思路
首先我们先获取到当前桌面的完整图片,然后将其放到一个全屏的透明窗口之中,之后,我们在窗口上进行绘制矩形操作,然后获取到绘制的区域即可。
核心代码
新建一个screenview的界面,设置为全屏窗口模式
setWindowState(Qt::WindowActive|Qt::WindowFullScreen);
获取到桌面的完成图片,保存图片,之前我们已经知道如何获取全屏图片。
screen =QGuiApplication::primaryScreen();
if(const QWindow *window=windowHandle())
screen=window->screen();
if(!screen)
return ;
originalPixmap=screen->grabWindow(0);
重写四个方法paintEvent
,mousePressEvent
,mouseMoveEvent
,mouseReleaseEvent
,后面的3个鼠标方法,我们主要用来获取鼠标的位置,以便能够在绘制方法里头绘制出矩形区域。
//截图
void screenview::paintEvent(QPaintEvent *event){
painter.begin(this);
painter.setPen(QPen(Qt::red,2));
painter.drawPixmap(0,0,originalPixmap);
if(sx>=0&&sy>=0)
{
painter.drawRect(QRect(sx,sy,ex-sx,ey-sy));
}
painter.end();
}
void screenview::mousePressEvent(QMouseEvent *event)
{
if(event->button()==Qt::LeftButton){
sx=event->x();
sy=event->y();
startpoint=event->pos();
}
update();
}
void screenview::mouseMoveEvent(QMouseEvent *event){
ex=event->x();
ey=event->y();
endpoint=event->pos();
update();
}
void screenview::mouseReleaseEvent(QMouseEvent *event){
this->close();
ex=event->x();
ey=event->y();
//获取到区域截图
sourcePixmap=originalPixmap.copy(sx*Scale,sy*Scale,(ex-sx)*Scale,(ey-sy)*Scale);
}
完整代码
//screenview.h
#ifndef SCREENVIEW_H
#define SCREENVIEW_H
#include <QWidget>
#include <QPainter>
#include <QScreen>
#include <QWindow>
#include <QPixmap>
#include <QMouseEvent>
#include <QRubberBand>
#include <QDateTime>
#include <QLabel>
#include "editwindow.h"
#include "mainwindow.h"
//添加
class QRubberBand;
namespace Ui {
class screenview;
}
class screenview : public QWidget
{
Q_OBJECT
public:
screenview(QWidget *parent = nullptr,QList<QRect> *ListRect=nullptr,int screentype=0);
~screenview();
protected:
void paintEvent(QPaintEvent *event);
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
protected slots:
void mouseReleaseEvent(QMouseEvent *event);
void receiveData(QString str); //接收传递过来的数据的槽
private:
Ui::screenview *ui;
QPainter painter;
QPixmap originalPixmap;
QPixmap sourcePixmap;
QScreen *screen;
QRubberBand *rubberBand;
QPoint startpoint;
QPoint endpoint;
//记录鼠标位置
int sx,sy,ex,ey;
//记录矩形的大小
int rw,rh;
//截图类型
int shottype;
//固定截图的坐标
int fixedx,fixedy;
//固定大小的矩形
QRect fixedRect;
//窗口放大倍数
float Scale;
//保存所有的矩形
QList<QRect> *ListRect;
//当前选中的窗口
QRect CurrentWindow;
signals:
void senddata(QPixmap sourcePixmap);
};
#endif // SCREENVIEW_H
#include "screenview.h"
#include "ui_screenview.h"
screenview::screenview(QWidget *parent,QList<QRect> *listRect,int screentype)
:QWidget(parent),ui(new Ui::screenview)
{
ui->setupUi(this);
rubberBand=NULL;
shottype=screentype;
screen =QGuiApplication::primaryScreen();
if(const QWindow *window=windowHandle())
screen=window->screen();
if(!screen)
return ;
originalPixmap=screen->grabWindow(0);
//全屏窗口
setWindowState(Qt::WindowActive|Qt::WindowFullScreen);
//解决只有鼠标按下时才捕捉鼠标移动
setMouseTracking(true);
//获取系统设置的显示比例
float swidth=this->width();
float rwidth=originalPixmap.width();
Scale=rwidth/swidth;
ListRect=listRect;
}
screenview::~screenview()
{
delete ui;
}
//截图
void screenview::paintEvent(QPaintEvent *event){
painter.begin(this);
painter.setPen(QPen(Qt::red,2));
painter.drawPixmap(0,0,originalPixmap);
if(shottype==1)
{
//固定窗口截图
rw=300;
rh=200;
int fixx=(ex-rw/2)>0?(ex-rw/2):0;
int fixy=(ey-rh/2)>0?(ey-rh/2):0;
fixedRect=QRect(fixx,fixy,rw,rh);
painter.drawRect(fixedRect);
painter.setPen(QPen(Qt::black,2));
painter.drawText(fixx,fixy+rh+10,"F2调整大小");
}else if(shottype==0)
{
if(sx>=0&&sy>=0)
{
painter.drawRect(QRect(sx,sy,ex-sx,ey-sy));
}
}
painter.end();
}
void screenview::mousePressEvent(QMouseEvent *event)
{
if(event->button()==Qt::LeftButton){
sx=event->x();
sy=event->y();
startpoint=event->pos();
if(shottype==1){
this->close();
sourcePixmap=originalPixmap.copy(fixedRect.x()*Scale,fixedRect.y()*Scale,fixedRect.width()*Scale,fixedRect.height()*Scale);
emit senddata(sourcePixmap);
}
else if(shottype==2){
this->close();
sourcePixmap=originalPixmap.copy(CurrentWindow.x()*Scale,CurrentWindow.y()*Scale,CurrentWindow.width()*Scale,CurrentWindow.height()*Scale);
emit senddata(sourcePixmap);
}
}
update();
}
void screenview::mouseMoveEvent(QMouseEvent *event){
ex=event->x();
ey=event->y();
endpoint=event->pos();
update();
}
void screenview::mouseReleaseEvent(QMouseEvent *event){
this->close();
ex=event->x();
ey=event->y();
sourcePixmap=originalPixmap.copy(sx*Scale,sy*Scale,(ex-sx)*Scale,(ey-sy)*Scale);
//将获取到的图片内容发送到编辑窗口,可以直接保存到本地即可
emit senddata(sourcePixmap);
}