qt、qwt使用实例：三点组圆

#include "mainwindow.h" #include <QMenuBar> #include <QGraphicsItem> #include <QHBoxLayout> #include <QPushButton> #include <QLabel> #include <QLineEdit> #include <QGridLayout> #include <qwt_plot_curve.h> #include <stdio.h> #include "paintview.h" #include "utility.h" MainWindow::MainWindow() { // 初始化变量 init(); // 创建菜单栏 createMenus(); // 设置布局 setMainLayout(); setWindowTitle("School Work"); } /** 初始化成员变量 **/ void MainWindow::init() { _paintView = new PaintView(); _clearAct = new QAction("&Clear",this); _exitAct = new QAction("&Exit",this); _button = new QPushButton("Let's do it"); _button->setMinimumHeight(40); _button->setMaximumWidth(200); // 信号\槽连接 connect(_clearAct,SIGNAL(triggered()),this,SLOT(slotClear())); connect(_exitAct,SIGNAL(triggered()),this,SLOT(close())); connect(_button,SIGNAL(clicked()),this,SLOT(slotDraw())); } /** 创建菜单栏 **/ void MainWindow::createMenus() { QMenu *fileMenu = menuBar()->addMenu("File"); fileMenu->addAction(_clearAct); fileMenu->addAction(_exitAct); } /** 设置布局 **/ void MainWindow::setMainLayout() { // 设置左上侧布局 // 创建6个输入框 for(int i=0;i<6;i++) _arrCoord[i] = new QLineEdit(); // 创建3个标签 QLabel *point1 = new QLabel("point A : "); QLabel *point2 = new QLabel("point B : "); QLabel *point3 = new QLabel("point C : "); // 插入布局 QGridLayout *coordLayout = new QGridLayout(); coordLayout->addWidget(point1,0,0); coordLayout->addWidget(_arrCoord[0],1,0); coordLayout->addWidget(_arrCoord[1],1,1); coordLayout->addWidget(point2,2,0); coordLayout->addWidget(_arrCoord[2],3,0); coordLayout->addWidget(_arrCoord[3],3,1); coordLayout->addWidget(point3,4,0); coordLayout->addWidget(_arrCoord[4],5,0); coordLayout->addWidget(_arrCoord[5],5,1); // 用QFrame使3个标签和6个输入框作为一个整体 QFrame *frame1 = new QFrame(); frame1->setLayout(coordLayout); frame1->setMinimumWidth(150); frame1->setMaximumWidth(200); // 设置左下侧布局 // 创建3个标签 _triangleStats = new QLabel("Triangle : \n\tA ()\n\tB ()\n\tC ()"); _incircleStats = new QLabel("\nIncirclee : \n\tcenter ()\n\tradius = "); _circumcircleStats = new QLabel("\nCircumcirc : \n\tcenter ()\n\tradius = "); // 插入布局 QVBoxLayout *statsLayout = new QVBoxLayout(); statsLayout->setContentsMargins(10,10,10,10); statsLayout->addWidget(_triangleStats); statsLayout->addWidget(_incircleStats); statsLayout->addWidget(_circumcircleStats); // 用QFrame是标签作为整体，QFrame是一个容器，可以设置自己的显示外观 QFrame *frame2 = new QFrame(); frame2->setFrameShape(QFrame::StyledPanel); frame2->setFrameShadow(QFrame::Raised); frame2->setLayout(statsLayout); // 通过QVBoxLayout使其布局紧凑（因为它的addStretch方法） QVBoxLayout *leftLayout = new QVBoxLayout; leftLayout->addWidget(frame1); leftLayout->setSpacing(20); leftLayout->addWidget(_button); leftLayout->addWidget(frame2); leftLayout->addStretch(); QHBoxLayout *mainLayout = new QHBoxLayout(); mainLayout->setSpacing(20); mainLayout->addLayout(leftLayout); mainLayout->addWidget(_paintView); QWidget *widget = new QWidget(); widget->setLayout(mainLayout); setCentralWidget(widget); } /** 槽：清空函数 **/ void MainWindow::slotClear() { // 清除所有item _paintView->detachItems(QwtPlotItem::Rtti_PlotItem); // 再画上x=0和y=0辅助线 _paintView->drawXYLines(); _paintView->replot(); // 清空编辑框 for(int i=0;i<6;i++) _arrCoord[i]->setText(""); // 更新状态区信息 _triangleStats->setText("Triangle : \n\tA ()\n\tB ()\n\tC ()"); _incircleStats->setText("\nIncirclee : \n\tcenter ()\n\tradius = "); _circumcircleStats->setText("\nCircumcirc : \n\tcenter ()\n\tradius = "); } /** 槽：获取用户输入的三个点坐标并绘图 **/ void MainWindow::slotDraw() { // 先清空视图 _paintView->detachItems(QwtPlotItem::Rtti_PlotItem); // 再画上x=0和y=0辅助线 _paintView->drawXYLines(); _paintView->replot(); double x1 = _arrCoord[0]->text().toDouble(); double y1 = _arrCoord[1]->text().toDouble(); double x2 = _arrCoord[2]->text().toDouble(); double y2 = _arrCoord[3]->text().toDouble(); double x3 = _arrCoord[4]->text().toDouble(); double y3 = _arrCoord[5]->text().toDouble(); // 画三角形的三个顶点 QPointF p1(x1, y1); QPointF p2(x2,y2); QPointF p3(x3,y3); _paintView->drawPointsOfTriangle(p1, p2, p3); // 画三角形的三条边 double xval[] = {x1,x2,x3,x1}; double yval[] = {y1,y2,y3,y1}; _paintView->drawEdgesOfTriangle(xval, yval); // 更新状态区三角形信息 QString info = "Triangle : "; info.append("\n A ( " + QString::number(x1) + " , " + QString::number(y1) + " )"); info.append("\n B ( " + QString::number(x2) + " , " + QString::number(y2) + " )"); info.append("\n C ( " + QString::number(x3) + " , " + QString::number(y3) + " )"); _triangleStats->setText(info); // 三点共线 if((y3-y1)/(x3-x1)==(y2-y1)/(x2-x1)) { // 更新状态区内切圆和外接圆信息 info = "\nIncircle : \n\tno incircle"; _incircleStats->setText(info); info = "\ncircumcircle : \n\tno circumcircle"; _circumcircleStats->setText(info); return; } // 画内切圆 QPointF incircleCenter = Utility::caculateIncircleCenter(x1,y1,x2,y2,x3,y3); double incircleRadius = Utility::caculateIncircleRadius(x1,y1,x2,y2,x3,y3); _paintView->drawInscribedCircle(incircleCenter,incircleRadius); // 画外接圆 QPointF circumcircleCenter = Utility::caculateCircumcircleCenter(x1,y1,x2,y2,x3,y3); double circumcircleRadius = Utility::caculateCircumcircleRadius(x1,y1,x2,y2,x3,y3); _paintView->drawCircumscribedCircle(circumcircleCenter,circumcircleRadius); _paintView->replot(); // 更新状态区域的内切圆和外接圆信息 info = "\nIncircle : "; info.append("\n center ( " + QString::number(incircleCenter.x()) + " , " + QString::number(incircleCenter.y()) + " )"); info.append("\n radius = " + QString::number(incircleRadius)); _incircleStats->setText(info); info = "\ncircumcircle : "; info.append("\n center ( " + QString::number(circumcircleCenter.x()) + " , " + QString::number(circumcircleCenter.y()) + " )"); info.append("\n radius = " + QString::number(circumcircleRadius)); _circumcircleStats->setText(info); }