qt 5 使用graphicsview绘制图形的基本操作

#include "mainwindow.h" #include "ui_mainwindow.h" #include <QTime> #include <QGraphicsView> #include <QGraphicsItem> #include <QColor> #include <QColorDialog> #include <QFontDialog> #include <QKeyEvent> #include <QFileDialog> #include <QtMath> #include <QTextDocument> #include <QTimer> MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) , ui(new Ui::MainWindow) { ui->setupUi(this); this->setWindowTitle("Graphics view绘图"); this->setToolButtonStyle(Qt::ToolButtonTextUnderIcon); labViewCord=new QLabel("View 坐标："); labViewCord->setMinimumWidth(150); ui->statusbar->addWidget(labViewCord); labSceneCord=new QLabel("Scene坐标:"); labSceneCord->setMinimumWidth(150); ui->statusbar->addWidget(labSceneCord); labItemCord=new QLabel("Item 坐标："); labItemCord->setMinimumWidth(150); ui->statusbar->addWidget(labItemCord); labItemInfo=new QLabel("Item info:"); labItemInfo->setMinimumWidth(200); ui->statusbar->addWidget(labItemInfo); ui->graphicsView->setCursor(Qt::CrossCursor); ui->graphicsView->setMouseTracking(true); ui->graphicsView->setDragMode(QGraphicsView::RubberBandDrag); this->setCentralWidget(ui->graphicsView); QObject::connect(ui->graphicsView,SIGNAL(mouseMovePoint(QPoint)),this,SLOT(on_mouseMovePoint(QPoint))); QObject::connect(ui->graphicsView,SIGNAL(mouseClicked(QPoint)),this,SLOT(on_mouseClicked(QPoint))); QObject::connect(ui->graphicsView,SIGNAL(mouseDoubleClick(QPoint)),this,SLOT(on_mouseDoubleClick(QPoint))); QObject::connect(ui->graphicsView,SIGNAL(keyPress(QKeyEvent*)),this,SLOT(on_keyPress(QKeyEvent*))); QObject::connect(ui->graphicsView,SIGNAL(mouseReleasePoint(QPoint)),this,SLOT(on_mouseReleasePoint(QPoint))); QObject::connect(ui->graphicsView,SIGNAL(exitEditMode()),this,SLOT(on_exitEditMode())); // QObject::connect(ui->graphicsView,SIGNAL(mousePress(QMouseEvent*)),this,SLOT(on_mousePressEvent(QMouseEvent*))); // QObject::connect(ui->graphicsView,SIGNAL(mouseMove(QMouseEvent*)),this,SLOT(on_mouseMoveEvent(QMouseEvent*))); // QObject::connect(ui->graphicsView,SIGNAL(mouseRelease(QMouseEvent*)),this,SLOT(on_mouseReleaseEvent(QMouseEvent*))); m_timer=new QTimer(this); QObject::connect(m_timer,&QTimer::timeout,this,&MainWindow::timerOut); m_timer->start(50); qsrand(QTime::currentTime().second()); //自定义鼠标形状 // QPixmap *pix=new QPixmap(":/images/pen.ico"); penCursor=QCursor(); penCursor.pixmap().load(":/images/pen.ico"); ui->graphicsView->setCursor(Qt::ArrowCursor); //setFixedSize(1024,768); //this->setWindowFlags(Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint); //this->showMaximized(); } MainWindow::~MainWindow() { delete ui; } void MainWindow::timerOut() { m_timer->stop(); scene=new QGraphicsScene(0,0,ui->graphicsView->width(),ui->graphicsView->height());//-300,-200,600,200); ui->graphicsView->setScene(scene); ui->graphicsView->setAlignment(Qt::AlignLeft|Qt::AlignTop); } void MainWindow::on_mouseMovePoint(QPoint point) { labViewCord->setText(QString::asprintf("View 坐标：%d,%d",point.x(),point.y())); QPointF pointScene=ui->graphicsView->mapToScene(point); labSceneCord->setText(QString::asprintf("Scene坐标：%.0f,%.0f",pointScene.x(),pointScene.y())); viewMove=true; } void MainWindow::on_mouseClicked(QPoint point) { viewMove=false; QPointF pointScene=ui->graphicsView->mapToScene(point); startPoint=pointScene; poly<<startPoint; QGraphicsItem *item=NULL; item=scene->itemAt(point,ui->graphicsView->transform()); if(item!=NULL){ QPointF pointItem=item->mapFromScene(pointScene); labItemCord->setText(QString::asprintf("Item坐标：%.0f,%.0f",pointItem.x(),pointItem.y())); labItemInfo->setText(item->data(itemDescription).toString()+",ItemId= "+item->data(itemId).toString()); } } void MainWindow::on_mouseDoubleClick(QPoint point) { QPointF pointScene=ui->graphicsView->mapToScene(point); QGraphicsItem *item=NULL; item=scene->itemAt(point,ui->graphicsView->transform()); if(item==NULL){ return; } switch (item->type()) { case QGraphicsRectItem::Type: { QGraphicsRectItem *theItem; theItem=qgraphicsitem_cast<QGraphicsRectItem*>(item); setBrushColor(theItem); break; } case QGraphicsEllipseItem::Type: { QGraphicsEllipseItem *theItem; theItem=qgraphicsitem_cast<QGraphicsEllipseItem*>(item); setBrushColor(theItem); break; } case QGraphicsPolygonItem::Type: //多边形 { QGraphicsPolygonItem *theItem; theItem=qgraphicsitem_cast<QGraphicsPolygonItem*>(item); setBrushColor(theItem); break; } case QGraphicsLineItem::Type: { QGraphicsLineItem *theItem; theItem=qgraphicsitem_cast<QGraphicsLineItem*>(item); //setBrushColor(theItem); QPen pen=theItem->pen(); QColor color=theItem->pen().color(); color=QColorDialog::getColor(color,this,"请选择颜色"); if(color.isValid()){ pen.setColor(color); theItem->setPen(pen); } break; } case QGraphicsTextItem::Type: { QGraphicsTextItem *theItem; theItem=qgraphicsitem_cast<QGraphicsTextItem*>(item); QFont font=theItem->font(); bool ok=false; font=QFontDialog::getFont(&ok,font,this,"设置字体"); if(ok){ theItem->setFont(font); } break; } case QGraphicsSimpleTextItem::Type: { QGraphicsSimpleTextItem *theItem; theItem=qgraphicsitem_cast<QGraphicsSimpleTextItem*>(item); QFont font=theItem->font(); break; } default: break; } } template<class T> void MainWindow::setBrushColor(T *item) { QColor color=item->brush().color(); color=QColorDialog::getColor(color,NULL,"请选择颜色"); if(color.isValid()){ item->setBrush(QBrush(color)); } } void MainWindow::on_keyPress(QKeyEvent* event) {//快捷键定义 if(scene->selectedItems().count()!=1){ return; //选中的图形数不等于1 } QGraphicsItem *item=scene->selectedItems().at(0); if(event->key()==Qt::Key_Delete){ scene->removeItem(item); }else if(event->key()==Qt::Key_Space){ item->setRotation(90+item->rotation()); }else if(event->key()==Qt::Key_PageUp){ item->setScale(0.1+item->scale()); }else if(event->key()==Qt::Key_PageDown){ item->setScale(-0.1+item->scale()); }else if(event->key()==Qt::Key_Left){ item->setX(-1+item->x()); }else if(event->key()==Qt::Key_Right){ item->setX(1+item->x()); }else if(event->key()==Qt::Key_Up){ item->setY(-1+item->y()); }else if(event->key()==Qt::Key_Down){ item->setY(1+item->y()); } } void MainWindow::on_mouseReleasePoint(QPoint point) { QPointF pointScene=ui->graphicsView->mapToScene(point); endPoint=pointScene; poly<<endPoint; switch (shape) { case noShape: break; case rect: { QGraphicsRectItem *item=new QGraphicsRectItem(startPoint.x(),startPoint.y(),abs(endPoint.x()-startPoint.x()),abs(endPoint.y()-startPoint.y())); item->setFlags(QGraphicsItem::ItemIsMovable|QGraphicsItem::ItemIsSelectable|QGraphicsItem::ItemIsFocusable); QPointF pt=item->mapFromScene(startPoint); item->setPos(0,0); item->setBrush(QBrush(Qt::red)); item->setZValue(++frontZ); item->setData(itemId,++segNum); item->setData(itemDescription,"矩形"); scene->addIte