Change colour of specific item in Qwt Plot

AhmedAlshawi

Hi All,

I have developed a qwt that contains multiple QwtPlotShapeItems.

//Run a function to get an array of polygons
QVector<QPolygonF> polygonArray;
createPolygonArray(lines, polygonArray, maxdistance);

//add each polygon in the polygon array to the qwt plot
for (int j = 0; j < polygonArray.size(); j = j + 1)
{
    QwtPlotShapeItem *shape = new QwtPlotShapeItem;
    shape->setPen(QColor(0,0,0), Qt::SolidLine);
    shape->setTitle("shapeNumber_" + QString::number(j));
    shape->setBrush(QColor(130,130,130,50));
    shape->setPolygon(polygonArray[j]);
    shape->attach(&myPlot);
    V.push_back(shape);
}
myPlot.replot();

I want to return to my plot at a later point in my code and loop through all the attached QwtPlotShapeItems, and if it's title matches what I looking for, then I want to change the colour of that shape. So for example:

//.....later on in my code, in another function that the plot is passed into (by ref)
for (int j = 0; j < myPlot.numberOfAttachedShapeItems(); j = j + 1)
{
    if (myPlot.attachedShapeItem[j].Title() == "shapeNumber_7")
    {
        myPlot.attachedShapeItem[j].setBrush(QColor(0,0,0,255));
    }
}

Is this possible, or do I have to recreate my plot each time I want to change the color of a single shapeItem?

Thank you!