4. 绘制光谱曲线QGraphicsView类

一、前言

Qt的QGraphicsView类具有强大的视图功能，与其一起使用的还有QGraphicsScene类和QGraphicsItem类。大体思路就是通过构建场景类，然后向场景对象中增加各种图元，最后利用QGraphicsView类对场景进行显示。

二、绘制光谱曲线

实现功能主要有：

1 传递点击图像行列号，然后绘制曲线，代码如下：

 void SpectralProfileDialog::AddPressSlot()
 {
     //setModal(0);
     HyperProcess *ptr = (HyperProcess*)parentWidget();
     curFileName = ptr->curFileName;
     currentRow = ptr->curRow;
     currentCol = ptr->curCol;

     if(curFileName == "")
     {
         QMessageBox::information(this,"Message Error","Current Scene IS NULL!");
         return;
     }

     if(currentCol == - || currentRow == -)
     {
         QMessageBox::information(this,"Message Error","please Select A Pixel");
         return;
     }

     cv::Mat curImg = GDALOpenCV::GDAL2Mat(curFileName);
     if(currentCol > curImg.cols || currentRow > curImg.rows)
         return;

     int count  = curImg.channels();

     std::vector<cv::Mat> curImgMat(count);
     cv::split(curImg,curImgMat);

     QVector<QPointF> pixSpectralData(count);
     double tmpMaxValue;
     double tmpMinValue;
     double maxValue = ;
     for(int c = ;c<count;c++)
     {
         cv::minMaxIdx(curImgMat[c],&tmpMinValue,&tmpMaxValue);
         if(maxValue < tmpMaxValue)
             maxValue = tmpMaxValue;
         pixSpectralData[c].setX(curImgMat[c].at<float>(currentCol,currentRow));
         pixSpectralData[c].setY(c+);
     }

     float x_scale = 1.0*(ui->spectralGraphicsView->height()-)/maxValue;
     float y_scale = 1.0*(ui->spectralGraphicsView->width()-)/count;

     QPen pen;
     pen.setWidth();
     QColor qc=QColor::fromHsl(rand()%,rand()%,rand()%);
     pen.setColor(QColor(qc.red(),qc.green(),qc.blue()));

     for(int c = ;c<curImg.channels()-;c++)
     {
         myScene->addLine(pixSpectralData[c].y()*y_scale,-1.0*(pixSpectralData[c].x()*x_scale),
                          pixSpectralData[c+].y()*y_scale,-1.0*(pixSpectralData[c+].x()*x_scale),pen);
     }
     ui->spectralGraphicsView->setScene(myScene);
 }

三、效果图