Qt：具有分类角轴的极坐标图答案

【问题标题】：Qt: QPolarChart with categorial angular axisQt：具有分类角轴的极坐标图
【发布时间】：2018-04-24 11:04:06
【问题描述】：

我想将 QPolarChart 中角轴的度数替换为附图中显示的一些文本（例如，而不是 90.0 ->“Cat 1”）。我尝试了 QCategoryAxis，但在这种情况下，类别出现在轴之间（例如 90 到 180 度之间）。

现在我使用以下代码来创建极坐标图：

QPolarChart *chart = new QPolarChart();

QValueAxis *angularAxis = new QValueAxis();
angularAxis->setRange(0, 360);

QLineSeries *series1 = new QLineSeries();
series1->append(0, 60);
series1->append(90, -60);
series1->append(180, 50);
series1->append(270, 62);
series1->append(360, 60);

QLineSeries *series2 = new QLineSeries();
series2->append(0, 0);
series2->append(90, 0);
series2->append(180, 0);
series2->append(270, 0);
series2->append(360, 0);

chart->addSeries(series1);
chart->addSeries(series2);
chart->addAxis(angularAxis, QPolarChart::PolarOrientationAngular);

ValueAxis *radialAxis = new QValueAxis();
radialAxis->setTickCount(9);
radialAxis->setLabelFormat("%d");
chart->addAxis(radialAxis, QPolarChart::PolarOrientationRadial);

series1->attachAxis(radialAxis);
series1->attachAxis(angularAxis);
series2->attachAxis(radialAxis);
series2->attachAxis(angularAxis);

radialAxis->setRange(-100, 100);

QChartView *chartView = new QChartView();
chartView->setChart(chart);
chartView->setRenderHint(QPainter::Antialiasing);

ui->mainPlot->addWidget(chartView);

【问题讨论】：

标签： c++ qt qt5 qchart qchartview

【解决方案1】：

解决方案是使用QCategoryAxis，但在QCategoryAxis::AxisLabelsPositionOnValue 中使用labelsPosition。

#include <QApplication>

#include <QtCharts>
using namespace QtCharts;

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QPolarChart *chart = new QPolarChart();

    QCategoryAxis *angularAxis = new QCategoryAxis;
    angularAxis->setLabelsPosition(QCategoryAxis::AxisLabelsPositionOnValue);
    angularAxis->setRange(0, 360);
    angularAxis->append("Cat 1", 90);

    QLineSeries *series1 = new QLineSeries();
    *series1 << QPointF(0, 60) << QPointF(90, -60) << QPointF(180, 50) << QPointF(270, 62) << QPointF(360, 60);

    QLineSeries *series2 = new QLineSeries();
    *series2 << QPointF(0, 0)<< QPointF(90, 0) << QPointF(180, 0) << QPointF(270, 0) << QPointF(360, 0);

    chart->addSeries(series1);
    chart->addSeries(series2);
    chart->addAxis(angularAxis, QPolarChart::PolarOrientationAngular);

    QValueAxis *radialAxis = new QValueAxis();
    radialAxis->setTickCount(9);
    radialAxis->setLabelFormat("%d");
    chart->addAxis(radialAxis, QPolarChart::PolarOrientationRadial);

    series1->attachAxis(radialAxis);
    series1->attachAxis(angularAxis);
    series2->attachAxis(radialAxis);
    series2->attachAxis(angularAxis);

    radialAxis->setRange(-100, 100);

    QChartView *chartView = new QChartView();
    chartView->setChart(chart);
    chartView->setRenderHint(QPainter::Antialiasing);

    chartView->show();

    return a.exec();
}

【讨论】：