c++ - QTextDocument 中的 QChart

Question

我想生成一个包含文本和 QChart 的 pdf 报告。我目前使用 QTextDocument 并将图表作为图像添加到其中，然后我使用 QPdfWriter 导出为 pdf。

#include <QtGui>
#include <QtCore>
#include <QApplication>
#include <QtCharts/QChartView>
#include <QtCharts/QLineSeries>
using namespace QtCharts;

int main(int argc, char *argv[])
{
QApplication a(argc, argv);

// Create a chart
QLineSeries *series = new QLineSeries();
series->append(0,0);
series->append(1,1);
QChart *chart = new QChart();
chart->addSeries(series);
chart->createDefaultAxes();
chart->axisX()->setTitleText(QString("x [m]"));
chart->axisY()->setTitleText(QString("y [m]"));
chart->setTitle("Simple chart example");
chart->resize(500,500);

// Paint the chart into an image
QImage img(500,500,QImage::Format_RGB32);
QPainter painter(&img);
QChartView *chartView = new QChartView(chart);
chartView->setRenderHint(QPainter::Antialiasing);
chartView->show();
chartView->render(&painter);

// Set up pdf writer
QString filename = "myfile.pdf";
QPdfWriter writer(filename);
writer.setPageSize(QPagedPaintDevice::A4);

// Create the document
QTextDocument doc;
QTextCursor cursor(&doc);
cursor.insertText(QString("some text\n"));
cursor.insertImage(img);
// Print the document
doc.print(&writer);

return a.exec();
}

虽然它有效，但我想避免将图表转换为图像，因为它会破坏图像质量。有办法吗？

Answer 1

这是一个解决方法，如果图像质量真的很重要:您可以直接在 TextDocument 上使用 QPainter。它需要更多的工作和调整，但质量不会丢失。

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);


    // Create a chart
    QLineSeries *series = new QLineSeries();
    series->append(0,0);
    series->append(1,1);
    QChart *chart = new QChart();
    chart->addSeries(series);
    chart->createDefaultAxes();
    chart->axisX()->setTitleText(QString("x [m]"));
    chart->axisY()->setTitleText(QString("y [m]"));
    chart->setTitle("Simple chart example");
    chart->resize(500,500);

    QChartView *chartView = new QChartView(chart);
    chartView->setRenderHint(QPainter::TextAntialiasing);
    chartView->show();

    // Set up pdf writer
    QString filename = "myfile.pdf";
    QPdfWriter writer(filename);
    writer.setPageSize(QPagedPaintDevice::A4);

    // Create the document
    QTextDocument doc;

    QPainter painter(&writer);
    QFont font = painter.font();
    font.setPixelSize(200);
    painter.setFont(font);

    painter.drawText(QPoint(700,100),"Some text");
    chartView->render(&painter);

    doc.drawContents(&painter);
    return a.exec();
}