软件实现拖动截屏并顶置截屏结果，将最后截图复制到剪切板。可用于数据对比或其它场合。

   软件运行流程为：快捷键-》抓屏-》截图-》顶置-》复制结果。

   开始时没注意内存，截屏耗费大量内存，后优化后空闲时内存使用在4M左右。

   以下为代码：

  

#-------------------------------------------------
# Ssot.pro
# Project created by QtCreator 2013-11-24T11:01:06
#
#-------------------------------------------------
QT       += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = Ssot
TEMPLATE = app
SOURCES += main.cpp\
        mainwindow.cpp \
    ctoplabel.cpp \
    aboutdialog.cpp
HEADERS  += mainwindow.h \
    ctoplabel.h \
    aboutdialog.h
RESOURCES += \
    resource.qrc
RC_FILE  += \
    info.rc
OTHER_FILES += \
    info.rc \
    readme.txt


mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include
#include
#include"aboutdialog.h"
#include"ctoplabel.h"
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();
    struct IDStruct
    {
        WId id;
        CTopLabel* pTopLabel;
    };
private:
    //托盘图标
    //注册热键
    void registerGlobalKey();
    //开始截图热键ID
    int hotkeyShotBgId;
    QVector topLabelList;
    //初始化托盘;
    void initTray();
    //是否正在截图
    bool isShotting;
    //本地事件
    bool nativeEvent(const QByteArray &eventType, void *message, long *result);
    AboutDialog* aboutDialog;
    QSystemTrayIcon* trayIcon;
private slots:
    //开始截图
    void hotkeyShotBgReceived();
    void clearShots();
public slots:
    //关闭
    void clearShot(WId i);
    //设置isShotting为false，允许再次截屏
    void allowShot();
    //关于
    void doAboutAction();
signals:
    //开始截屏热键按下
    void hotkeyShotBgPressed();
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include
#include"aboutdialog.h"
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    topLabelList.clear();
    isShotting=false;
    registerGlobalKey();
    initTray();
    aboutDialog =new AboutDialog;
    connect(this,SIGNAL(hotkeyShotBgPressed()),SLOT(hotkeyShotBgReceived()));
    trayIcon->showMessage(tr("截图置顶 v1.0.1"),"程序已启动,按\"Shift+Z\"后拖动鼠标！");
    trayIcon->setToolTip(tr("按\"Shift+Z\"后拖动鼠标"));
}
MainWindow::~MainWindow()
{
    if(UnregisterHotKey(HWND(this->winId()), hotkeyShotBgId))
    {
        qDebug("SHIFT+Z IS UNREGISTED");
    }
    clearShots();
}
void MainWindow::registerGlobalKey()
{
    hotkeyShotBgId =GlobalAddAtom(L"hotkeyShotBg") - 0xC000;
    if(RegisterHotKey((HWND(this->winId())), hotkeyShotBgId,MOD_SHIFT,0x5A))
    {
        qDebug("SHIFT+Z IS REGISTERED");
    }
}
bool MainWindow::nativeEvent(const QByteArray &eventType, void *message, long *result)
{
    if(eventType=="windows_generic_MSG")
    {
        //qDebug("This is windows MSG");
        MSG* msg=static_cast(message);
        if(msg->message==WM_HOTKEY)
        {
            UINT fuModifiers = (UINT) LOWORD(msg->lParam);  // 模式
            UINT uVirtKey = (UINT) HIWORD(msg->lParam);     // 键值
           // qDebug("This is HotKey!");
            if(fuModifiers==MOD_SHIFT&&uVirtKey==0x5A)
            {
                emit hotkeyShotBgPressed();
                qDebug("SHIFT+Z is Pressed");
            }
            return true;
         }
    }
 return  false;
}
void MainWindow::hotkeyShotBgReceived()
{
     //如果正在截图，则不处理
    if(!isShotting)
    {
                                                                                                                                                                                                                                                                     
        CTopLabel* fullScreenLabel=new CTopLabel;
                                                                                                                                                                                                                                                                     
        //用于传递窗口指针及WId
        IDStruct idStruct;
        idStruct.id=fullScreenLabel->winId();
        idStruct.pTopLabel=fullScreenLabel;
        topLabelList.append(idStruct);
                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                     
        //窗口发出关闭信号
        connect(fullScreenLabel,SIGNAL(meClosed(WId)),this,SLOT(clearShot(WId)));
        connect(fullScreenLabel,SIGNAL(shotted()),this,SLOT(allowShot()));
        fullScreenLabel->showFullScreen();
    }
    isShotting=true;
}
void MainWindow::initTray()
{
    trayIcon=new QSystemTrayIcon(this);
    trayIcon->setIcon(QIcon(":/icon/resource/icon.png"));
    QMenu* trayMenu=new QMenu;
    QAction* exitAction=new QAction(tr("退出 (&X)"),trayMenu);
    QAction* aboutAciton=new QAction(tr("关于 (&A)"),trayMenu);
    QAction* clearAciton=new QAction(tr("清除 (&C)"),trayMenu);
    trayMenu->addAction(clearAciton);
    connect(clearAciton,SIGNAL(triggered()),this,SLOT(clearShots()));
    trayMenu->addSeparator();
    trayMenu->addAction(aboutAciton);
    connect(aboutAciton,SIGNAL(triggered()),this,SLOT(doAboutAction()));
    trayMenu->addAction(exitAction);
    connect(exitAction,SIGNAL(triggered()),this,SLOT(close()));
    trayIcon->setContextMenu(trayMenu);
    trayIcon->show();
}
void MainWindow::clearShots()
{
    while(topLabelList.count()>0)
    {
        delete topLabelList.first().pTopLabel;
        topLabelList.first().pTopLabel=NULL;
        topLabelList.removeFirst();
    }
}
void MainWindow::clearShot(WId id)
{
    qDebug()<setText(":/icon/readme.txt",true);
    aboutDialog->setWindowTitle(tr("关于截图置顶 v1.0.1"));
    aboutDialog->setLogo(":/icon/resource/about-logo.png");
    aboutDialog->setInfo("
截图置顶 v1.0.1查看源代码
by pansinm[email protected]
");
    aboutDialog->show();
}

ctoplabel.h

//截屏窗口
#ifndef CTOPLABEL_H
#define CTOPLABEL_H
#include 
class CTopLabel : public QLabel
{
    Q_OBJECT
public:
    explicit CTopLabel(QWidget *parent = 0);
    //截图状态
    enum shotState{initShot,beginShot,finishShot};
                                                                                                                                                                                                                                                           
    //winId
    void setLabelId(WId id){labelId=id;}
    ~CTopLabel();
signals:
    //发送关闭信号
    void meClosed(WId);
    //完成截屏信号
    void shotted();
private:
    int labelId;
    //全屏Pixmap
    QPixmap fullScreenPixmap;
    //截图pixmap
    QPixmap resultPixmap;
    //截图状态
    shotState currentState;
    //鼠标起始点
    QPoint beginPoint;
    //终点
    QPoint endPoint;
    //鼠标拖动矩形
    QRect shotRect;
    //是否正在截图
    bool isShot;
    //左键是否按下
    bool isPressed;
    //拖动点
    QPoint dragPosition;
    void paintEvent(QPaintEvent *);
    void mousePressEvent(QMouseEvent *ev);
    void mouseMoveEvent(QMouseEvent *ev);
    void mouseReleaseEvent(QMouseEvent *ev);
    void mouseDoubleClickEvent(QMouseEvent *);
};
#endif // CTOPLABEL_H

ctoplabel.cpp

#include "ctoplabel.h"
CTopLabel::CTopLabel(QWidget *parent) :
    QLabel(parent)
{
    setLabelId(this->winId());
    setAutoFillBackground(true);
    //当前状态设置为初始化
    currentState=initShot;
    //设置为正在截图
    isShot=true;
    //初始化
    beginPoint=QPoint(0,0);
    endPoint=QPoint(0,0);
    shotRect=QRect(0,0,0,0);
    //左键按下状态
    isPressed=false;
    //初始化窗口拖动点
    dragPosition=QPoint(-1,-1);
    //设置无边框，任务栏无图标，顶置
    setWindowFlags(Qt::FramelessWindowHint|Qt::Tool|Qt::WindowStaysOnTopHint);
    //抓取屏幕
    fullScreenPixmap = QPixmap::grabWindow(QApplication::desktop()->winId());
}
CTopLabel::~CTopLabel()
{
}
void CTopLabel::mousePressEvent(QMouseEvent *ev)
{
    if(ev->button()==Qt::LeftButton)
    {
        isPressed=true;
        if(isShot)
        {
            //正在截图时，改变状态及beginPoint
            beginPoint=ev->pos();
            qDebug()<globalPos()-this->pos();
        }
    }
}
void CTopLabel::mouseMoveEvent(QMouseEvent *ev)
{
    if(isPressed)
    {
        if(isShot)
        {
            currentState=beginShot;
            //截屏拖动时
            //qDebug()<<"isShot";
            endPoint=ev->pos();
            //根据拖动位置，计算截图区域
            //左上->右下
            if(beginPoint.x()右上
            else if(beginPoint.x()endPoint.y())
            {
                shotRect=QRect(beginPoint.x(),endPoint.y(),endPoint.x()-beginPoint.x(),beginPoint.y()-endPoint.y());
            }
            //右上->左下
            else if(beginPoint.x()>endPoint.x()&&beginPoint.y()左上
            else
            {
                shotRect=QRect(endPoint,beginPoint);
            }
            update();
        }
        else
        {
            //窗口移动
            move(ev->globalPos()-dragPosition);
        }
    }
}
void CTopLabel::mouseReleaseEvent(QMouseEvent *ev)
{
    if(ev->button()==Qt::LeftButton)
    {
        endPoint=ev->pos();
        //qDebug()<repaint();
                setGeometry(shotRect);
                emit shotted();
                //结果复制到剪切板
                QClipboard *clipboard=QApplication::clipboard();
                clipboard->setPixmap(resultPixmap);
            }
        }
        else
        {
            move(ev->globalPos()-dragPosition);
        }
    }
    isPressed=false;
}
void CTopLabel::mouseDoubleClickEvent(QMouseEvent *e)
{
    if(e->button()==Qt::LeftButton)
    {
        //关闭当前
        emit meClosed(labelId);
    }
}
void CTopLabel::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setFont(QFont("simsun",20));
    switch(currentState)
    {
    case initShot:
        painter.drawPixmap(0,0,fullScreenPixmap);
        painter.setPen(QPen(Qt::blue,1,Qt::SolidLine,Qt::FlatCap));//设置画笔
        break;
    case beginShot:
        painter.drawPixmap(0,0,fullScreenPixmap);
        painter.setPen(QPen(Qt::blue,1,Qt::SolidLine,Qt::FlatCap));//设置画笔
        painter.drawRect(shotRect);
        break;
    case finishShot:
        painter.drawPixmap(0,0,resultPixmap);
        painter.setPen(QPen(Qt::gray,1,Qt::SolidLine,Qt::FlatCap));//设置画笔
        painter.drawRect(0,0,resultPixmap.size().width()-1,resultPixmap.size().height()-1);
        //截图结果窗口
        break;
    }
}

aboutdialog.h

//这个是我原来做的关于对话框的一个模板，直接拿来用了
#ifndef ABOUTDIALOG_H
#define ABOUTDIALOG_H
#include 
#include
#include
#include
#include
class AboutDialog : public QDialog
{
    Q_OBJECT
public:
    explicit AboutDialog(QWidget *parent = 0);
    //如果为true，则text为文件名，文本框中加载文件内容（文本文件）
    void setText(const QString str,bool isFileName=false);
    //370x45图片
    void setLogo(const QString filename);
    void setInfo(const QString info);
    void setBackground(const QString styleSheet="default");
private:
    QLabel* label_Logo;
    QLabel* label_Info;
    QTextEdit* textEdit;
    QPushButton* btn_confirm;
    void init();
signals:
public slots:
    void openUrl(QString);
};
#endif // ABOUTDIALOG_H

aboutdialog.cpp

#include "aboutdialog.h"
#include
#include
#include
#include
#include
#include
#include
AboutDialog::AboutDialog(QWidget *parent) :
    QDialog(parent)
{
    init();
}
void AboutDialog::init()
{
    //标题栏不要按钮
    this->setWindowFlags(Qt::WindowTitleHint | Qt::CustomizeWindowHint);
    label_Logo=new QLabel;
    label_Logo->setMinimumSize(370,45);
    label_Info=new QLabel;
    label_Info->setMinimumSize(370,45);
    textEdit=new QTextEdit;
    textEdit->setMinimumSize(370,115);
    textEdit->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    textEdit->setReadOnly(true);
    btn_confirm=new QPushButton("确定");
    btn_confirm->setMinimumSize(75,25);
    QHBoxLayout* hlayout=new QHBoxLayout;
    hlayout->addStretch();
    hlayout->addWidget(btn_confirm);
    hlayout->setMargin(4);
    QVBoxLayout* vlayout=new QVBoxLayout;
    vlayout->addWidget(label_Logo);
    vlayout->addWidget(label_Info);
    vlayout->addWidget(textEdit);
    vlayout->addLayout(hlayout);
    vlayout->setMargin(0);
    setLayout(vlayout);
    this->setMinimumSize(370,254);
    this->setMaximumSize(370,254);
    setBackground();
    connect(btn_confirm,SIGNAL(clicked()),this,SLOT(hide()));
}
void AboutDialog::setLogo(const QString filename)
{
    QPixmap pixmap(filename);
    label_Logo->setPixmap(pixmap);
}
void AboutDialog::setInfo(const QString info)
{
    label_Info->setText(info);
    connect(label_Info,SIGNAL(linkActivated(QString)),this,SLOT(openUrl(QString)));
}
void AboutDialog::setText(const QString str, bool isFileName)
{
    if(isFileName==false)
        textEdit->setText(str);
    else if(isFileName==true)
    {
        QFile file(str);
        if(file.open(QIODevice::ReadOnly|QIODevice::Text))
        {
            QTextStream in(&file);
            QString s;
            s=in.readAll();
            textEdit->setText(s);
            file.close();
        }
    }
}
void AboutDialog::setBackground(const QString styleSheet)
{
    if(styleSheet=="default")
    {
        this->setStyleSheet("AboutDialog{background: rgb(238, 241, 255);}");
    }
    else
        setStyleSheet(styleSheet);
}
void AboutDialog::openUrl(QString url)
{
    QDesktopServices::openUrl(QUrl(url));
}

main.cpp

#include "mainwindow.h"
#include 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    //w.show();
    return a.exec();
}

resource.qrc


    
        resource/icon.png
        readme.txt
        resource/about-logo.png


以下为运行效果：

Qt实现截屏_第1张图片

Qt实现截屏_第2张图片

Qt实现截屏_第3张图片



  • QPixmap::grabWindow(QApplication::desktop()->winId())//用于抓取整个屏幕

  • 利用paintEve绘制拖动矩形，并将剪切结果绘制到窗口。

  • 截图完调整窗口大小前用repaint重绘窗口，否则有可能闪烁。

  • 关闭一个窗口时，用delete删除内存，否则内存会一直叠。

  • 截图完毕后用fullScreenPixmap.loadFromData(NULL)删除全屏pixmap，可释放几M的内存。

  • setWindowFlags(Qt::FramelessWindowHint|Qt::Tool|Qt::WindowStaysOnTopHint);可设置无边框，无任务栏图标，顶置窗口。


源代码地址为：https://github.com/pansinm/Ssot

程序下载地址：http://url.cn/K89Rrn