Qt隐藏标题栏，鼠标实现窗口右下角放缩窗口

#include 
#include 
#include 
class CDemo : public QDialog
{
	Q_OBJECT

public:
	CDemo(QWidget *parent = Q_NULLPTR);
protected:
	void mouseMoveEvent(QMouseEvent *event);
	void mousePressEvent(QMouseEvent *event);
	void mouseReleaseEvent(QMouseEvent* event);//鼠标释放事件

private:
	Ui::CDemoClass ui;
private:
	bool m_isLeftPressed = false; //判断是否是左键点击
	QPoint m_clickedPositon;      //获取鼠标左键按下时光标在全局(屏幕而非窗口)的位置
	int m_distance=20;

};

#include "CDemo.h"
#include 
#include 
CDemo::CDemo(QWidget *parent)
	: QDialog(parent)
{
	ui.setupUi(this);
	this->setWindowFlags(Qt::FramelessWindowHint); //隐藏菜单栏
	setMouseTracking(true);//设置鼠标追踪
}

void CDemo::mouseMoveEvent(QMouseEvent *event)
{
	Q_UNUSED(event);
	if (this->isFullScreen()) return;//全屏时不处理
	QPoint t_pos(this->geometry().width(), this->geometry().height());
	m_distance = QLineF(t_pos, event->pos()).length();
	if ( m_distance < 10){
		setCursor(Qt::SizeFDiagCursor);
	}else{
		setCursor(Qt::ArrowCursor);
	}
	if (m_isLeftPressed)//是否左击
	{
		QPoint t_pos = event->globalPos();//当前鼠标在桌面上的位置
		t_pos = t_pos - m_clickedPositon;//减去点击时的点，得到新的点(x,y)是右下角的移动距离
		QRect t_lastWidget = this->geometry();//窗口的几何位置
		t_lastWidget.setBottomRight(t_lastWidget.bottomRight() + t_pos);//改变窗口右下角的位置
        //设置最小大小
		if (t_lastWidget.size().width()<200 || t_lastWidget.size().height() < 200)
		{
			return;
		}
		this->setGeometry(t_lastWidget);//更新窗口的集合位置
		m_clickedPositon = event->globalPos();//更新位置
	}
}

void CDemo::mousePressEvent(QMouseEvent *event)
{
	Q_UNUSED(event);
	if (event->button() == Qt::LeftButton && m_distance < 10)
	{
		this->m_isLeftPressed = true;
		QPoint t_pos = event->globalPos();
		m_clickedPositon = t_pos;//记录点击时的点的坐标
	}

}

void CDemo::mouseReleaseEvent(QMouseEvent* event)
{
	Q_UNUSED(event);
	if (m_isLeftPressed)
		m_isLeftPressed = false;
	setCursor(Qt::ArrowCursor);
}

重写鼠标移动事件就可以了，如果想实现其它位置的缩放，可以自己根据鼠标的位置来实现，思路都是一样的