Qt实现窗口拉伸

我们在日常开发的时候，几乎是很大的可能不使用系统自带的边框，但是我们去掉的话就没有窗口的拉伸效果，在网上找了几个demo都有bug，而且感觉写的很复杂，所以我重写了一个，如果有什么bug希望大家留言告知我。

#ifndef WIDGET_H
#define WIDGET_H

#include 
#include 

enum ClickType
{
    CLICK_NULL,
    CLICK_TOP,
    CLICK_BOTTOM,
    CLICK_LEFT,
    CLICK_RIGHT,
    CLICK_BOTTOM_RIGHT,
    CLICK_TOP_RIGHT,
    CLICK_TOP_LETT,
    CLICK_BOTTOM_LETT,
};

namespace Ui {class Widget;}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

protected:
    void mouseMoveEvent(QMouseEvent *ev);
    void mousePressEvent(QMouseEvent *ev);
    void mouseReleaseEvent(QMouseEvent *ev);

private slots:
    void on_pushButton_clicked();

private:
    Ui::Widget *ui;
    ClickType m_clickType = CLICK_NULL;
    bool m_bCanResize = false;
    bool m_bResizeIng = false;

    QSize  m_oldSize;
    QPoint m_globalPoint;
};

#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"
//#include 

#define MOUSE_GAP 10

Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget)
{
    ui->setupUi(this);

    this->setMouseTracking(true);//开启鼠标追踪
    this->setWindowFlags(Qt::X11BypassWindowManagerHint | Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint);
    this->setMinimumSize(100,100);

    m_oldSize = this->size();
    m_globalPoint = this->pos();
}

Widget::~Widget()
{
    delete ui;
}


void Widget::mouseMoveEvent(QMouseEvent *ev)
{
    static int rightTop;
    static int leftBottom;
    static int leftTop;

    if(!m_bResizeIng)
    {
        //右下角
        if(ev->x() > this->width() - MOUSE_GAP && ev->y() > this->height() - MOUSE_GAP)
        {
            //qDebug() << "右下";
            this->setCursor(Qt::SizeFDiagCursor);
            m_clickType = CLICK_BOTTOM_RIGHT;
        }
        //右上
        else if(ev->x() > this->width() - MOUSE_GAP && ev->x() > MOUSE_GAP && ev->y() < MOUSE_GAP)
        {
            //qDebug() << "右上";
            this->setCursor(Qt::SizeBDiagCursor);
            m_clickType = CLICK_TOP_RIGHT;
        }
        //左上
        else if(ev->x() < MOUSE_GAP && ev->y() < MOUSE_GAP)
        {
            //qDebug() << "左上";
            this->setCursor(Qt::SizeFDiagCursor);
            m_clickType = CLICK_TOP_LETT;
        }
        //左下
        else if(ev->x() < MOUSE_GAP && ev->y() > this->height() - MOUSE_GAP)
        {
            //qDebug() << "左下";
            this->setCursor(Qt::SizeBDiagCursor);
            m_clickType = CLICK_BOTTOM_LETT;
        }
        //左
        else if(ev->x() < MOUSE_GAP)
        {
            //qDebug() << "左";
            this->setCursor(Qt::SizeHorCursor);
            m_clickType = CLICK_LEFT;
        }
        //右边
        else if(ev->x() > this->width() - MOUSE_GAP && ev->y() < this->height() - MOUSE_GAP)
        {
            //qDebug() << "右";
            this->setCursor(Qt::SizeHorCursor);
            m_clickType = CLICK_RIGHT;
        }
        //上边
        else if(ev->x() > MOUSE_GAP && ev->y() < MOUSE_GAP)
        {
            //qDebug() << "上";
            this->setCursor(Qt::SizeVerCursor);
            m_clickType = CLICK_TOP;
        }
        //下边
        else if(ev->y() > this->height() - MOUSE_GAP)
        {
            //qDebug() << "下";
            this->setCursor(Qt::SizeVerCursor);
            m_clickType = CLICK_BOTTOM;
        }
        else
        {
            //qDebug() << "其他";
            this->setCursor(Qt::ArrowCursor);
            m_clickType = CLICK_NULL;
        }

    }
    if(m_bCanResize && m_clickType != CLICK_NULL)
    {
        //qDebug() << "可以改变尺寸";
        if(m_clickType == CLICK_RIGHT)
        {
            if(m_globalPoint.x() < ev->globalPos().x())
            {

                m_bResizeIng = true;
                //qDebug() << "向右拉大";
                this->resize(m_oldSize.width() + (ev->globalX() - m_globalPoint.x()),this->height());
            }
            else if(ev->globalPos().x() < m_globalPoint.x())
            {
                m_bResizeIng = true;
                //qDebug() << "向右拉小";
                this->resize(m_oldSize.width() - (m_globalPoint.x() - ev->globalX()),this->height());
            }
        }
        else if(m_clickType == CLICK_BOTTOM)
        {
            if(ev->globalY() > m_globalPoint.y())
            {
                //qDebug() << "向下拉大";
                m_bResizeIng = true;
                this->resize(this->width(),this->height() + ev->globalY() - m_globalPoint.y());
            }
            else if(ev->globalY() < m_globalPoint.y())
            {
                //qDebug() << "向下拉小";
                m_bResizeIng = true;
                this->resize(this->width(),this->height() - (m_globalPoint.y() - ev->globalY()));
            }
        }
        else if(m_clickType == CLICK_LEFT)
        {
            if(m_globalPoint.x() > ev->globalX() && this->x() > 0)
            {
                m_bResizeIng = true;
                //qDebug() << "向左拉大";
                this->resize(m_oldSize.width() + m_globalPoint.x() - ev->globalX(),this->height());
                this->move(this->x() - (m_globalPoint.x() - ev->globalPos().x()),this->y());
            }
            else if(m_globalPoint.x() < ev->globalX())
            {
                if(this->width() != this->minimumWidth())
                {
                    m_bResizeIng = true;
                    //qDebug() << "向左拉小";
                    this->resize(m_oldSize.width() + m_globalPoint.x() - ev->globalX(),this->height());
                    this->move(rightTop - this->width(),this->y());
                }
            }
        }
        else if(m_clickType == CLICK_TOP)
        {
            if(m_globalPoint.y() > ev->globalY() && ev->globalY() > 0)
            {
                m_bResizeIng = true;
                //qDebug() << "向上拉大";

                this->resize(this->width(),this->height() + (m_globalPoint.y() - ev->globalY()));
                this->move(this->x(),this->y() - (m_globalPoint.y() - ev->globalY()));
            }
            else if(m_globalPoint.y() < ev->globalY())
            {
                m_bResizeIng = true;
                //qDebug() << "向上拉小";
                this->resize(this->width(),this->height() - (ev->globalY() - m_globalPoint.y()));
                this->move(this->x(),leftBottom - this->height());
            }
        }
        else if(m_clickType == CLICK_BOTTOM_RIGHT)
        {
            if(ev->globalX() > m_globalPoint.x() || ev->globalY() > m_globalPoint.y())
            {
                m_bResizeIng = true;
                this->resize(m_oldSize.width() + (ev->globalX() - m_globalPoint.x()),this->height());
                this->resize(this->width(),this->height() + ev->globalY() - m_globalPoint.y());
                //qDebug() << "右下拉大";
            }
            else if(ev->globalX() < m_globalPoint.x() || ev->globalY() < m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "右下拉小";
                this->resize(m_oldSize.width() - (m_globalPoint.x() - ev->globalX()),this->height());
                this->resize(this->width(),this->height() - (m_globalPoint.y() - ev->globalY()));
            }
        }
        else if(m_clickType == CLICK_TOP_RIGHT)
        {
            if(ev->globalX() > m_globalPoint.x() || ev->globalY() < m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "右上拉大";
                this->resize(this->width(),this->height() + (m_globalPoint.y() - ev->globalY()));
                this->resize(m_oldSize.width() + (ev->globalX() - m_globalPoint.x()),this->height());

                this->move(leftTop,this->y() - (m_globalPoint.y() - ev->globalY()));
            }
            else if(ev->globalX() < m_globalPoint.x() || ev->globalY() > m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "右上拉小";

                this->resize(this->width(),this->height() - (ev->globalY() - m_globalPoint.y()));
                this->resize(m_oldSize.width() - (m_globalPoint.x() - ev->globalX()),this->height());
                this->move(leftTop,leftBottom - this->height());
            }
        }
        else if(m_clickType == CLICK_TOP_LETT)
        {
            if(ev->globalX() < m_globalPoint.x() || ev->globalY() < m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "左上拉大";
                this->resize(m_oldSize.width() + m_globalPoint.x() - ev->globalX(),this->height());
                this->move(this->x() - (m_globalPoint.x() - ev->globalPos().x()),this->y());
                this->resize(this->width(),this->height() + (m_globalPoint.y() - ev->globalY()));
                this->move(this->x(),this->y() - (m_globalPoint.y() - ev->globalY()));
            }
            else if(ev->globalX() > m_globalPoint.x() || ev->globalY() > m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "左上拉小";
                this->resize(m_oldSize.width() + m_globalPoint.x() - ev->globalX(),this->height());
                this->move(rightTop - this->width(),this->y());
                this->resize(this->width(),this->height() - (ev->globalY() - m_globalPoint.y()));
                this->move(this->x(),leftBottom - this->height());
            }
        }
        else if(m_clickType == CLICK_BOTTOM_LETT)
        {
            if(ev->globalX() < m_globalPoint.x() || ev->globalY() > m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "左下拉大";

                this->resize(this->width(),this->height() + ev->globalY() - m_globalPoint.y());
                this->resize(m_oldSize.width() + m_globalPoint.x() - ev->globalX(),this->height());
                this->move(this->x() - (m_globalPoint.x() - ev->globalPos().x()),this->y());
            }
            else if(ev->globalX() > m_globalPoint.x() || ev->globalY() < m_globalPoint.y())
            {
                m_bResizeIng = true;
                //qDebug() << "左下拉小";

                this->resize(this->width(),this->height() - (m_globalPoint.y() - ev->globalY()));
                this->resize(m_oldSize.width() + m_globalPoint.x() - ev->globalX(),this->height());
                this->move(rightTop - this->width(),this->y());
            }
        }
    }

    leftTop = this->x();
    leftBottom = this->y() + this->height();
    rightTop = this->x() + this->width();
    m_oldSize = this->size();
    m_globalPoint = ev->globalPos();
}

void Widget::mousePressEvent(QMouseEvent *ev)
{
    if(ev->buttons() == Qt::LeftButton && m_clickType != CLICK_NULL)
    {
        m_bCanResize = true;
    }
}

void Widget::mouseReleaseEvent(QMouseEvent *ev)
{
    this->setCursor(Qt::ArrowCursor);
    m_clickType = CLICK_NULL;
    m_bCanResize = false;
    m_bResizeIng = false;
}

void Widget::on_pushButton_clicked()
{
    QApplication::exit();
}

PS:

       1、窗口最好限定最大最小尺寸。

       2、向左拉伸的时候，窗口最右边会有抖动，但是我发现市面上支持拉伸的软件向左拉伸时都   会有这个问题，而且我打印了坐标发现点位并没有变化，所以这应该不是程序的问题。