抽离场景打开逻辑、添加编辑界面的左右拖动功能

scene/myview.cpp

@@ -1,5 +1,7 @@
 #include "myview.h"
 #include <QWheelEvent>
+#include <QMouseEvent>
+#include <QScrollBar>
 #include "picscene.h"
 #include <QDebug>
 MyView::MyView(QWidget *parent) :
@@ -44,6 +46,63 @@ void MyView::ZoomIn(void)
 ////   rotate(90);  //视图旋转顺时针90度
 //}
 
+void MyView::mousePressEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::LeftButton) {
+        m_isPressing = true;
+        const QPointF scenePos = mapToScene(event->pos());
+        const bool hasSelectedItem = scene() && !scene()->selectedItems().isEmpty();
+        m_pressOnItem = hasSelectedItem || (scene() && scene()->itemAt(scenePos, transform()) != nullptr);
+        m_lastPanPoint = event->pos();
+    }
+
+    QGraphicsView::mousePressEvent(event);
+}
+
+void MyView::mouseMoveEvent(QMouseEvent *event)
+{
+    if (m_isPressing && !m_pressOnItem && !m_isPanning) {
+        const bool noSelectedItems = scene() && scene()->selectedItems().isEmpty();
+        if (noSelectedItems) {
+            QPoint delta = event->pos() - m_lastPanPoint;
+            if (std::abs(delta.x()) >= MyView::PanStartDistance && std::abs(delta.x()) > std::abs(delta.y())) {
+                m_isPanning = true;
+                setCursor(Qt::ClosedHandCursor);
+            }
+        }
+    }
+
+    if (m_isPanning) {
+        int deltaX = event->pos().x() - m_lastPanPoint.x();
+        if (deltaX != 0) {
+            horizontalScrollBar()->setValue(horizontalScrollBar()->value() - deltaX);
+            m_lastPanPoint = event->pos();
+        }
+        event->accept();
+        return;
+    }
+
+    QGraphicsView::mouseMoveEvent(event);
+}
+
+void MyView::mouseReleaseEvent(QMouseEvent *event)
+{
+    if (m_isPanning && event->button() == Qt::LeftButton) {
+        m_isPanning = false;
+        m_isPressing = false;
+        setCursor(Qt::ArrowCursor);
+        event->accept();
+        return;
+    }
+
+    if (event->button() == Qt::LeftButton) {
+        m_isPressing = false;
+        m_pressOnItem = false;
+    }
+
+    QGraphicsView::mouseReleaseEvent(event);
+}
+
 void MyView::keyPressEvent(QKeyEvent *event)
 {
     //event->accept();