Re: gEDA-user: Snap-to-pins, was: Stupid newbie question

[Chad Robinson <crj@lucubration.com>]

Ales wrote:
> The way I see things, there are two ways of implementing the snap
> to pin/net:
>
> 	1. As the user draws nets, automatically snap to the nearest pin/net.
> 	   This would require a switch to turn this behavior off.  
> 	2. The mechanism that Dan pointed out above.  Nice because
> 	   it keeps the existing net drawing behavior while providing
> 	   a nice way of getting the desired snap to nearest. Though,
> 	   it might require net routing algorithm if we want to deal
> 	   with strictly ortho nets.
>
> 1. is probably easier to implement at this stage though you might be 
> able to make some assumptions/simplifications to make 2. just as easy.
>
> Also, for now, I would only worry about snapping to the endpoints of
> pins and nets.  I don't think it is worth the effort (at this point)
> to try to snap to the middle of nets or buses).
Since the SHIFT key is not checked as a modifier during net drawing, what I've 
done is integrated a check just below where the CONTROL key is looked for. 
That way the snap behavior is optional. I have an iterator doing what you 
described in your other e-mail message, basically just looking through every 
object and checking its endpoints if it's an OBJ_PIN. It also "drills into" 
OBJ_COMPLEX types looking for pins, although I wasn't sure if this was really 
important.

As I got into the structs and found where they were defined, everything 
started making a lot of sense. I used to do a lot of MUD development and 
having thousands of linked lists of structs all over the place is second 
nature to me. I've got a bug in it right now that's not finding the right 
endpoint coordinates but when I get it fixed I'll let everybody know, then you 
can show me the "right" way Ales.

Thanks, and regards,
Chad