From f0c19d00e793573c08d3356e1e1043782103ef19 Mon Sep 17 00:00:00 2001
From: Gavin Liu <Gavinliu0811@icloud.com>
Date: Tue, 23 Feb 2021 20:53:59 +0800
Subject: [PATCH] use QLabel instead of QPainter to draw framebuffer in Hello3D
 QT demo, for fixing screen flickering

---
 Hello3D/BuildQt/mainwindow.cpp | 8 ++++++--
 Hello3D/BuildQt/mainwindow.h   | 3 +++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/Hello3D/BuildQt/mainwindow.cpp b/Hello3D/BuildQt/mainwindow.cpp
index 00b3cee..8d438b9 100644
--- a/Hello3D/BuildQt/mainwindow.cpp
+++ b/Hello3D/BuildQt/mainwindow.cpp
@@ -48,6 +48,11 @@ void MainWindow::init()
     QTimer *timer = new QTimer(this);
     connect(timer, SIGNAL(timeout()), this, SLOT(update()));
     timer->start(30);//30ms
+
+    label = new QLabel;
+    label->setParent(this);
+    label->setFixedWidth(UI_WIDTH);
+    label->setFixedHeight(UI_HEIGHT);
 }
 
 void MainWindow::paintEvent(QPaintEvent* p)
@@ -56,9 +61,8 @@ void MainWindow::paintEvent(QPaintEvent* p)
     static bool force_update = true;
     void* fb = getUiOfHello3D(NULL, NULL, force_update);
     if(fb){
-        QPainter painter(this);
         QImage img((uchar*)fb, UI_WIDTH, UI_HEIGHT, QImage::Format_RGB16);
-        painter.drawImage(0, 0, img);
+        label->setPixmap(QPixmap::fromImage(img));
         force_update = false;
     }
 }
diff --git a/Hello3D/BuildQt/mainwindow.h b/Hello3D/BuildQt/mainwindow.h
index b8b2714..2330023 100644
--- a/Hello3D/BuildQt/mainwindow.h
+++ b/Hello3D/BuildQt/mainwindow.h
@@ -2,6 +2,7 @@
 #define MAINWINDOW_H
 
 #include <QMainWindow>
+#include <QLabel>
 
 namespace Ui {
 class MainWindow;
@@ -23,6 +24,8 @@ public:
 private:
     bool            m_is_pressed;
     Ui::MainWindow *ui;
+
+    QLabel         *label;
 };
 
 #endif // MAINWINDOW_H
-- 
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