ASE Home Page Products Download Purchase Support About ASE
ChartDirector Support
 Forum HomeForum Home   SearchSearch

Message ListMessage List     Post MessagePost Message

  ScatterLayer on a Finance Chart.
Posted by GCain on Dec-22-2011 08:30
| Reply | Monitor
Attachments:
Hi,

I am trying to add some indicators onto a Finance chart at specific X Y points.

The finance chart draws correctly (image1) but when I add a scatter layer (code below)
the chart ends up looking like image2. The scatterlayer gets added
later; ie. When the user decides; usually after the chart has been rendered.


--//Code--

    double Xvalues[mySignals.count()];
    double Yvalues[mySignals.count()];
    char *labels[mySignals.count()];
    for(int i=0;i<mySignals.count();i++){
        QStringList rec = mySignals.value(i).split("|");
        QDateTime dateTime;
        /* choose correct date format */
        if(rec.value(0).lenth() == 8){
            dateTime = QDateTime::fromString(rec.value(0),"yyyyMMdd");
        }else{
            dateTime = QDateTime::fromtime_t(rec.value(0).toDouble());
        }
        if(rec.value(2) != ""){
            Xvalues[i] = QDateTimeToChartTime(dateTime);
            Yvalues[i] = rec.value(1).toDouble();
            labels[i] = rec.value(0).toLocal8Bit().data();
        }else{
            Xvalues[i] = QDateTimeToChartTime(dateTime);
            Yvalues[i] = Chart::NoValue;
            labels[i] = NULL;
        }
    }
    ScatterLayer *buylayer = myMainChart->addScatterLayer(DoubleArray(Xvalues,sizeof(Xvalues)/sizeof(Xvalues[0])),
                                                          DoubleArray(Yvalues,sizeof(Yvalues)/sizeof(Yvalues[0])),
                                                          "ALERT", Chart::CircleSymbol, 10, 0xFFFFFF, 0x000000);


/* myMainChart gets created when the
original finance chart is rendered like this;*/

myMainChart = c->addMainChart(((this->parentWidget()->height()-40)-220)-(delHeight));

--//Code//--

I am using Qt 4.7 with MingW 4.4 on W7.

The problem appears to be stemming from the X-axis not being in scale, but I can't work
out where I am going wrong.

Thanks in advance!
image1.png
image2.png

  Re: ScatterLayer on a Finance Chart.
Posted by GCain on Dec-22-2011 09:46
| Reply | Monitor
Hi Peter,

I changed the Xvalues[] array to represent 0-mySignals.count(); and everything lines up.

Originally I was using the date which appears to be incorrect.

So I guess this has been solved unless you can see I am using the component incorrectly or
there is a better way to achieve this.

Kind Regards,
GCain.


ps. Great product, unbelievable support. Thanks.

  Re: ScatterLayer on a Finance Chart.
Posted by Peter Kwan on Dec-23-2011 01:22
| Reply | Monitor
Hi GCain,

You are absolutely correct. For a FinanceChart (as well as any chart that uses a label based x-axis), the x-coordinate is 0, 1, 2, 3, .... for the first, second, third, fourth point ....

Regards
Peter Kwan