QCustomPlot基础教程（八）——QCustomPlot将绘制的图形保存导出

一、函数介绍

QCustomPlot提供了四种常用的save接口，其格式如下：

saveBmp(const QString &fileName, int width, int height, double scale, int resolution, QCP::ResolutionUnit resolutionUnit);
saveJpg(const QString &fileName, int width, int height, double scale, int quality, int resolution, QCP::ResolutionUnit resolutionUnit);
savePng(const QString &fileName, int width, int height, double scale, int quality, int resolution, QCP::ResolutionUnit resolutionUnit);
savePdf(const QString &fileName, int width, int height, QCP::ExportPen exportPen, const QString &pdfCreator, const QString &pdfTitle);

二、代码示例

首先在UI界面中创建一个按钮控件，其ObjectName为pbn_save，然后在mainwindow.cpp中写入如下代码：

bool MainWindow::on_pbn_save_clicked()
{
    QString filename = QFileDialog::getSaveFileName();

    if( filename == "" ){
        QMessageBox::information(this,"fail","保存失败");
         return false;
     }
     if( filename.endsWith(".png") ){
         QMessageBox::information(this,"success","成功保存为png文件");
         return ui->customPlot->savePng( filename, ui->customPlot->width(), ui->customPlot->height() );

     }
     if( filename.endsWith(".jpg")||filename.endsWith(".jpeg") ){
         QMessageBox::information(this,"success","成功保存为jpg文件");
         return ui->customPlot->saveJpg( filename, ui->customPlot->width(), ui->customPlot->height() );

     }
     if( filename.endsWith(".bmp") ){
         QMessageBox::information(this,"success","成功保存为bmp文件");
         return ui->customPlot->saveBmp( filename, ui->customPlot->width(), ui->customPlot->height() );

     }
     if( filename.endsWith(".pdf") ){
         QMessageBox::information(this,"success","成功保存为pdf文件");
         return ui->customPlot->savePdf( filename, ui->customPlot->width(), ui->customPlot->height() );

     }
    else{
     //否则追加后缀名为.png保存文件
         QMessageBox::information(this,"success","保存成功,已默认保存为png文件");
     return ui->customPlot->savePng(filename.append(".png"), ui->customPlot->width(), ui->customPlot->height() );

    }
}

对上述代码进行简单介绍，首先定义QString类型的filename存放用户想要保存的文件名称，然后检测文件名后缀，如果是png，jpg，jpeg，bmp，pdf结尾，则图像保存为该格式，否则默认图像保存为png格式文件，并弹出相应保存成功或保存失败的提示信息。

参考：https://vimsky.com/examples/detail/cpp-ex—QCustomPlot-savePdf-method.html