QT调用GDI绘图

#pragma once

#include <QtWidgets/QWidget>
#include "ui_TestGdi.h"

class TestGdi : public QWidget
{
    Q_OBJECT

public:
    TestGdi(QWidget *parent = Q_NULLPTR);

    QPaintEngine * paintEngine() const;

    void paintEvent(QPaintEvent *event);

private:
    Ui::TestGdiClass ui;
};
 

 

#include "TestGdi.h"
#include <QtWinExtras/QtWin>
TestGdi::TestGdi(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);
    setAttribute(Qt::WA_PaintOnScreen, true);

    
    int a = 1;
    

}

void TestGdi::paintEvent(QPaintEvent *event)
{
    HDC hdc = GetDC((HWND)this->winId());

    HPE