Qt 之 实现简单截图功能（二）

#include "capturescreen.h" #include <QApplication> #include <QDesktopWidget> #include <QMouseEvent> CaptureScreen::CaptureScreen(QWidget *parent) : QWidget(parent) , m_currentCaptureState(initCapture) { initWindow(); loadBackgroundPixmap(); } CaptureScreen::~CaptureScreen() { } void CaptureScreen::initWindow() { this->setMouseTracking(true); // 由于存在类似QQ这样界面始终显示在最顶层，设置属性 Qt::WindowStaysOnTopHint; this->setWindowFlags(Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint); setWindowState(Qt::WindowActive | Qt::WindowFullScreen); this->setMouseTracking(true); } void CaptureScreen::loadBackgroundPixmap() { m_loadPixmap = QPixmap::grabWindow(QApplication::desktop()->winId()); //抓取当前屏幕的图片; m_screenwidth = m_loadPixmap.width(); m_screenheight = m_loadPixmap.height(); } void CaptureScreen::mousePressEvent(QMouseEvent *event) { if (event->button() == Qt::LeftButton && m_currentCaptureState == initCapture) { m_currentCaptureState = beginCaptureImage; m_beginPoint = event->pos(); } else if (event->button() == Qt::LeftButton && isPressPointInSelectRect(event->pos())) { m_currentCaptureState = beginMoveCaptureArea; setCursor(Qt::SizeAllCursor); m_beginMovePoint = event->pos(); } return QWidget::mousePressEvent(event); } void CaptureScreen::mouseMoveEvent(QMouseEvent* event) { if (m_currentCaptureState == beginCaptureImage) { m_endPoint = event->pos(); update(); } else if (m_currentCaptureState == beginMoveCaptureArea) { m_endMovePoint = event->pos(); update(); } // 根据鼠标是否在选中区域内设置鼠标样式; if (isPressPointInSelectRect(event->pos())) { setCursor(Qt::SizeAllCursor); } else if (!isPressPointInSelectRect(event->pos()) && m_currentCaptureState != beginMoveCaptureArea) { setCursor(Qt::ArrowCursor); } return QWidget::mouseMoveEvent(event); } void CaptureScreen::mouseReleaseEvent(QMouseEvent *event) { if (m_currentCaptureState == beginCaptureImage) { m_currentCaptureState = finishCaptureImage; m_endPoint = event->pos(); update(); } else if (m_currentCaptureState == beginMoveCaptureArea) { m_currentCaptureState = finishMoveCaptureArea; m_endMovePoint = event->pos(); update(); } return QWidget::mouseReleaseEvent(event); } // 当前鼠标坐标是否在选取的矩形区域内; bool CaptureScreen::isPressPointInSelectRect(QPoint mousePressPoint) { QRect selectRect = getRect(m_beginPoint, m_endPoint); if (selectRect.contains(mousePressPoint)) { return true; } return false; } void CaptureScreen::paintEvent(QPaintEvent *event) { m_painter.begin(this); //进行重绘; QColor shadowColor = QColor(0, 0, 0, 100); //阴影颜色设置; m_painter.setPen(QPen(Qt::blue, 1, Qt::SolidLine, Qt::FlatCap)); //设置画笔; m_painter.drawPixmap(0, 0, m_loadPixmap); //将背景图片画到窗体上; m_painter.fillRect(m_loadPixmap.rect(), shadowColor); //画影罩效果; switch (m_currentCaptureState) { case initCapture: break; case beginCaptureImage: case finishCaptureImage: case beginMoveCaptureArea: case finishMoveCaptureArea: m_currentSelectRect = getSelectRect(); drawCaptureImage(); default: break; } m_painter.end(); //重绘结束; } // 根据当前截取状态获取当前选中的截图区域; QRect CaptureScreen::getSelectRect() { if (m_currentCaptureState == beginCaptureImage || m_currentCaptureState == finishCaptureImage) { return getRect(m_beginPoint, m_endPoint); } else if (m_currentCaptureState == beginMoveCaptureArea || m_currentCaptureState == finishMoveCaptureArea) { return getMoveRect(); } return QRect(0, 0, 0, 0); } // 绘制当前选中的截图区域; void CaptureScreen::drawCaptureImage() { m_capturePixmap = m_loadPixmap.copy(m_currentSelectRect); m_painter.drawPixmap(m_currentSelectRect.topLeft(), m_capturePixmap); m_painter.drawRect(m_currentSelectRect); } void CaptureScreen::keyPressEvent(QKeyEvent *event) { // Esc 键退出截图; if (event->key() == Qt::Key_Escape) { close(); } // Eeter键完成截图; if (event->key() == Qt::Key_Return || event->key() == Qt::Key_Enter) { signalCompleteCature(m_capturePixmap); close(); } } // 根据beginPoint , endPoint 获取当前选中的矩形 QRect CaptureScreen::getRect(const QPoint &beginPoint, const QPoint &endPoint) { int x, y, width, height; width = qAbs(beginPoint.x() - endPoint.x()); height = qAbs(beginPoint.y() - endPoint.y()); x = beginPoint.x() < endPoint.x() ? beginPoint.x() : endPoint.x(); y = beginPoint.y() < endPoint.y() ? beginPoint.y() : endPoint.y(); QRect selectedRect = QRect(x, y, width, height); // 避免宽或高为零时拷贝截图有误; // 可以看QQ截图，当选取截图宽或高为零时默认为2; if (selectedRect.width() == 0) { selectedRect.setWidth(1); } if (selectedRect.height() == 0) { selectedRect.setHeight(1); } return selectedRect; } // 获取移动后,当前选中的矩形; QRect CaptureScreen::getMoveRect() { // 通过getMovePoint方法先检查当前是否移动超出屏幕; QPoint movePoint = getMovePoint(); QPoint beginPoint = m_beginPoint + movePoint; QPoint endPoint = m_endPoint + movePoint; // 结束移动选区时更新当前m_beginPoint , m_endPoint,防止下一次操作时截取的图片有问题; if (m_currentCaptureState == finishMoveCaptureArea) { m_beginPoint = beginPoint; m_endPoint = endPoint; m_beginMovePoint = QPoint(0, 0); m_endMovePoint = QPoint(0, 0); } return getRect(beginPoint, endPoint); } QPoint CaptureScreen::getMovePoint() { QPoint movePoint = m_endMovePoint - m_beginMovePoint; QRect currentRect = getRect(m_beginPoint, m_endPoint); // 检查当前是否移动超出屏幕; //移动选区是否超出屏幕左边界; if (currentRect.topLeft().x() + movePoint.x() < 0) { movePoint.setX(0 - currentRect.topLeft().x()); } //移动选区是否超出屏幕上边界; if (currentRect.topLeft().y() + movePoint.y() < 0) { movePoint.setY(0 - currentRect.topLeft().y()); } //移动选区是否超出屏幕右边界; if (currentRect.bottomRight().x() + movePoint.x() > m_screenwidth) { movePoint.setX(m_screenwidth - currentRect.bottomRight().x()); } //移动选区是否超出屏幕下边界; if (currentRect.bottomRight().y() + movePoint.y() > m_screenheight) { movePoint.setY(m_screenheight - currentRect.bottomRight().y()); } return movePoint; }