[XForms] How to use an idle_callback to run an animation? CODE APPENDED

[Peter Rowat]

Dear Jens,

   I have tried to follow the instructions for using an idle_callback but so 
far have been unable to make the program work.

The callback is registered in my “create_form_canvasform”, and the callback is 
declared, as per p.47 in the Library manual. 
As I understand it, the callback should be getting called continually when 
otherwise there’s nothing happening. But it is never called. My test 
idle_callback merely prints a number, no graphics at all.

I can’t see anything I’m doing wrong.

My program is derived from the demo “canvas.c”, and I’ll append a file with the 
relevant parts of the program. 
The main addition to “canvas.c” was to draw the path of the mouse in the 
canvas. 

I apologize for asking this sort of question so close to Christmas, but it’s 
been a major aim for me to have this (and much more) running by now.  Any 
suggestions greatly appreciated.  I’ll proceed to look at the xforms 
source-code.

Peter

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