Re: XForms: Free object draw and redraw problem

Steve Lamont (spl@szechuan.ucsd.edu)
Fri, 1 May 98 06:08:58 PDT

# To subscribers of the xforms list from spl@szechuan.ucsd.edu (Steve Lamont) :

> I use free object option provided by fdesign to create some
> lines. These lines will change length according to the values that
> other routine defined and the values will change with time. I draw
> the lines at the handle routine using fl_line() and call
> fl_redraw_object() whenever a new set of data are
> available. However, the objects (lines) I've defined have no change,
> they remain their original shape whatever I change their value
> (x,y,x,y,col). I'm sure the pointer pointing to that free object is
> correct, but still has no effect. Can anyone tell me how to draw
> and redraw that kind of free object.

There are several questions to ask:

Are you sure that the Free object handler is being called?

Are you sure that the coordinates you're using are correct and within
the area of the Form and/or Free object?

If you are setting clipping, are you sure that the clipping bounds are
correct?

Are you clearing the Free object before you begin the refresh or
drawing?

Do other objects get properly updated or respond when clicked or
actuated by the user?

Are you returning control to the XForms main loop after you draw? If
you don't then the draw commands may be buffered and not sent to the
server. You can also periodically call fl_check_forms() if you have a
long running loop that would otherwise "hang" the application's user
interface.

spl
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