#include "widget.h" #include "ui_widget.h" #include "qpainter.h" #include "qevent.h" #include "qdebug.h" Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) { ui->setupUi(this); this->setMouseTracking(true); } Widget::~Widget() { delete ui; } void Widget::mouseMoveEvent(QMouseEvent *event) { lastPos = event->pos(); update(); } void Widget::mouseReleaseEvent(QMouseEvent *event) { //这里是鼠标按下的坐标,自己存到数据库 lastPos = event->pos(); update(); qDebug() << lastPos; } void Widget::paintEvent(QPaintEvent *) { QPainter painter(this); QPen pen; pen.setWidth(5); pen.setColor(Qt::red); painter.setPen(pen); //绘制横向线 painter.drawLine(0, lastPos.y(), width(), lastPos.y()); //绘制纵向线 painter.drawLine(lastPos.x(), 0, lastPos.x(), height()); }