Drawing a vartical trace line on ChartMouseClicked event

[Himanshu]

Hi:

I wanted to draw a vertical line in the HighLow chart whenever a user clicked on it. By calling setHorizontalAxisTrace(true) on a chartPanel object, I can have a vertical line which pretty much tracks my mouse. But, what I really wanted is that when I click on a chart, it draws a vertical line at that point but does not track the mouse movements.

I tried to add the code for this by having my application implement the ChartMouseListener interface and add the following code in the event handler.

public void chartMouseClicked(ChartMouseEvent event)
{
int x = event.getTrigger().getX();
int y = event.getTrigger().getY();

drawVerticalLine(x);
}

where drawVerticalLine does exactly what the private function, drawHorizontalAxisTrace() does in the ChartPanel class. ( I would have liked to call it but it is a private function)

However what I see is that the line is drawn when I click on the chart but it is immediately erased. Next time I click on a point in the graph, it draws a vertical line where I click and ALSO a line where I last clicked, but again immediately erased. It seems to me that the chart is automatically refreshing itself after a mouse click and erasing whatever is temporarily drawn. Is there a way to get around this?

- Himanshu

[David Gilbert]

The tracing lines are part of the ChartPanel. You probably need to use cross hairs, which is in the ValueAxis class. Try the setCrossHairVisible(boolean) method.

I have to say I've lost track of how both of these features work, when I get a chance I'll sit down and write up some documentation for them, and iron out some more bugs/inconsistencies.

Regards,

DG.

[Himanshu]

Hi David,

I tried to use the setCrossHairVisible(true) method, but somehow I did not see the cross-hair on either the horizontal axis or vertical axis. I do it before drawing the plot, just like in the

Do you know why?

- Himanshu