QT绘制同心扇形

void ChartForm::paintEvent(QPaintEvent *)
{QPainter painter(this);painter.setRenderHint(QPainter::Antialiasing);// 设置抗锯齿painter.save();// 设置无边框（不需要设置QPen，因为默认是不绘制边框的）QPen pen(Qt::NoPen);// QPen pen(Qt::black, 1);painter.setPen(pen);QRect rect;int step = 50;          // 内圈和外圈的距离int sRange = 8;         // 扇形向外绘制的范围（圈数）int numSlices = 16;     // 分成多少个扇形int lenght = 2 * step;  // 矩形边长// 计算扇形的中心点、半径、起始角度和跨度角度int centerX = width() / 2;int centerY = height() / 2;// 生成颜色（这里简单地使用彩虹色）QVector<QColor> colors;for (int i = 0; i <= sRange; ++i){float hue = (float)i / sRange * 360.0f;colors.append(QColor::fromHsvF(hue / 360.0f, 1.0f, 1.0f));}// 绘制每个扇形for (int i = 0; i < numSlices; ++i){double startAngle = i * 360.0f / numSlices;double spanAngle = 360.0f / numSlices;for(int idx = 1; idx <= sRange; idx ++){QPoint startPt(centerX - idx * step, centerY - idx * step);rect.setRect(startPt.x(), startPt.y(), lenght + idx * lenght, lenght + idx * lenght);// 外圈int inRadius = idx * lenght;QRectF innerRect(startPt.x() + step, startPt.y() + step,inRadius,inRadius);// 内圈QPointF outStartPoint;outStartPoint.rx() += rect.center().x();outStartPoint.ry() = rect.center().y() - outStartPoint.y();QPainterPath path;// 创建一个QPainterPath对象path.moveTo(outStartPoint); //先移动到圆心path.arcTo(rect, startAngle, spanAngle);// 参数（矩形左上角坐标，弧的宽度，弧的高度，起始角，画多少度）path.arcTo(innerRect, startAngle + spanAngle, -spanAngle);// 参数（矩形左上角坐标，弧的宽度，弧的高度，起始角，画多少度）path.closeSubpath(); // 闭合路径（可选）painter.setBrush(colors[idx]);painter.drawPath(path);}}painter.restore();
}

执行结果如下图所示：