QT的实时跟随鼠标绘制彩色线条详细代码

#include "mainwindow.h" #include <QPaintEvent> #include <QPainter> #include <QPainterPath> #include <QLinearGradient> #include <QVector2D> #include <QTimer> #include <gl/GLU.h> #include <QGraphicsPixmapItem> #include <QPushButton> MainWindow::MainWindow(QWidget *parent) : QOpenGLWidget(parent) { resize(1080, 720); QPushButton* btn=new QPushButton(this); btn->setText("清空/启动"); btn->setGeometry(100,100,100,100); connect(btn,&QPushButton::clicked,this,[&]() { if(calculator->state) { //退出线程清空绘图 calculator->killThread(); thread->exit(0); thread->wait(); path.clear(); pixmap =QPixmap(size()); pixmap.fill(Qt::transparent); update(); } else { //重启线程 calculator->state=true; thread->start(); calculator->annotationPath.clear(); calculator->pixmap = QPixmap(1080,720); calculator->list.clear(); calculator->pixmap.fill (Qt :: transparent); path.clear(); } }); this->setWindowFlags(Qt::WindowStaysOnTopHint); this->setAttribute(Qt::WA_TranslucentBackground); this->setAttribute(Qt::WA_TransparentForMouseEvents); thread = new QThread(); // 创建计算对象 calculator = new MyCalculator(); // 将计算对象移动到子线程中 calculator->moveToThread(thread); // 连接信号和槽 connect(thread, &QThread::started, calculator, &MyCalculator::calculate); connect(calculator, &MyCalculator::finished, this, &MainWindow::onCalculateFinish,Qt::QueuedConnection); // 启动子线程 thread->start(); QTimer* m_pTimer = new QTimer(this); connect(m_pTimer, SIGNAL(timeout()), this, SLOT(handleTimeout())); m_pTimer->start(30); //50ms定时刷新一次界面 pen.setColor(Qt::transparent); pen.setWidth(8); img = QImage(size(), QImage::Format_RGB32); img.fill(qRgb(255, 255, 255)); pixmap =QPixmap(size()); pixmap.fill(Qt::transparent); } void MainWindow::handleTimeout() { update(); } void MainWindow::onCalculateFinish(QPixmap pix) { qDebug() << "Main Thread ID2:" << QThread::currentThreadId(); pixmap=pix; } void MainWindow::mouseMoveEvent(QMouseEvent *event) { path.lineTo(event->pos()); calculator->setPath(path); } MainWindow::~MainWindow() { qDebug()<<"xigou"; calculator->killThread(); thread->exit(0); thread->wait(); // wait函数是个阻塞的接口，意思是线程必须真的退出了，才会执行wait之后的语句，否则将会一直阻塞在这里，如果在界面线程上使用，需要保证线程中代码的合理性。 thread = nullptr; } void MainWindow::initializeGL() { initializeOpenGLFunctions(); glClearColor(0, 0, 0, 0); } void MainWindow::resizeGL(int width, int height) { glViewport(0, 0, width, height); } void MainWindow::paintGL() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glClearColor(0, 0, 0, 0); QPainter painter(this); painter.setRenderHint(QPainter::SmoothPixmapTransform, true); painter.drawPixmap(0,0,pixmap); }