qt随记：截屏简单实现

通过qt实现一些截屏功能

qt截图API

qApp->primaryScreen()->grabWindow(0);

画框选API

 void drawRect(int x1, int y1, int w, int h);

鼠标事件API

  void mousePressEvent(QMouseEvent *event);
  void mouseReleaseEvent(QMouseEvent *event);
  void mouseDoubleClickEvent(QMouseEvent *event);
  void mouseMoveEvent(QMouseEvent *event);

获取鼠标点

void CaptureWgt::mousePressEvent(QMouseEvent *event)
{
    m_start = event->pos();
}

void CaptureWgt::mouseReleaseEvent(QMouseEvent *event)
{
    m_end = event->pos();
}

绘制鼠标框选区域

painter.drawRect(m_start.x(),m_start.y(),m_end.x()-m_start.x(),m_end.y()-m_start.y());

保存到剪贴板

void CaptureWgt::capture()
{
    int x = m_end.x() < m_start.x() ?  m_end.x() :  m_start.x();
    int y = m_end.y() < m_start.y() ?  m_end.y() :  m_start.y();
    m_pix = m_pix.copy(x,y,qAbs(m_end.x()-m_start.x()),qAbs(m_end.y()-m_start.y()));
}

头文件

#ifndef CAPTUREWGT_H
#define CAPTUREWGT_H

#include 
#include 
#include 

class ToolWgt;
class CaptureWgt : public QWidget
{
    Q_OBJECT

public:
    CaptureWgt(QWidget *parent = nullptr);
    ~CaptureWgt();
protected:
    void paintEvent(QPaintEvent*);
    void mousePressEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);
    void mouseDoubleClickEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent *event);
    void keyPressEvent(QKeyEvent *event);
    void updateToolWgt();
    void capture();
private slots:
    void slot_check();
    void slot_close();
    void slot_download();
private:
    bool    m_isGrap{false};
    QPointF m_start;
    QPointF m_end;
    QPointF m_startTemp;
    QPointF m_endTemp;
    QPixmap m_pix;
    ToolWgt* m_toolWgt;
};
#endif // CAPTUREWGT_H

源文件

#include "capturewgt.h"
#include "toolwgt.h"
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

CaptureWgt::CaptureWgt(QWidget *parent)
    : QWidget(parent)
{
    setWindowFlags(Qt::FramelessWindowHint |Qt::WindowStaysOnTopHint|Qt::Tool);
    setAttribute(Qt::WA_TranslucentBackground);

    m_toolWgt = new ToolWgt(this);
    connect(m_toolWgt,&ToolWgt::sig_check,this,&CaptureWgt::slot_check);
    connect(m_toolWgt,&ToolWgt::sig_close,this,&CaptureWgt::slot_close);
    connect(m_toolWgt,&ToolWgt::sig_download,this,&CaptureWgt::slot_download);

    m_pix = qApp->primaryScreen()->grabWindow(0);
    this->grabKeyboard();
    m_toolWgt->move((m_pix.width()-m_toolWgt->width()),0);
}

CaptureWgt::~CaptureWgt()
{

}

void CaptureWgt::paintEvent(QPaintEvent* event)
{
    QPainter painter(this);
    if(m_isGrap){
        painter.drawRect(this->rect());
    }else{
        painter.drawPixmap(0,0,m_pix);
        QPen pen = painter.pen();
        pen.setColor(Qt::red);
        painter.setRenderHint(QPainter::Antialiasing);
        if(!m_start.isNull() && !m_end.isNull()){
            pen.setWidth(1);
            painter.setPen(pen);
            painter.drawRect(m_start.x(),m_start.y(),m_end.x()-m_start.x(),m_end.y()-m_start.y());
        }else{
            pen.setWidth(pen.width()+3);
            painter.setPen(pen);
            painter.drawRect(0,0,width()-3,height()-5);
        }
    }
    event->accept();

}

void CaptureWgt::mousePressEvent(QMouseEvent *event)
{
    m_startTemp = m_start;
    m_endTemp = m_end;

    m_isGrap = true;
    m_toolWgt->hide();
    this->repaint();
    m_pix = qApp->primaryScreen()->grabWindow(0);
    m_isGrap = false;

    m_start = event->pos();
    m_end  = QPointF();
    updateToolWgt();
}

void CaptureWgt::mouseReleaseEvent(QMouseEvent *event)
{
    m_end = event->pos();
    if(qAbs( m_start.x() - m_end.x()) < 1 && qAbs( m_start.x() - m_end.x()) < 1){
        m_end   = m_endTemp;
        m_start = m_startTemp;
    }
    update();
    updateToolWgt();
}

void CaptureWgt::mouseDoubleClickEvent(QMouseEvent *event)
{
    event->accept();
    slot_check();
    m_toolWgt->close();
}

void CaptureWgt::mouseMoveEvent(QMouseEvent *event)
{
    m_end = event->pos();
    update();
    m_toolWgt->hide();
}

void CaptureWgt::keyPressEvent(QKeyEvent *event)
{
    if(event->key() == Qt::Key_Space &&
            event->modifiers() == (Qt::AltModifier|Qt::ControlModifier) ){
        slot_download();
    }
    else if(event->key() == Qt::Key_Space &&
            event->modifiers() == (Qt::ShiftModifier|Qt::ControlModifier) ){
        slot_check();
    }
    event->accept();
}

void CaptureWgt::updateToolWgt()
{
    if(m_start.isNull() || m_end.isNull()){
        m_toolWgt->move((m_pix.width()-m_toolWgt->width()),0);
        return;
    }
    if(m_start == m_end){
        m_toolWgt->hide();
        return;
    }
    int x = m_end.x() > m_start.x() ?  m_end.x() :  m_start.x();
    int y = m_end.y() > m_start.y() ?  m_end.y() :  m_start.y();
    if(y+m_toolWgt->height() > m_pix.height()){
        y = 0;
    }
    m_toolWgt->setGeometry(x-m_toolWgt->width(),y,m_toolWgt->width(),m_toolWgt->height());
    m_toolWgt->show();
}

void CaptureWgt::capture()
{
    int x = m_end.x() < m_start.x() ?  m_end.x() :  m_start.x();
    int y = m_end.y() < m_start.y() ?  m_end.y() :  m_start.y();
    m_pix = m_pix.copy(x,y,qAbs(m_end.x()-m_start.x()),qAbs(m_end.y()-m_start.y()));
}

void CaptureWgt::slot_check()
{
    this->capture();
    if(false == m_pix.isNull()){
        QClipboard* pClipboard = QApplication::clipboard();
        pClipboard->setPixmap(m_pix);
    }
    this->close();
}

void CaptureWgt::slot_close()
{
    this->close();
}

void CaptureWgt::slot_download()
{
    do{
        QString fileName = QStandardPaths::writableLocation(QStandardPaths::PicturesLocation)
                + QString("/IMG_")+QDateTime::currentDateTime().toString("yyyyMMddhhmmss")+QString(".jpg");
        fileName = QFileDialog::getSaveFileName(this, tr("Save File"),
                                                fileName,
                                                tr("Images (*.png  *.jpg)"));
        if(fileName.isEmpty()){
            break;
        }
        this->capture();
        if(m_pix.isNull()){
            break;
        }
        m_pix.save(fileName);
    }while(0);
    this->close();
}

按钮

#ifndef TOOLWGT_H
#define TOOLWGT_H

#include 

class QToolButton;
class ToolWgt : public QWidget
{
    Q_OBJECT
public:
    explicit ToolWgt(QWidget *parent = nullptr);
    QToolButton* create(QString res);
signals:
   void sig_check();
   void sig_close();
   void sig_download();
};

#endif // TOOLWGT_H

#include "toolwgt.h"
#include 
#include 
#include 

ToolWgt::ToolWgt(QWidget *parent)
    : QWidget{parent}
{

    QHBoxLayout* pLayout = new QHBoxLayout(this);
    pLayout->setContentsMargins(5,5,0,5);
    pLayout->addStretch();

    QToolButton* pBtn = create(QStringLiteral(":/img/download.svg"));
    pBtn->setToolTip(QStringLiteral("保存选中区域"));
    connect(pBtn,&QToolButton::clicked,this,[&]{
        emit sig_download();
        this->close();
    });
    pLayout->addWidget(pBtn);

    pBtn = create(QStringLiteral(":/img/close.svg"));
    pBtn->setToolTip(QStringLiteral("取消本次截屏"));
    connect(pBtn,&QToolButton::clicked,this,[&]{
        emit sig_close();
        this->close();
    });
    pLayout->addWidget(pBtn);

    pBtn = create(QStringLiteral(":/img/check.svg"));
    pBtn->setToolTip(QStringLiteral("完成"));
    connect(pBtn,&QToolButton::clicked,this,[&]{
        emit sig_check();
        this->close();
    });
    pLayout->addWidget(pBtn);
    adjustSize();
}

QToolButton *ToolWgt::create(QString res)
{
    QToolButton* pBtn = new QToolButton;
    pBtn->setIcon(QIcon(res));
    pBtn->setIconSize(QSize(48,48));
    pBtn->setFixedSize(48,48);
    pBtn->setToolButtonStyle(Qt::ToolButtonIconOnly);
    pBtn->setAutoRaise(true);
    return pBtn;
}