From 9d1d8aafc19fc68c4a33b8bbfa09d76e3b12d599 Mon Sep 17 00:00:00 2001
From: liuminghang <liuminghang@uniontech.com>
Date: Thu, 24 Jun 2021 11:25:02 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=A2=9E=E5=8A=A0=E4=BA=8C=E6=8C=87?=
 =?UTF-8?q?=E8=A7=A6=E5=B1=8F=E5=8A=9F=E8=83=BD?=
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Description: 增加二指触屏功能

Log: 增加二指触屏功能
Change-Id: Ib96e7082ebf651708992357bcbe064048b830ce2
---
 src/view/imageview.cpp | 43 ++++++++++++++++++++++++++++++++++++++++++
 src/view/imageview.h   | 10 +++++++---
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/view/imageview.cpp b/src/view/imageview.cpp
index 33b8b3f..b062d55 100644
--- a/src/view/imageview.cpp
+++ b/src/view/imageview.cpp
@@ -10,6 +10,8 @@
 #include <QThreadPool>
 #include <qmath.h>
 #include <QObject>
+#include <QGestureEvent>
+#include <QPinchGesture>
 
 const qreal MAX_SCALE_FACTOR = 20.0;
 const qreal MIN_SCALE_FACTOR = 0.029;
@@ -23,6 +25,8 @@ ImageView::ImageView(QWidget *parent):
     setScene(scene);
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    this->grabGesture(Qt::PinchGesture);
+    setAttribute(Qt::WA_AcceptTouchEvents);
 }
 
 void ImageView::openImage(const QString &path)
@@ -192,6 +196,23 @@ void ImageView::mouseMoveEvent(QMouseEvent *event)
     return QGraphicsView::mouseMoveEvent(event);
 }
 
+bool ImageView::event(QEvent *event)
+{
+    if (event->type() == QEvent::Gesture) {
+        return gestureEvent(static_cast<QGestureEvent *>(event));
+    }
+    return QGraphicsView::event(event);
+}
+
+bool ImageView::gestureEvent(QGestureEvent *event)
+{
+//    if (QGesture *swipe = event->gesture(Qt::SwipeGesture)) //滑动逻辑
+//        swipeTriggered(static_cast<QSwipeGesture *>(swipe));
+    if (QGesture *pinch = event->gesture(Qt::PinchGesture))//双指捏合
+        pinchTriggered(static_cast<QPinchGesture *>(pinch));
+    return true;
+}
+
 
 const QImage ImageView::image()
 {
@@ -215,6 +236,27 @@ void ImageView::wheelEvent(QWheelEvent *event)
 
     event->accept();
 }
+
+void ImageView::handleGestureEvent(QGestureEvent *gesture)
+{
+    qDebug() << "------" << __FUNCTION__ << "";
+    if (QGesture *pinch = gesture->gesture(Qt::PinchGesture))
+        pinchTriggered(static_cast<QPinchGesture *>(pinch));
+}
+
+void ImageView::pinchTriggered(QPinchGesture *gesture)
+{
+    qDebug() << "------" << __FUNCTION__ << "";
+    QPinchGesture::ChangeFlags changeFlags = gesture->changeFlags();
+    //缩放手势
+    if (changeFlags & QPinchGesture::ScaleFactorChanged) {
+        QPoint pos = mapFromGlobal(gesture->centerPoint().toPoint());
+        if (abs(gesture->scaleFactor() - 1) > 0.006) {
+            qDebug() << "scaleFactor" << gesture->scaleFactor();
+            scaleAtPoint(pos, gesture->scaleFactor());
+        }
+    }
+}
 void ImageView::scaleAtPoint(QPoint pos, qreal factor)
 {
     // Remember zoom anchor point.
@@ -264,3 +306,4 @@ void ImageView::setScaleValue(qreal v)
 
 
 }
+
diff --git a/src/view/imageview.h b/src/view/imageview.h
index 74c3fc7..252e01c 100644
--- a/src/view/imageview.h
+++ b/src/view/imageview.h
@@ -7,8 +7,8 @@
 #include <QGraphicsView>
 
 class QGraphicsPixmapItem;
-
-
+class QGestureEvent;
+class QPinchGesture;
 
 class ImageView : public QGraphicsView
 {
@@ -27,6 +27,8 @@ public:
     void autoFit();
     //鼠标移动事件
     void mouseMoveEvent(QMouseEvent *event) override;
+    bool event(QEvent *event)override;
+    bool gestureEvent(QGestureEvent *event);
 
     //返回当前图片img
     const QImage image();
@@ -50,7 +52,9 @@ public slots:
     //鼠标滚轮事件
     void wheelEvent(QWheelEvent *event) override;
 protected:
-
+    //二指捏合功能的触屏事件
+    void handleGestureEvent(QGestureEvent *gesture);
+    void pinchTriggered(QPinchGesture *gesture);
 
 private:
     QString m_currentPath;//当前图片路径