Qt Creator 做的涂鸦板 + 矩形绘图

#include "mainwindow.h" #include "ui_mainwindow.h" #include <QPainter> #include <QMouseEvent> #include <QRectF> bool IsDrawing; QRectF Rectf; MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { bool bl = pic.load(tr("E:\\QT\\Test\\Tuya\\IMG_5627.jpg"),0); map1 = QPixmap(400,400); map1.fill(Qt::white); ui->setupUi(this); } MainWindow::~MainWindow() { delete ui; } void MainWindow:: paintEvent(QPaintEvent *) { QPainter painter(this); painter.drawImage(QPointF(0.0f,0.0f),pic); //map2.fill(Qt::white); if(IsDrawing) { map2 = map1; QPainter temp(&map2); temp.drawRect(Rectf); painter.drawPixmap(0,0,map2); }else { QPainter temp(&map1); temp.drawRect(Rectf); painter.drawPixmap(0,0,map1); } } int flag_L = 0; void MainWindow:: mousePressEvent(QMouseEvent *event) { if(event->button() & Qt::LeftButton) { flag_L = 1; Rectf.setX(event->x()); Rectf.setY(event->y()); IsDrawing = 1; } // pic.setPixel(); } void MainWindow::mouseReleaseEvent(QMouseEvent *event) { if(event->button() & Qt::LeftButton) { flag_L = 0; IsDrawing = 0; Rectf.setWidth(event->x() - Rectf.x()); Rectf.setHeight(event->y() - Rectf.y()); update(); } } void MainWindow:: mouseMoveEvent(QMouseEvent *event) { int p_x = event->x(); int p_y = event->y(); if(flag_L) { pic.setPixel(p_x, p_y,0x00000); IsDrawing = 1; Rectf.setWidth(event->x() - Rectf.x()); Rectf.setHeight(event->y() - Rectf.y()); update(); } }