::onSignal_addGraphicsItem(GraphicsItemType& itemType)
 {
     if(SelectorManager::getInstance())

source/mainwindow.cpp

@@ -50,6 +50,12 @@ void CMainWindow::closeEvent(QCloseEvent* event)
 	QMainWindow::closeEvent(event);
 }
 
+void CMainWindow::changeEvent(QEvent* event)
+{
+    if (event->type() == QEvent::WindowStateChange)
+        m_pDrawingPanel->grahpicsViewZoomFit();
+}
+
 void CMainWindow::initializeDockUi()
 {
     CDockManager::setConfigFlag(CDockManager::OpaqueSplitterResize, true);
@@ -106,6 +112,24 @@ void CMainWindow::initializeAction()
     ui->actionDelete->setShortcut(QKeySequence::Delete);
 
     connect(ui->actionDelete, SIGNAL(triggered()), this, SLOT(onSignal_deleteItem()));
+    connect(ui->actionZoomIn, SIGNAL(triggered()), this, SLOT(onAction_zoomIn()));
+    connect(ui->actionZoomOut, SIGNAL(triggered()), this, SLOT(onAction_zoomOut()));
+    connect(ui->actionZoomFit, SIGNAL(triggered()), this, SLOT(onAction_zoomFit()));
+}
+
+void CMainWindow::onAction_zoomIn()
+{
+    m_pDrawingPanel->grahpicsViewZoomIn();
+}
+
+void CMainWindow::onAction_zoomOut()
+{
+    m_pDrawingPanel->grahpicsViewZoomOut();
+}
+
+void CMainWindow::onAction_zoomFit()
+{
+    m_pDrawingPanel->grahpicsViewZoomFit();
 }
 
 void CMainWindow::onSignal_addItem(QGraphicsItem* item)

ui/mainwindow.ui

@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>1284</width>
+    <width>1612</width>
-    <height>756</height>
+    <height>1016</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -19,7 +19,7 @@
     <rect>
      <x>0</x>
      <y>0</y>
-     <width>1284</width>
+     <width>1612</width>
      <height>33</height>
     </rect>
    </property>