Qt利用QPainter自绘实现扫描雷达功能scanneritem

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忘记了，艹，对不起原作者了。

.pro

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += 
    main.cpp 
    mainwindow.cpp 
    scanneritem.cpp

HEADERS += 
    mainwindow.h 
    scanneritem.h

FORMS += 
    mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "scanneritem.h"

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    Widget *oWidget = new Widget(this);

    oWidget->setGeometry(10, 10, this->width(), this->height());
}

MainWindow::~MainWindow()
{
    delete ui;
}

scanneritem.h

#ifndef SCANNERITEM_H
#define SCANNERITEM_H

#include "QWidget"
#include "QList"
#include "QTimer"
#include "QPainter"
#include "QPixmap"
#include "QTime"
#include "QDebug"

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    QPixmap paintWidget();

protected:
    void paintEvent(QPaintEvent *event);
    void resizeEvent(QResizeEvent *event);
protected slots:
    void timerTimeOut();

private:
    QTimer *timer;
    QPoint point;
    int i_diameter=0;
    double d_angle=0;
    QList<QPixmap> list_pixmap;
};

#endif // SCANNERITEM_H

scanneritem.cpp

#include "scanneritem.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent)
{
    this->setStyleSheet("background-color:black");//设置窗口背景色为黑色
    timer = new QTimer();
    connect(timer,SIGNAL(timeout()),this,SLOT(timerTimeOut()));

    timer->start(10);
}

Widget::~Widget()
{

}

void Widget::resizeEvent(QResizeEvent *event)
{
    if(this->width() > this->height()){
        point = QPoint((this->width()-this->height())/2+(this->height()-12)/2,this->height()/2);
        i_diameter = this->height()-12;
    }else{
        point = QPoint(this->width()/2,(this->height()-this->width())/2+(this->width()-12)/2);
        i_diameter = this->width()-12;
    }
}

QPixmap Widget::paintWidget()
{
    QPixmap pixmap(this->width(),this->height());
    QPainter p_painter(&pixmap);
    QPen pen;
    QTime timedebug;
    timedebug.start();
    //反锯齿
    p_painter.setRenderHint(QPainter::Antialiasing);
    pixmap.fill(Qt::black);

    pen.setColor(Qt::green);
    p_painter.setPen(pen);

    pen.setColor(Qt::gray);
    p_painter.setPen(pen);
    p_painter.drawLine(point.x(),point.y()-i_diameter/2-10,point.x(),point.y()+i_diameter/2+10);//画坐标
    p_painter.drawLine(point.x()-i_diameter/2-10,point.y(),point.x()+i_diameter/2+10,point.y());
    pen.setColor(Qt::green);
    p_painter.setPen(pen);
    for(int i=0; i<6; i++){
        p_painter.drawEllipse(point.x()-i_diameter*0.2*i/2,point.y()-i_diameter*0.2*i/2,i_diameter*0.2*i,i_diameter*0.2*i);
    }

    QConicalGradient conical_gradient(point,(6.28-d_angle)/6.28*720);//定义圆心和渐变的角度
    conical_gradient.setColorAt(0,Qt::green);
    conical_gradient.setColorAt(0.2,QColor(255,255,255,0));
    p_painter.setBrush(conical_gradient);
    p_painter.drawEllipse(point.x()-i_diameter/2,point.y()-i_diameter/2,i_diameter,i_diameter);


    qDebug()<<"time_end="<<timedebug.elapsed()<<"ms";

    return pixmap;

}

void Widget::timerTimeOut()
{
    timer->start(10);
    d_angle += 3.14/720;
    if(d_angle >= 6.28){
        d_angle = 0;
    }
    update();

}

void Widget::paintEvent(QPaintEvent *event)
{
    QPainter p_painter(this);
    //反锯齿
    p_painter.setRenderHint(QPainter::Antialiasing, true);

    p_painter.drawPixmap(0,0,this->width(),this->height(),paintWidget());

    QWidget::paintEvent(event);
}