From 0ff1e80132fd5c2c6cb217948b73bf5351669a6a Mon Sep 17 00:00:00 2001
From: Gary Wang <wzc782970009@gmail.com>
Date: Thu, 3 Oct 2019 11:00:28 +0800
Subject: [PATCH] add useless animation

---
 mainwindow.cpp | 28 ++++++++++++++++++++++++++++
 mainwindow.h   |  8 ++++++++
 2 files changed, 36 insertions(+)

diff --git a/mainwindow.cpp b/mainwindow.cpp
index 4a030a5..281a4c0 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -11,6 +11,7 @@
 #include <QApplication>
 #include <QStyle>
 #include <QScreen>
+#include <QGraphicsOpacityEffect>
 
 #ifdef _WIN32
 #include <windows.h>
@@ -73,6 +74,13 @@ MainWindow::MainWindow(QWidget *parent) :
         m_graphicsView->checkAndDoFitInView();
     });
 
+    m_opacityEffect = new QGraphicsOpacityEffect(m_bottomButtonGroup);
+    m_bottomButtonGroup->setGraphicsEffect(m_opacityEffect);
+    m_btnGrpAnimation = new QPropertyAnimation(m_opacityEffect, "opacity");
+    m_btnGrpAnimation->setDuration(300);
+
+    m_opacityEffect->setOpacity(0);
+
     centerWindow();
 }
 
@@ -115,6 +123,26 @@ void MainWindow::showEvent(QShowEvent *event)
     return QMainWindow::showEvent(event);
 }
 
+void MainWindow::enterEvent(QEvent *event)
+{
+    m_btnGrpAnimation->stop();
+    m_btnGrpAnimation->setStartValue(m_opacityEffect->opacity());
+    m_btnGrpAnimation->setEndValue(1);
+    m_btnGrpAnimation->start();
+
+    return QMainWindow::enterEvent(event);
+}
+
+void MainWindow::leaveEvent(QEvent *event)
+{
+    m_btnGrpAnimation->stop();
+    m_btnGrpAnimation->setStartValue(m_opacityEffect->opacity());
+    m_btnGrpAnimation->setEndValue(0);
+    m_btnGrpAnimation->start();
+
+    return QMainWindow::leaveEvent(event);
+}
+
 void MainWindow::mousePressEvent(QMouseEvent *event)
 {
     if (event->buttons() & Qt::LeftButton) {
diff --git a/mainwindow.h b/mainwindow.h
index a90fd63..7d3c8e9 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -6,6 +6,10 @@
 #include <QPropertyAnimation>
 #include <QPushButton>
 
+QT_BEGIN_NAMESPACE
+class QGraphicsOpacityEffect;
+QT_END_NAMESPACE
+
 class GraphicsView;
 class BottomButtonGroup;
 class MainWindow : public QMainWindow
@@ -21,6 +25,8 @@ public:
 
 protected slots:
     void showEvent(QShowEvent *event) override;
+    void enterEvent(QEvent *event) override;
+    void leaveEvent(QEvent *event) override;
     void mousePressEvent(QMouseEvent *event) override;
     void mouseMoveEvent(QMouseEvent *event) override;
     void mouseReleaseEvent(QMouseEvent *event) override;
@@ -35,6 +41,8 @@ protected slots:
 
 private:
     QPoint m_oldMousePos;
+    QGraphicsOpacityEffect *m_opacityEffect;
+    QPropertyAnimation *m_btnGrpAnimation;
     QPropertyAnimation *m_fadeOutAnimation;
     QPropertyAnimation *m_floatUpAnimation;
     QParallelAnimationGroup *m_exitAnimationGroup;