mouse tracer CustomPlot

[A Former User]

I must build a mouseTracer like this:
https://www.youtube.com/watch?v=BzK1DmJPbuk

my problem it's that my marker follows the graph jerky..i built the graph with a vector x of double numbers and a vector y of randon numbers and I wrote:

double x = (ui->Grafico->positionX);
int j;
double u;
for (int i=0; i<1000; i++)
{
if (abs(xalt[i] - x)<0.1)
{
u= xalt[i];
j=i;

   }

}

ui->Grafico->positionY = f_altezza[j];
/QString h= QString::number(x);
QString a = QString::number(f_altezza[x])/

/*qDebug()<<"x"<<h<<endl;
qDebug()<<"funz"<<a<<endl;
qDebug()<<"funz1"<<f_altezza[33]*/

if((ui->Grafico->mouseMarkerX) && (ui->Grafico->mouseMarkerY))
{
ui->Grafico->mouseMarkerX->point1->setCoords(ui->Grafico_Altezza_LdC_Acquisizione->positionX, 0);//VERTICALE
ui->Grafico->mouseMarkerX->point2->setCoords(ui->Grafico_Altezza_LdC_Acquisizione->positionX, 1);//VERTICALE
ui->Grafico->mouseMarkerY->point1->setCoords(0, ui->Grafico->positionY);//ORIZZONTALE
ui->Grafico->mouseMarkerY->point2->setCoords(1, ui->Grafico->positionY);//ORIZZONTALE
}
ui->Grafico->replot();

[A Former User]

@mrjj I solved

[mrjj]

Hi
If you call this in mouseMove and
execute the 1000 loop each time, it might be the reason for it being jerky.

[A Former User]

@mrjj so how I must do to obtain like in the video

[mrjj]

@vale88
Sorry, i have no idea about that as i dont know the class you used or what you are
actually doing with it.
However, to follow the graph data on Y,
i would assume you would ask the Plotter what y is from an x value.

[A Former User]

@mrjj I solved

[mrjj]

@vale88
Super :)
Could you show how you did, so future readers might benefit ?

[A Former User]

@mrjj

void MainWindow::Tracer_Acq()

{

double x = (Grafico->positionX);
int j;
double u;
double posX;


QString h = QString::number(x,'f',2);
double x1 = h.toDouble();
for (int i=0; i<1000; i++)
{
    if  (abs(xalt[i] - x1) <0.001)
    {

       u= xalt[i];
       j=i;

       Grafico->positionY = f_altezza[j];
       posX = xalt[j];
       if((Grafico->mouseMarkerX) && (Grafico->mouseMarkerY))

       {
          Grafico->mouseMarkerX->point1->setCoords(Grafico->positionX, 0);//VERTICALE
          Grafico->mouseMarkerX->point2->setCoords(Grafico->positionX, 1);//VERTICALE
          Grafico->mouseMarkerY->point1->setCoords(0,Altezza_acq_bis->positionY);//ORIZZONTALE
          Grafico->mouseMarkerY->point2->setCoords(1, Grafico->positionY);//ORIZZONTALE


          QString x_text = QString::number(Grafico->positionX,'f',2);
          QString y_text = QString::number(Grafico->positionY);

          QString coord_p = QString("%1, %2").arg(x_text,y_text);
          QCursor cursor;
          QToolTip::showText(cursor.pos(),coord_p,this,QRect(),2000);

       }}


    }
      Grafico->replot();
 }

it isn't completely solved but better I don't know if it's possible