QT学习之三维饼图绘制

怼烎@ 2022-08-17 14:21 223阅读 0赞

QT里没有相应统计图形的绘制组件  
只有手工自己画

效果如图

![1363186157_5382.png][]

void aaq::paintEvent( QPaintEvent* ev )
    {
        QPainter painter(this);
        // 去除画笔
        painter.setPen(Qt::NoPen);
        // 设置反锯齿
        painter.setRenderHint(QPainter::Antialiasing);
    
        //******************************************** 圆饼图 *****************************************//
        if(1)
        {
            // 顶层圆面
            QRectF rect_top(10.0, 20.0, 280.0, 160.0);
            // 底层圆面
            QRectF rect_bottom(10.0, 60.0, 280.0, 160.0);
            // 中间矩形
            QRectF rect_midd(10.0, 100.0, 280.0, 40.0);
    
            // 扇形起始角度
            int startAngle = 230 * 16;
            // 扇形覆盖范围
            int spanAngle = 60 * 16;
    
            painter.setBrush(QColor(97,35,35,255));
            // 绘制底层圆面
            painter.drawEllipse(rect_bottom);
            // 绘制中间矩形
            painter.drawRect(rect_midd);
    
            painter.setBrush(QColor(Qt::darkYellow));
            // 绘制底层扇形
            painter.drawPie(rect_bottom, startAngle, spanAngle);
    
            // 扇形的弦与弧的交点
            double pi = 3.1415926;
            double dx1 = rect_top.width() * 0.5 * cos(230 * pi / 180);
            double dy1 = rect_top.height() * 0.5 * sin(230 * pi / 180);
    
            double dx2 = rect_top.width() * 0.5 * cos(290 * pi / 180);
            double dy2 = rect_top.height() * 0.5 * sin(290 * pi / 180);
    
    
            // 求交点的坐标值
            QPointF posBackCenter = QPointF(rect_top.center());
            double dX1 = posBackCenter.x() + dx1 + 0.5;
            double dY1 = posBackCenter.y() - dy1 + 0.5;
    
            double dX2 = posBackCenter.x() + dx2 + 0.5;
            double dY2 = posBackCenter.y() - dy2 + 0.5;
    
            // 记录交点
            QPointF topLeft = QPointF(dX1, dY1);
            QPointF bottomRight = QPointF(dX2, dY2) + QPointF(0,40);
            QPointF bottomLeft = topLeft + QPointF(0,40);
            painter.setBrush(QColor(Qt::darkYellow));
    
            // 绘制连接扇形的区域
            QPolygonF path;
            path << topLeft << QPointF(dX2,dY2) << bottomRight << bottomLeft;
            painter.drawPolygon(path);
    
            // 绘制顶层圆面
            painter.setBrush(QColor(156,56,56,255));
            painter.drawEllipse(rect_top);
    
            // 绘制顶层扇形
            painter.setBrush(QColor(Qt::yellow));
            painter.drawPie(rect_top, startAngle, spanAngle);
        }
    
        QWidget::paintEvent(ev);
    }

[1363186157_5382.png]: https://img-my.csdn.net/uploads/201303/13/1363186157_5382.png