capturescreen.h

#ifndef CAPTURESCREEN_H
#define CAPTURESCREEN_H

#include <QWidget>
#include <QPainter>

enum CaptureState{
    InitCapture = 0,
    BeginCaptureImage,
    FinishCaptureImage,
    BeginMoveCaptureArea,
    FinishMoveCaptureArea,
    BeginMoveStretchRect,
    FinishMoveStretchRect
}; //进行截屏的状态;

enum StretchRectState{
    NotSelect = 0,
    TopLeftRect,
    TopRightRect,
    BottomLeftRect,
    BottomRightRect,
    LeftCenterRect,
    TopCenterRect,
    RightCenterRect,
    BottomCenterRect
};// 当前鼠标所在顶点状态;

class CaptureScreen : public QWidget
{
    Q_OBJECT
public:
    explicit CaptureScreen(QWidget *parent = nullptr);
    ~CaptureScreen();

signals:
    // 通知截图完毕，并将截取图片传递给调用类;
    void signalCompleteCature(QPixmap catureImage);

private:
    void initWindow();
    void initStretchRect();
    void loadBackgroundPixmap();
    QRect getRect(const QPoint &beginPoint, const QPoint &endPoint);
    QRect getMoveRect();
    QRect getStretchRect();
    bool isPressPointInSelectRect(QPoint mousePressPoint);
    QRect getSelectRect();
    QPoint getMovePoint();
    StretchRectState getStrethRectState(QPoint point);
    void setStretchCursorStyle(StretchRectState stretchRectState);

    void drawCaptureImage();
    void drawStretchRect();

    void mousePressEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent* event);
    void mouseReleaseEvent(QMouseEvent *event);
    void keyPressEvent(QKeyEvent *event);
    void paintEvent(QPaintEvent *event);

private slots:
    void onSaveScreen(); //保存至剪切板
    void onCompleteShot();

private:
    QPixmap m_loadPixmap, m_capturePixmap;
    int m_screenwidth;
    int m_screenheight;
    // 保存确定选区的坐标点;
    QPoint m_beginPoint, m_endPoint, m_beginMovePoint, m_endMovePoint;
    QPainter m_painter;
    // 保存当前截图状态;
    CaptureState m_currentCaptureState;
    // 当前选择区域矩形;
    QRect m_currentSelectRect;
    // 选中矩形8个顶点小矩形;
    QRect m_topLeftRect, m_topRightRect, m_bottomLeftRect, m_bottomRightRect;
    QRect m_leftCenterRect, m_topCenterRect, m_rightCenterRect, m_bottomCenterRect;
    // 当前鼠标所在顶点状态;
    StretchRectState m_stretchRectState;

protected:
    virtual void contextMenuEvent(QContextMenuEvent *event);
};

#endif // CAPTURESCREEN_H