QRadar/cradar.cpp at master · spygg/QRadar · GitHub

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#include "cradar.h"
#include <QPainter>
#include <QTimerEvent>
#include <QConicalGradient>
#include <qDebug>

CRadar::CRadar(QWidget *parent) : QWidget(parent)
{
    //初始化
    m_pieRotate = 0;
    m_timerId = -1;
    m_nSpeed = 50;
    m_points<<QPoint()<<QPoint()<<QPoint()<<QPoint()<<QPoint();
    m_pointsAlapha<<100<<100<<100<<100<<100;

    //启动定时器
    m_timerId = startTimer(m_nSpeed);
    m_pointTimerId = startTimer(1200);
}

void CRadar::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);

    //抗锯齿
    painter.setRenderHint(QPainter::Antialiasing);

    //背景
    painter.fillRect(rect(),QColor(15,45,188));

    //边长
    int len = m_drawArea.width();

    //底盘(x轴、y轴和3个圆)
    painter.setPen(QPen(Qt::white));
    painter.drawLine(m_drawArea.topLeft() + QPoint(0,len/2),m_drawArea.topRight() + QPoint(0,len/2));
    painter.drawLine(m_drawArea.topLeft() + QPoint(len/2,0),m_drawArea.bottomLeft() + QPoint(len/2,0));
    painter.drawEllipse(m_drawArea.center(),len/2,len/2);
    painter.drawEllipse(m_drawArea.center(),len/3,len/3);
    painter.drawEllipse(m_drawArea.center(),len/6,len/6);

    //转动部分
        //---//线
    qreal x = m_drawArea.center().x() + (qreal)len/2 * cos(-m_pieRotate*3.14159/180);
    qreal y = m_drawArea.center().y() + (qreal)len/2 * sin(-m_pieRotate*3.14159/180);
    painter.setPen(QPen(Qt::white));
    painter.drawLine(m_drawArea.center(),QPointF(x,y));

       //----//扇形
    QConicalGradient gradient;
    gradient.setCenter(m_drawArea.center());
    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(255,255,255,100)); //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(255,255,255,0));
    painter.setBrush(QBrush(gradient));
    painter.setPen(Qt::NoPen);
    painter.drawPie(m_drawArea,m_pieRotate*16,90*16);

    //装饰-随机点
    for(int i = 0; i < m_points.count(); ++i)
    {
        int colorAlaph = m_pointsAlapha.at(i);
        painter.setPen(QPen(QColor(255,255,255,colorAlaph),3));
        painter.drawPoint(m_points.at(i));
    }

    //更详细解释参考：http://fearlazy.com/index.php/post/31.html
}

void CRadar::resizeEvent(QResizeEvent *event)
{
    //以较短的边长作为绘制区域边长
    if(width() > height())
    {
        m_drawArea = QRect((width() - height())/2,0,height(),height());
    }
    else
    {
        m_drawArea = QRect(0,(height() - width())/2,width(),width());
    }

    m_drawArea.adjust(10,10,-10,-10);
}

void CRadar::timerEvent(QTimerEvent *event)
{
    if(m_timerId == event->timerId())
    {
        m_pieRotate -= 10;
        update();
    }
    else if(m_pointTimerId == event->timerId())
    {
        //随机更换装饰的点
        for(int i = 0; i < m_points.count(); ++i)
        {
            int offsetX = rand()%m_drawArea.width();
            int offsetY = rand()%m_drawArea.width();
            int alapha = rand()%255;
            m_points.replace(i,QPoint(offsetX,offsetY) + m_drawArea.topLeft());
            m_pointsAlapha.replace(i,alapha);
        }

        update();
    }
}