Qt5.14 绘画板 Qt Creator C++项目

#include "mainwindow.h" #include "ui_mainwindow.h" #include <QTime> #include <QGraphicsRectItem> #include <QInputDialog> #include <QColorDialog> #include <QFontDialog> #include <QKeyEvent> #include <QDesktopServices> void MainWindow::setItemProperty(QGraphicsItem *item,QString desciption) { item->setFlags(QGraphicsItem::ItemIsMovable //可移动 | QGraphicsItem::ItemIsSelectable //可选中 | QGraphicsItem::ItemIsFocusable); //可以获得焦点 item->setZValue(++frontZ); //叠放顺序号 quint32 v1=QRandomGenerator::global()->bounded(boundValue); quint32 v2=QRandomGenerator::global()->bounded(boundValue); item->setPos(v1,v2); //在场景中的位置 item->setData(ItemId,++seqNum); //图形项编号 item->setData(ItemDesciption,desciption); //图形项描述 scene->addItem(item); //添加到场景 scene->clearSelection(); item->setSelected(true); } MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); scene=new QGraphicsScene(-300,-200,600,400); //创建QGraphicsScene ui->gView->setScene(scene); //scene与view关联 ui->gView->setCursor(Qt::CrossCursor); //设置鼠标光标 ui->gView->setMouseTracking(true); //设置鼠标跟踪 ui->gView->setDragMode(QGraphicsView::RubberBandDrag); //设置拖动模式 this->setCentralWidget(ui->gView); } MainWindow::~MainWindow() { delete ui; } //鼠标移动，point是视图的坐标,物理坐标 void MainWindow::do_mouseMovePoint(QPoint point) { labViewCord->setText(QString::asprintf( "View 坐标：%d,%d", point.x(),point.y())); QPointF pointScene=ui->gView->mapToScene(point); //转换到Scene坐标 labSceneCord->setText(QString::asprintf( "Scene 坐标：%.0f,%.0f", pointScene.x(),pointScene.y())); } //鼠标单击事件 void MainWindow::do_mouseClicked(QPoint point) { QPointF pointScene=ui->gView->mapToScene(point); //转换到Scene坐标 QGraphicsItem *item=NULL; item=scene->itemAt(pointScene,ui->gView->transform()); //获取光标下的图形项 if (item != NULL) //有图形项 { QPointF pointItem=item->mapFromScene(pointScene); //转换为图形项的局部坐标 labItemCord->setText(QString::asprintf( "Item 坐标：%.0f,%.0f",pointItem.x(),pointItem.y())); labItemInfo->setText(item->data(ItemDesciption).toString()+", ItemId="+ item->data(ItemId).toString()); } } //按键事件 void MainWindow::do_keyPress(QKeyEvent *event) { if (scene->selectedItems().count()!=1) return; //没有选中的图形项，或选中的多于1个 QGraphicsItem *item=scene->selectedItems().at(0); if (event->key()==Qt::Key_Delete) //删除 scene->removeItem(item); else if (event->key()==Qt::Key_Space) //顺时针旋转90度 item->setRotation(90+item->rotation()); else if (event->key()==Qt::Key_PageUp) //放大 item->setScale(0.1+item->scale()); else if (event->key()==Qt::Key_PageDown)//缩小 item->setScale(-0.1+item->scale()); else if (event->key()==Qt::Key_Left) //左移 item->setX(-1+item->x()); else if (event->key()==Qt::Key_Right) //右移 item->setX(1+item->x()); else if (event->key()==Qt::Key_Up) //上移 item->setY(-1+item->y()); else if (event->key()==Qt::Key_Down) //下移 item->setY(1+item->y()); } //添加一个矩形 void MainWindow::on_actItem_Rect_triggered() { QGraphicsRectItem *item=new QGraphicsRectItem(-50,-25,100,50);//创建一个矩形图元，并设置局部坐标为（-50,-25）,长100宽50 // 颜色选择 QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setBrush(QBrush(color)); } setItemProperty(item, "矩形");//设置图元属性为“矩形” } //添加一个正方形 void MainWindow::on_actItem_Square_triggered() { QGraphicsRectItem *item=new QGraphicsRectItem(-50,-35,80,80);//设置局部坐标为(-50,-30) QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setBrush(QBrush(color)); } setItemProperty(item, "正方形"); } //添加一个椭圆 void MainWindow::on_actItem_Ellipse_triggered() { QGraphicsEllipseItem *item=new QGraphicsEllipseItem(-50,-30,100,60);//设置局部坐标为(-50,-30) QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setBrush(QBrush(color)); } setItemProperty(item, "椭圆"); } //添加一条直线 void MainWindow::on_actItem_Line_triggered() { QGraphicsLineItem *item=new QGraphicsLineItem(-100,0,100,0);//起始点坐标为（-100，0） QPen pen(Qt::red);//设置画笔为红色 pen.setWidth(3);//宽度为3个像素 QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setPen(QPen(color)); } setItemProperty(item,"直线"); } //添加一个梯形 void MainWindow::on_actItem_Polygon_triggered() { QGraphicsPolygonItem *item=new QGraphicsPolygonItem; QPolygonF points; //创建多边形的顶点坐标列表 //添加顶点坐标 points.append(QPointF(-40,-40)); points.append(QPointF(40,-40)); points.append(QPointF(100,40)); points.append(QPointF(-100,40)); item->setPolygon(points); //设置图元的多边形形状 QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setBrush(QBrush(color)); } setItemProperty(item,"梯形"); } //添加一个圆形 void MainWindow::on_actItem_Circle_triggered() { QGraphicsEllipseItem *item=new QGraphicsEllipseItem(-50,-50,100,100); QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setBrush(QBrush(color)); } setItemProperty(item,"圆形"); } //添加一个三角形 void MainWindow::on_actItem_Triangle_triggered() { QGraphicsPolygonItem *item=new QGraphicsPolygonItem; QPolygonF points; //创建多边形的顶点坐标列表 //添加顶点坐标 points.append(QPointF(0,-40)); points.append(QPointF(60,40)); points.append(QPointF(-60,40)); item->setPolygon(points); //设置图元的多边形形状 QColorDialog colorDialog; if (colorDialog.exec()) { QColor color = colorDialog.selectedColor(); item->setBrush(QBrush(color)); } setItemProperty(item,"三角形"); } //添加文字 void MainWindow::on_actItem_Text_triggered() { QString str=QInputDialog::getText(this,"输入文字","请输入文字"); if (str.isEmpty()) return; //创建一个文字图元，并设置显示的文本为用户输入的文字 QGraphicsTextItem *item=new QGraphicsTextItem(str); QFont font=this->font(); font.setPointSize(20); font.setBold(true); item->setFont(font); //设置字体样式 setItemProperty(item,"文字"); } //删除所有选中的图形项 void MainWindow::on_actEdit_Delete_triggered() { int cnt=scene->selectedItems().count();//获取选中的图形项的个数 for (int i=0;i<cnt;i++) {//遍历选中的图形项 QGraphicsItem* item=scene->selectedItems().at(0);//获取选中的第一个图形项 scene->removeItem(item); //从场景中移除该图形项 delete item;