QT雷达扫描仪表，两种扫描方式。

#include "widget.h" #define PI 3.14159 #define NoalmalSize 10 #define maxSize 30 #define ShowRange 30 #define MaxPoints 200 #define ShowPointsInterval 100 #define AngleInterval 1 Widget::Widget(QWidget *parent) : QWidget(parent) { resize(600,600); this->startTimer(25); initdata(); } Widget::~Widget() { } void Widget::initdata() { m_desPoints.clear(); for (int i = 0; i < qrand()%MaxPoints; ++i) { QPointF p; if (i % 4 == 0) { p.setX(qrand()/(width()/5)); p.setY(qrand()/(height()/5)); } else if (i % 4 == 1) { p.setX(-qrand()/(width()/5)); p.setY(qrand()/(height()/5)); } else if (i % 4 == 2) { p.setX(qrand()/(width()/5)); p.setY(-qrand()/(height()/5)); } else if (i % 4 == 3) { p.setX(-qrand()/(width()/5)); p.setY(-qrand()/(height()/5)); } m_desPoints.append(p); } // m_desPoints<<QPoint(100,0)<<QPoint(0,100)<<QPoint(0,-100)<<QPoint(-100,0)<<QPoint(50*qSqrt(3),-50)<<QPoint(50*qSqrt(2),50*qSqrt(2)); } void Widget::timerEvent(QTimerEvent *event) { static int index = 0; m_pieRotate+=AngleInterval; if (index++ == ShowPointsInterval) { index = 0; initdata(); } update(); } void Widget::paintEvent(QPaintEvent *event) { #if 1 QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing); QString pixpath = QApplication::applicationDirPath()+"/世界地图.jfif"; painter.drawPixmap(0,0,width(),height(),QPixmap(pixpath)); painter.setPen(Qt::white); painter.drawLine(QPoint(width()/2,0),QPoint(width()/2,height())); painter.drawLine(QPoint(0,height()/2),QPoint(width(),height()/2)); painter.translate(width()/2,height()/2); painter.setPen(Qt::white); painter.drawEllipse(QPoint(0,0),width()/2,height()/2); painter.drawEllipse(QPoint(0,0),width()/4,height()/4); painter.drawEllipse(QPoint(0,0),width()/8,height()/8); painter.drawEllipse(QPoint(0,0),width()/16,height()/16); painter.drawEllipse(QPoint(0,0),width()/32,height()/32); //余晖扫描 // int len = m_drawArea.width(); double x = width()/2 * cos(m_pieRotate*PI/180); double y = height()/2 * sin(m_pieRotate*PI/180); painter.setPen(QPen(Qt::green)); painter.drawLine(QPoint( 0, 0 ),QPointF(x,y)); //扇形 QConicalGradient gradient; gradient.setCenter(QPoint( 0, 0 )); gradient.setAngle(-m_pieRotate + 180); //渐变与旋转方向恰好相反，以扇形相反的边作为渐变角度。 gradient.setColorAt(0.4,QColor(169,253,51,100)); //从渐变角度开始0.5 - 0.75为扇形区域，由于Int类型计算不精确，将范围扩大到0.4-0.8 gradient.setColorAt(0.8,QColor(169,253,51,0)); painter.setBrush(QBrush(gradient)); painter.setPen(Qt::NoPen); painter.drawPie(-width()/2,-height()/2,width(),height(),-m_pieRotate*16,90*16); //目标圆位置 QPointF p1(0,0); //扫描线起点坐标 QPointF p2(x,y); //扫描线终点坐标 for (int i = 0; i < m_desPoints.size(); ++i) { QPointF Q = m_desPoints[i]; #if 1 scanRegion1(painter,Q,p1,p2,i); #else scanRegion2(painter,Q,p1,p2,i); #endif } #endif } void Widget::scanRegion1(QPainter &painter,QPointF Q,QPointF p1,QPointF p2,int index) { double s1 = atan2(Q.y(),Q.x())*180/PI; double s2 = atan2(p2.y(),p2.x())*180/PI; painter.save(); painter.translate(Q); painter.rotate(2*m_pieRotate); //按照弧度来计算,此处求弧度的方法atan、atan2、qAtan、qAtan2。 //atan弧度范围[-PI/2,PI/2]、atan2弧度范围[-PI,PI] if (s1 <= s2 && s1 >= s2 - ShowRange) //判断一个范围内出现的目标。（范围扫描） // if (s2 >= qFloor(s1) && s2 <= qCeil(s1)) //判断扫描线上出现的目标。（准点扫描） { painter.setPen(Qt::green); painter.setBrush(QBrush(QColor(255,255,255,50))); QPointF P = QPointF(0,0); //移到坐标原点，配合rotate实现自转。 painter.drawEllipse(P,maxSize,maxSize); painter.drawRect(P.x()-(maxSize+4)/2,P.y()-(maxSize+4)/2,maxSize+4,maxSize+4); painter.drawText(P.x()-(maxSize+4)/2,P.y()-(maxSize+4)/2,maxSize+4,maxSize+4,Qt::AlignCenter,QString::number(index)); } else { painter.setPen(Qt::red); painter.setBrush(QBrush(QColor(255,255,255,50))); QPointF P = QPointF(0,0); //移到坐标原点，配合rotate实现自转。 painter.drawEllipse(P,NoalmalSize,NoalmalSize); painter.drawRect(P.x()-(NoalmalSize+4)/2,P.y()-(NoalmalSize+4)/2,NoalmalSize+4,NoalmalSize+4); } painter.restore(); } void Widget::scanRegion2(QPainter &painter,QPointF Q,QPointF p1,QPointF p2,int index) { painter.save(); painter.translate(Q); painter.rotate(2*m_pieRotate); // 叉积公式：（Q - P1） * （P2 - P1）= 0 判断Q点是否在点P1到P2的线段上 // (Q.x - P1.x) * (P2.y - P1.y) == (P2.x - P1.x) * (Q.y - P1.y) // int val = (Q.x() - p1.x())*(p2.y() - p1.y()) - (p2.x() - p1.x())*(Q.y() - p1.y()); //等比 三角形A（边abc）和三角形B（边efg）是等比三角形，所以a/e = b/f = c/g.扫描线和出现在扫描线上的坐标点构成等比三角形。 double val = (Q.x() - p1.x())/(p2.x() - p1.x()) - (Q.y() - p1.y())/(p2.y() - p1.y()); // qDebug()<<val; if ( val<= 0.1 && val >= -0.1 && qMin(p1.x() , p2.x()) <= Q.x() && Q.x() <= qMax(p1.x() , p2.x()) && qMin(p1.y() , p2.y()) <= Q.y() && Q.y() <= qMax(p1.y() , p2.y())) { painter.setPen(Qt::green); painter.setBrush(QBrush(QColor(255,255,255,50))); QPointF P = QPointF(0,0); //移到坐标原点，配合rotate实现自转。 painter.drawEllipse(P,maxSize,maxSize); painter.drawRect(P.x()-(maxSize+4)/2,P.y()-(maxSize+4)/2,maxSize+4,maxSize+4); painter.drawText(P.x()-(maxSize+4)/2,P.y()-(maxSize+4)/2,maxSize+4,maxSize+4,Qt::AlignCenter,QString::number(index)); } else { painter.setPen(Qt::red); painter.setBrush(QBrush(QColor(255,255,255,50))); QPointF P = QPointF(0,0); //移到坐标原点，配合rotate实现自转。 painter.drawEllipse(P,NoalmalSize,NoalmalSize); painter.drawRect(P.x()-(NoalmalSize+4)/2,P.y()-(NoalmalSize+4)/2,NoalmalSize+4,NoalmalSize+4); } painter.restore(); }