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QT实现截屏功能

分类： C/C++

2011-05-18 17:27:57

    最近因为需要开发一个类似QQ的截屏功能，花了不少的时间，开始的时候很多也不懂，不知道如何下手，在网上找了很多的资料，现已经实现了截屏，移动截屏选区，通过拖动选区的八个控制点来改变选区的大小。
    QT实现截屏的原理是，当点击截屏按钮（菜单栏上的截屏按钮）时，调用fullScreenWidget对象getFullScreenPixmap()方法，返回当前屏幕的QPixmap图片对象。在构造调用窗体的构造函数中，关联信号与槽，使其在点击“截屏”按钮发送信息给fullScreenWidget对象对应的槽函数，以便加载当前的背景图片。
connect(newAct,SIGNAL(triggered()),this,SLOT(screenshot()));
connect(this,SIGNAL(setPixmap(QPixmap)),fullWidget,SLOT(loadBackgroundPixmap(QPixmap)));
    在fullScreenWidget类中，主要是根据当前截屏的状态来实时的判断如果截取屏幕。我在类中定义了shotState枚举类型，用来判断当前截屏的状态。定义了QPoint beginPoint,endPoint,moveBeginPoint,moveEndPoint;四个对象主要用来记录开始，结束的截屏坐标。移动的开始，结束坐标。根据不同的截屏状态和这4个坐标点的值来计算截屏的区域。我的表达能力不太好，先把核心代码上面来。fullScreenWidget.h头文件代码如下：
  1. #ifndef FULLSCREENWIDGET_H
  2. #define FULLSCREENWIDGET_H

  4. #include <QWidget>
  5. #include <QPixmap>
  6. #include <QPoint>
  7. #include <QtGui>
  8. #include <QPainter>
  9. #include <QBrush>

  11. class fullScreenWidget : public QWidget{

  13.   Q_OBJECT
  14.   
  15.   public:
  16.   fullScreenWidget(); //构造函数
  17.   enum shotState{initShot,beginShot,finishShot,endShot,beginMoveShot,finishMoveShot,beginControl,finishControl}; //进行截屏的状态
  18.   //移动选区中的8个控制点，按照顺时针方向从左上控制点到左中控制点分配编号为1～8
  19.   enum controlPointEnum{moveControl0,moveControl1,moveControl2,moveControl3,moveControl4,moveControl5,moveControl6,moveControl7,moveControl8};
  20.   QPixmap getFullScreenPixmap(); //获取全屏的Pixmap
  21.   
  22.   public slots:
  23.   void loadBackgroundPixmap(const QPixmap &bgPixmap);//加载背景Pixmap槽函数
  24.   void loadBackgroundPixmap(const QPixmap &bgPixmap, int x, int y, int width, int height); //加载背景pixmap槽函数，设置x,y,width,height
  25.   void cancelSelectedRect(); //取消选择区域
  26.   void savePixmap(); //保选取行为的方法
  27.   
  28.   signals:
  29.   void finishPixmap(const QPixmap &finishPixmap); //完成切图后的图片,发送信号给连接者

  31.   private:
  32.   //选区框的8个点选取
  33.   QRect tlRect; //左上点
  34.   QRect trRect; //右上点
  35.   QRect blRect; //左下点
  36.   QRect brRect; //右下点
  37.   QRect tcRect; //上中点
  38.   QRect bcRect; //下中点
  39.   QRect lcRect;//左中点
  40.   QRect rcRect; //右中点

  42.   QPainter painter;
  43.   QPoint beginPoint,endPoint,moveBeginPoint,moveEndPoint;
  44.   QRect selectedRect; //选择区域
  45.   QPixmap loadPixmap,shotPixmap;
  46.   shotState currentShotState; //当前的截屏状态
  47.   controlPointEnum controlValue; //记录移动控制点的值
  48.   QAction *savePixmapAction; //保存图片行为
  49.   QAction *cancelAction; //取消选取行为
  50.   QAction *quitAction; //退出选取行为
  51.   QMenu *contextMenu; //选中区域右键菜单
  52.   int screenwidth; //整个屏幕的宽度
  53.   int screenheight; //整个屏幕的高度
  54.   int screenx; //选区的X
  55.   int screeny; //选区的Y
  56.   int tipWidth,tipHeight,infoWidth,infoHeight; //加载初始框的宽度，高度；显示坐标信息的宽度，高度
  57.   
  58.   QRect getSelectedRect(); //获取选取
  59.   QRect getRect(const QPoint &beginPoint, const QPoint &endPoint); //根据两个点获取选取坐标
  60.   void initFullScreenWidget(); //初始化抓全屏的相关参数
  61.   bool isInSelectedRect(const QPoint &point); //判断该点是否在选中区域
  62.   void initSelectedMenu();//初始化右键菜单
  63.   void drawTipsText(); //在屏幕上打印提示信息
  64.   void drawSelectedPixmap(void); //在屏幕上画选取的屏幕
  65.   void updateBeginEndPointValue(const QRect &rect); //当移动选取后，对beginPoint,endPoint坐标进行重新修改
  66.   void checkMoveEndPoint(); //对移动的选区进行判断
  67.   void draw8ControlPoint(const QRect &rect);
  68.   void updateMouseShape(const QPoint &point); //更新鼠标的当前状态
  69.   void updateMoveControlMouseShape(controlPointEnum controlValue);
  70.   controlPointEnum getMoveControlState(const QPoint &point); //获取移动控制点状态
  71.   QRect getMoveAllSelectedRect(void); //获取移动整个选中的选区
  72.   QRect getMoveControlSelectedRect(void);//获取移动控制点的选区
  73.   int getMinValue(int num1, int num2);//获取两个数中的最小值
  74.   void drawXYWHInfo(void); //打印选取的x,y,h,w值信息

  76.   //重写基类方法
  77.   void keyPressEvent(QKeyEvent *event);
  78.   void paintEvent(QPaintEvent *event);
  79.   void mousePressEvent(QMouseEvent *event);
  80.   void mouseReleaseEvent(QMouseEvent *event);
  81.   void mouseMoveEvent(QMouseEvent *event);
  82.   void mouseDoubleClickEvent(QMouseEvent *event);
  83.   void contextMenuEvent(QContextMenuEvent *event);
  84. };

  86. #endif
fullScreenWidget.cpp类的实现文件如下：
  1. #include "fullScreenWidget.h"
  2. fullScreenWidget::fullScreenWidget()
  3. {
  4.   setWindowState(Qt::WindowActive|Qt::WindowFullScreen);
  5.   tipWidth = 300; //温馨提示框的宽度
  6.   tipHeight = 100; //温馨提示框的高度
  7.   infoWidth = 100; //坐标信息框的宽度
  8.   infoHeight = 50; //坐标信息框的高度
  9.   initFullScreenWidget();
  10. }

  12. void fullScreenWidget::initSelectedMenu()
  13. {
  14.   savePixmapAction = new QAction(tr("保存选区"),this);
  15.   cancelAction = new QAction(tr("重选"),this);
  16.   quitAction = new QAction(tr("退出"),this);
  17.   contextMenu = new QMenu(this);

  19.   connect(savePixmapAction,SIGNAL(triggered()),this,SLOT(savePixmap()));
  20.   connect(cancelAction,SIGNAL(triggered()),this,SLOT(cancelSelectedRect()));
  21.   connect(quitAction,SIGNAL(triggered()),this,SLOT(hide()));
  22. }

  24. void fullScreenWidget::savePixmap()
  25. {
  26.   QString fileName;
  27.   fileName = QFileDialog::getSaveFileName(this,tr("保存图片"),QDir::currentPath(),tr("Images (*.jpg *.png *.bmp)"));
  28.   if(fileName.isNull())
  29.     return;
  30.   
  31.   shotPixmap.save(fileName);
  32.   hide();
  33. }

  35. void fullScreenWidget::loadBackgroundPixmap(const QPixmap &bgPixmap)
  36. {
  37.   int width,height;
  38.   width = QApplication::desktop()->size().width();
  39.   height = QApplication::desktop()->size().height();

  41.   loadBackgroundPixmap(bgPixmap,0,0,width,height);
  42. }

  44. void fullScreenWidget::loadBackgroundPixmap(const QPixmap &bgPixmap, int x, int y, int width, int height)
  45. {
  46.   loadPixmap = bgPixmap;
  47.   screenx = x;
  48.   screeny = y;
  49.   screenwidth = width;
  50.   screenheight = height;
  51.   initFullScreenWidget();
  52. }

  54. QPixmap fullScreenWidget::getFullScreenPixmap()
  55. {
  56.   initFullScreenWidget();
  57.   QPixmap result = QPixmap();
  58.   result = QPixmap::grabWindow(QApplication::desktop()->winId()); //抓取当前屏幕的图片
  59.   
  60.   return result;
  61. }

  63. void fullScreenWidget::paintEvent(QPaintEvent *event)
  64. {
  65.   QColor shadowColor;
  66.   shadowColor= QColor(0,0,0,100); //阴影颜色设置
  67.   painter.begin(this); //进行重绘

  69.   painter.setPen(QPen(Qt::blue,2,Qt::SolidLine,Qt::FlatCap));//设置画笔
  70.   painter.drawPixmap(screenx,screeny,loadPixmap); //将背景图片画到窗体上
  71.   painter.fillRect(screenx,screeny,screenwidth,screenheight,shadowColor); //画影罩效果

  73.   switch(currentShotState){
  74.     case initShot:
  75.       drawTipsText();
  76.       break;
  77.     case beginShot:
  78.     case finishShot:
  79.       selectedRect = getRect(beginPoint,endPoint); //获取选区
  80.       drawSelectedPixmap();
  81.       break;
  82.     case beginMoveShot:
  83.     case finishMoveShot:
  84.       selectedRect = getMoveAllSelectedRect(); //获取选区
  85.       drawSelectedPixmap();
  86.       break;
  87.     case beginControl:
  88.     case finishControl:
  89.       selectedRect = getMoveControlSelectedRect();
  90.       drawSelectedPixmap();
  91.       break;
  92.     default:
  93.       break;
  94.   }
  95.   drawXYWHInfo(); //打印坐标信息
  96.   painter.end(); //重绘结束
  97.   
  98.   if(currentShotState == finishMoveShot || currentShotState == finishControl){
  99.     updateBeginEndPointValue(selectedRect); //当移动完选区后，更新beginPoint,endPoint;为下一次移动做准备工作
  100.   }

  102. }

  104. void fullScreenWidget::keyPressEvent(QKeyEvent *event)
  105. {
  106.   if(event->key() == Qt::Key_Escape){
  107.     initFullScreenWidget();
  108.     hide();
  109.   }
  110. }

  112. void fullScreenWidget::mousePressEvent(QMouseEvent *event)
  113. {
  114.   //当开始进行拖动进行选择区域时,确定开始选取的beginPoint坐标
  115.   if(event->button() == Qt::LeftButton && currentShotState == initShot){
  116.     currentShotState = beginShot; //设置当前状态为beginShot状态
  117.     beginPoint = event->pos();
  118.   }
  119.   
  120.   //移动选区改变选区的所在位置
  121.   if(event->button() == Qt::LeftButton && isInSelectedRect(event->pos()) &&
  122.      getMoveControlState(event->pos()) == moveControl0){
  123.       currentShotState = beginMoveShot; //启用开始移动选取选项,beginMoveShot状态
  124.       moveBeginPoint = event->pos();
  125.   }
  126.   //移动控制点改变选区大小
  127.   if(event->button() == Qt::LeftButton && getMoveControlState(event->pos()) != moveControl0){
  128.     currentShotState = beginControl; //开始移动控制点
  129.     controlValue = getMoveControlState(event->pos());
  130.     moveBeginPoint = event->pos();
  131.   }
  132. }

  134. void fullScreenWidget::mouseReleaseEvent(QMouseEvent *event)
  135. {
  136.   if(event->button() == Qt::LeftButton && currentShotState == beginShot){
  137.     currentShotState = finishShot;
  138.     endPoint = event->pos();
  139.     update();
  140.   }

  142.   if(event->button() == Qt::LeftButton && currentShotState == beginMoveShot){
  143.     currentShotState = finishMoveShot;
  144.     moveEndPoint = event->pos();
  145.     update();
  146.   }

  148.   //当前状态为beginControl状态时，设置状态为finishControl
  149.   if(event->button() == Qt::LeftButton && currentShotState == beginControl){
  150.     currentShotState = finishControl;
  151.     moveEndPoint = event->pos();
  152.     update();
  153.   }
  154. }

  156. void fullScreenWidget::mouseMoveEvent(QMouseEvent *event)
  157. {
  158.   //当拖动时，动态的更新所选择的区域
  159.   if(currentShotState == beginShot){
  160.     endPoint = event->pos();
  161.     update();
  162.   }

  164.   //当确定选区后，对选区进行移动操作
  165.   if(currentShotState == beginMoveShot || currentShotState == beginControl){
  166.     moveEndPoint = event->pos();
  167.     update();
  168.   }

  170.   updateMouseShape(event->pos()); //修改鼠标的形状
  171.   setMouseTracking(true);
  172. }

  174. void fullScreenWidget::mouseDoubleClickEvent(QMouseEvent *event)
  175. {
  176.   if(currentShotState == finishShot || currentShotState == finishMoveShot || currentShotState == finishControl){
  177.     emit finishPixmap(shotPixmap); //当完成时发送finishPixmap信号
  178.     hide();
  179.   }
  180. }

  182. QRect fullScreenWidget::getRect(const QPoint &beginPoint, const QPoint &endPoint)
  183. {
  184.   int x,y,width,height;
  185.   width = qAbs(beginPoint.x() - endPoint.x());
  186.   height = qAbs(beginPoint.y() - endPoint.y());
  187.   x = beginPoint.x() < endPoint.x() ? beginPoint.x() : endPoint.x();
  188.   y = beginPoint.y() < endPoint.y() ? beginPoint.y() : endPoint.y();
  189.   
  190.   return QRect(x,y,width,height);
  191. }

  193. void fullScreenWidget::initFullScreenWidget()
  194. {
  195.     currentShotState = initShot;
  196.     controlValue = moveControl0;
  197.     beginPoint =QPoint(0,0);
  198.     endPoint = QPoint(0,0);
  199.     moveBeginPoint = QPoint(0,0);
  200.     moveEndPoint = QPoint(0,0);

  202.     tlRect = QRect(0,0,0,0); //左上点
  203.     trRect = QRect(0,0,0,0); //上右点
  204.     blRect = QRect(0,0,0,0); //左下点
  205.     brRect = QRect(0,0,0,0); //右下点
  206.     tcRect = QRect(0,0,0,0); //上中点
  207.     bcRect = QRect(0,0,0,0); //下中点
  208.     lcRect = QRect(0,0,0,0); //左中点
  209.     rcRect = QRect(0,0,0,0); //右中点

  211.     setCursor(Qt::CrossCursor);
  212. }

  214. bool fullScreenWidget::isInSelectedRect(const QPoint &point)
  215. {
  216.   int x,y;
  217.   QRect selectedRect;
  218.   if(currentShotState == initShot || currentShotState == beginShot)
  219.     return false;

  221.   selectedRect = getSelectedRect();
  222.   x = point.x();
  223.   y = point.y();
  224.   
  225.   return selectedRect.contains(x,y);
  226. }

  228. void fullScreenWidget::cancelSelectedRect()
  229. {
  230.   initFullScreenWidget();
  231.   update(); //进行重绘，将选取区域去掉
  232. }

  234. void fullScreenWidget::contextMenuEvent(QContextMenuEvent *event)
  235. {
  236.   initSelectedMenu();

  238.   if(isInSelectedRect(event->pos())){
  239.     contextMenu->addAction(savePixmapAction);
  240.   }
  241.   else{
  242.     contextMenu->addAction(cancelAction);
  243.     contextMenu->addAction(quitAction);
  244.   }

  246.   contextMenu->exec(event->pos());
  247. }

  249. void fullScreenWidget::drawTipsText()
  250. {
  251.   int x = (screenwidth - tipWidth)/2;
  252.   int y = (screenheight - tipHeight)/2;
  253.   QColor color = QColor(100,100,100,200);
  254.   QRect rect = QRect(x,y,tipWidth,tipHeight);
  255.   QString strTipsText = QString(tr("温馨提示\n鼠标拖动进行截屏;截屏区域内右键保存;\n截屏区域外右键取消;ESC退出;"));

  257.   painter.fillRect(rect,color);
  258.   painter.setPen(QPen(Qt::white));//设置画笔的颜色为白色
  259.   painter.drawText(rect,Qt::AlignCenter,strTipsText);

  261. }

  263. QRect fullScreenWidget::getSelectedRect()
  264. {
  265.   if(currentShotState == beginMoveShot){
  266.      return getMoveAllSelectedRect();
  267.   }
  268.   else if(currentShotState == beginControl){
  269.      return getMoveControlSelectedRect();
  270.   }
  271.   else{
  272.     return getRect(beginPoint,endPoint);
  273.   }
  274. }

  276. void fullScreenWidget::updateBeginEndPointValue(const QRect &rect)
  277. {
  278.   beginPoint = rect.topLeft();
  279.   endPoint = rect.bottomRight();
  280.  
  281.   moveBeginPoint = QPoint(0,0);
  282.   moveEndPoint = QPoint(0,0);
  283. }

  285. void fullScreenWidget::checkMoveEndPoint()
  286. {
  287.   int x,y;
  288.   QRect selectedRect = getRect(beginPoint, endPoint);
  289.   QPoint bottomRightPoint = selectedRect.bottomRight();
  290.   x = moveEndPoint.x() - moveBeginPoint.x();
  291.   y = moveEndPoint.y() - moveBeginPoint.y();

  293.   if(x + selectedRect.x() < 0){ //当移动后X坐标小于零时，则出现选区丢失，则计算出moveEndPoint的X最大坐标值，进行赋值
  294.     moveEndPoint.setX(qAbs(selectedRect.x()-moveBeginPoint.x()));
  295.   }

  297.   if(y + selectedRect.y() < 0){ //当移动后Y坐标小于零时，则出现选区丢失，则计算出moveEndPoint的Y最大坐标值，进行赋值
  298.     moveEndPoint.setY(qAbs(selectedRect.y() - moveBeginPoint.y()));
  299.   }

  301.   if(x + bottomRightPoint.x() > screenwidth){ //当移动选区后，出现超出整个屏幕的右面时，设置moveEndPoint的X的最大坐标
  302.     moveEndPoint.setX(screenwidth - bottomRightPoint.x() + moveBeginPoint.x());
  303.   }

  305.   if(y + bottomRightPoint.y() > screenheight){ //当移动选区后，出现超出整个屏幕的下面时，设置moveEndPoint的Y的最大坐标值
  306.     moveEndPoint.setY(screenheight - bottomRightPoint.y() + moveBeginPoint.y());
  307.   }
  308. }

  310. void fullScreenWidget::draw8ControlPoint(const QRect &rect)
  311. {
  312.   int x,y;
  313.   QColor color= QColor(0,0,255); //画点的颜色设置
  314.   QPoint tlPoint = rect.topLeft(); //左上点
  315.   QPoint trPoint = rect.topRight(); //右上点
  316.   QPoint blPoint = rect.bottomLeft(); //左下点
  317.   QPoint brPoint = rect.bottomRight(); //右下点
  318.   
  319.   x = (tlPoint.x()+trPoint.x())/2;
  320.   y = tlPoint.y();
  321.   QPoint tcPoint = QPoint(x,y);

  323.   x = (blPoint.x()+brPoint.x())/2;
  324.   y = blPoint.y();
  325.   QPoint bcPoint = QPoint(x,y);

  327.   x = tlPoint.x();
  328.   y = (tlPoint.y()+blPoint.y())/2;
  329.   QPoint lcPoint = QPoint(x,y);

  331.   x = trPoint.x();
  332.   y = (trPoint.y()+brPoint.y())/2;
  333.   QPoint rcPoint = QPoint(x,y);

  335.   tlRect = QRect(tlPoint.x()-2,tlPoint.y()-2,6,6); //左上点
  336.   trRect = QRect(trPoint.x()-2,trPoint.y()-2,6,6); //右上点
  337.   blRect = QRect(blPoint.x()-2,blPoint.y()-2,6,6); //左下点
  338.   brRect = QRect(brPoint.x()-2,brPoint.y()-2,6,6); //右下点
  339.   tcRect = QRect(tcPoint.x()-2,tcPoint.y()-2,6,6); //上中点
  340.   bcRect = QRect(bcPoint.x()-2,bcPoint.y()-2,6,6); //下中点
  341.   lcRect = QRect(lcPoint.x()-2,lcPoint.y()-2,6,6);//左中点
  342.   rcRect = QRect(rcPoint.x()-2,rcPoint.y()-2,6,6); //右中点

  344.   painter.fillRect(tlRect,color);
  345.   painter.fillRect(trRect,color);
  346.   painter.fillRect(blRect,color);
  347.   painter.fillRect(brRect,color);
  348.   painter.fillRect(tcRect,color);
  349.   painter.fillRect(bcRect,color);
  350.   painter.fillRect(lcRect,color);
  351.   painter.fillRect(rcRect,color);
  352. }

  354. void fullScreenWidget::updateMouseShape(const QPoint &point)
  355. {
  356.   switch(currentShotState){
  357.     case initShot:
  358.     case beginShot:
  359.       setCursor(Qt::CrossCursor);
  360.       break;
  361.     case beginMoveShot:
  362.       setCursor(Qt::OpenHandCursor);
  363.       break;
  364.     case finishShot:
  365.     case finishMoveShot:
  366.     case finishControl:
  367.       if(getSelectedRect().contains(point))
  368.         setCursor(Qt::OpenHandCursor);
  369.       else
  370.         updateMoveControlMouseShape(getMoveControlState(point));
  371.       break;
  372.     case beginControl:
  373.       updateMoveControlMouseShape(controlValue); //调用函数对移动8个控制点进行鼠标状态的改变
  374.       break;
  375.     default:
  376.       setCursor(Qt::ArrowCursor);
  377.       break;
  378.   }
  379. }

  381. void fullScreenWidget::updateMoveControlMouseShape(controlPointEnum controlValue){
  382.   switch(controlValue){
  383.     case moveControl1:
  384.     case moveControl5:
  385.       setCursor(Qt::SizeFDiagCursor);
  386.       break;
  387.     case moveControl2:
  388.     case moveControl6:
  389.       setCursor(Qt::SizeVerCursor);
  390.       break;
  391.     case moveControl3:
  392.     case moveControl7:
  393.       setCursor(Qt::SizeBDiagCursor);
  394.       break;
  395.     case moveControl4:
  396.     case moveControl8:
  397.       setCursor(Qt::SizeHorCursor);
  398.       break;
  399.     default:
  400.       setCursor(Qt::ArrowCursor);
  401.       break;
  402.   }
  403. }

  405. fullScreenWidget::controlPointEnum fullScreenWidget::getMoveControlState(const QPoint &point)
  406. {
  407.   fullScreenWidget::controlPointEnum result = moveControl0;
  408.   if(currentShotState == initShot || currentShotState == beginShot) {
  409.     result = moveControl0;
  410.   }
  411.   else if(tlRect.contains(point)){
  412.     result = moveControl1;
  413.   }
  414.   else if(tcRect.contains(point)){
  415.     result = moveControl2;
  416.   }
  417.   else if(trRect.contains(point)){
  418.     result = moveControl3;
  419.   }
  420.   else if(rcRect.contains(point)){
  421.     result = moveControl4;
  422.   }
  423.   else if(brRect.contains(point)){
  424.     result = moveControl5;
  425.   }
  426.   else if(bcRect.contains(point)){
  427.     result = moveControl6;
  428.   }
  429.   else if(blRect.contains(point)){
  430.     result = moveControl7;
  431.   }
  432.   else if(lcRect.contains(point)){
  433.     result = moveControl8;
  434.   }
  435.   else{
  436.     result = moveControl0;
  437.   }

  439.   return result;
  440. }

  442. QRect fullScreenWidget::getMoveAllSelectedRect(void)
  443. {
  444.   QRect result;
  445.   QPoint tmpBeginPoint,tmpEndPoint;
  446.   int moveX,moveY;
  447.   checkMoveEndPoint(); //对移动选区进行判断，当移动的选区超出边界，则停止移动
  448.   moveX = moveEndPoint.x() - moveBeginPoint.x();
  449.   moveY = moveEndPoint.y() - moveBeginPoint.y();
  450.   tmpBeginPoint.setX(beginPoint.x() + moveX);
  451.   tmpBeginPoint.setY(beginPoint.y() + moveY);
  452.   tmpEndPoint.setX(endPoint.x() + moveX);
  453.   tmpEndPoint.setY(endPoint.y() + moveY);

  455.   result = getRect(tmpBeginPoint, tmpEndPoint);
  456.   return result;
  457. }

  459. QRect fullScreenWidget::getMoveControlSelectedRect(void)
  460. {
  461.   int x,y,w,h;
  462.   QRect rect = getRect(beginPoint,endPoint);
  463.   QRect result;
  464.   switch(controlValue){
  465.     case moveControl1:
  466.       result = getRect(rect.bottomRight(),moveEndPoint);
  467.       return result;
  468.       break;
  469.     case moveControl2:
  470.       x = rect.x();
  471.       y = getMinValue(moveEndPoint.y(),rect.bottomLeft().y());
  472.       w = rect.width();
  473.       h = qAbs(moveEndPoint.y() - rect.bottomRight().y());
  474.       break;
  475.     case moveControl3:
  476.       result = getRect(rect.bottomLeft(),moveEndPoint);
  477.       return result;
  478.       break;
  479.     case moveControl4:
  480.       x = getMinValue(rect.x(),moveEndPoint.x());
  481.       y = rect.y();
  482.       w = qAbs(rect.bottomLeft().x() - moveEndPoint.x());
  483.       h = rect.height();
  484.       break;
  485.     case moveControl5:
  486.       result = getRect(rect.topLeft(),moveEndPoint);
  487.       return result;
  488.       break;
  489.     case moveControl6:
  490.       x = rect.x();
  491.       y = getMinValue(rect.y(),moveEndPoint.y());
  492.       w = rect.width();
  493.       h = qAbs(moveEndPoint.y() - rect.topLeft().y());
  494.       break;
  495.     case moveControl7:
  496.       result = getRect(moveEndPoint,rect.topRight());
  497.       return result;
  498.       break;
  499.     case moveControl8:
  500.       x = getMinValue(moveEndPoint.x(),rect.bottomRight().x());
  501.       y = rect.y();
  502.       w = qAbs(rect.bottomRight().x() - moveEndPoint.x());
  503.       h = rect.height();
  504.       break;
  505.     default:
  506.       result = getRect(beginPoint,endPoint);
  507.       return result;
  508.       break;
  509.   }

  511.   return QRect(x,y,w,h); //获取选区
  512. }

  514. int fullScreenWidget::getMinValue(int num1, int num2)
  515. {
  516.   return num1<num2?num1:num2;
  517. }

  519. void fullScreenWidget::drawSelectedPixmap(void)
  520. {
  521.   painter.drawRect(selectedRect); //画选中的矩形框
  522.   shotPixmap = loadPixmap.copy(selectedRect); //更新选区的Pixmap
  523.   if(selectedRect.width() > 0 && selectedRect.height()){
  524.     painter.drawPixmap(selectedRect.topLeft(),shotPixmap); //画选中区域的图片
  525.   }
  526.   draw8ControlPoint(selectedRect); //画出选区的8个控制点
  527. }

  529. void fullScreenWidget::drawXYWHInfo(void)
  530. {
  531.   int x,y;
  532.   QColor color = QColor(239,234,228,200);
  533.   QRect rect;
  534.   QString strTipsText;
  535.   switch(currentShotState){
  536.     case beginShot:
  537.     case finishShot:
  538.     case beginMoveShot:
  539.     case finishMoveShot:
  540.     case beginControl:
  541.     case finishControl:
  542.       x = selectedRect.x() + 5;
  543.       y = selectedRect.y() > infoHeight ? selectedRect.y()-infoHeight:selectedRect.y();
  544.       rect = QRect(x,y,infoWidth,infoHeight);
  545.       strTipsText = QString(tr(" 坐标信息\n x:%1 y:%2\n w:%3 h:%4")).arg(selectedRect.x(),4).arg(selectedRect.y(),4)
  546.                       .arg(selectedRect.width(),4).arg(selectedRect.height(),4);
  547.     painter.fillRect(rect,color);
  548.     painter.setPen(QPen(Qt::black));//设置画笔的颜色为黑色
  549.     painter.drawText(rect,Qt::AlignLeft|Qt::AlignVCenter,strTipsText);
  550.     break;
  551.     default:
  552.     break;
  553.   }
  554. }
    您可以下载下来，进行测试使用。解压文件后，使用qtcreator工具进行加载screenshot.pro文件。执行qmake,build,run。即可。
    注：因我提供的源代码在ubuntu操作系统上编写，如果您使用的是windows操作系统，可能需要qtcreator修改字符集为uft-8即可。本代码使用的是qt4.6.2进行编译，使用emacs编辑器进行编写。
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给主人留下些什么吧！~~

mzero0072014-03-12 10:39:09

运行了一下觉得很好哎。。。谢谢楼主分享，我会好好研究的、、、

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