Slow VI when inserting a background picture

[Skeivoere]

I am trying to draw a graph on top of an image. (A boat sailing on a map).
When I put the picture as a background on a graph, or behind a graph, my VI slows down. It seems to me like the picture is being updated in every timestep. How can I avoid this? The picture is static, and should only be drawn once.

[Greg_McKaskle2]

> I am trying to draw a graph on top of an image. (A boat sailing on a
> map).
> When I put the picture as a background on a graph, or behind a graph,
> my VI slows down. It seems to me like the picture is being updated in
> every timestep. How can I avoid this? The picture is static, and
> should only be drawn once.

Each time the graph is sent new data it needs to erase the current plot
before it draws the new data. For transparent graphs, erasing is done
by redrawing the image behind it.

You might want to investigate different formats for the graphics as that
can make a big difference. True color graphics tend to take longer to
draw, though it isn't as bad if it matches the monitor resolution.

If you have additional questions, please provide more de
tails.

Greg McKaskle

[Skeivoere]

Thanks!

I have tried a lot of formats, but the VI always slows down. What I want to do is make a display for shipsimulations, where the current position is given as input to the system. This position is then shown in an xy-graph. To make it more realistic, I want the position to be shown in a map.

The way I have done it is to represent the ship as a point in the graph, make the graph transparent and use the picture as the background of the graph.

Is it possible to tell LV not to redraw the picture? Or is there some other trick that can allow me to show the moving point on top of a picture? Or is it just not possible to do this?

Jorgen

[Ben]

When i first read your post I tried to create a VI tht showed the slow down.

I was un-able to do so.

Could you post your code so we can take a peak?

THe only thing that comes to mind otherwise is that maybe you are updating the graph to often for the machine you are using. If this is the case, a well placed delay may do the trick.

Ben

[ian_fung]

Not sure if this link helps you...

http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000C1850000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0&USEARCHCONTEXT_QUESTION_0=Graph+background&USEARCHCONTEXT_QUESTION_S=0