kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxxxx>]

On 6/4/2014 2:33 PM, Lorenzo Marcantonio wrote:
> On Wed, Jun 04, 2014 at 02:20:12PM -0400, Wayne Stambaugh wrote:
>> user confusion.  Where would you save them in the old kicad_pcb file
>> format after you made changes?  If Pcbnew where a read only application,
>> then this would be less of an issue.
> 
> That's why I questioned if it would be desiderable...
> 
> The only thing I think would be possible to keep *backward*
> compatibility is using optional forms, so if you don't use that feature
> the file remain compatible (no strange layers and the file still loads).
> I changed the quotation rules for the sexp in a backward compatible way
> and now they are both LISP and kicad compatible.

Backwards compatibility is not optional.  We should always be able read
older board and footprint file formats.  That was one of the things that
drove the design of the current layer parsing of legacy boards and the
design of the new layer sexpr format.

> 
> PDF works in this way (unknown features are simply ignored), but it's
> designed to be an 'append only' format. And obviously javascript doesn't
> work in xpdf. However a PDF editor changing the rest of the file would
> probably break the javascript stuff (at most it could preserve the script
> object, but all the anchors could be broken...)
> 

I think we should steer the discussion towards defining what
improvements we need to make to the board and footprint file formats to
support the changes we have been discussing.  Once that is defined, we
can discuss the code changes required to handle the new layer
definitions.  Everything else depends on getting this correct.  Here is
a sample layer definition:

  (layers
    (15 F.Cu signal)
    (0 B.Cu signal)
    (16 B.Adhes user)
    (17 F.Adhes user)
    (18 B.Paste user)
    (19 F.Paste user)
    (20 B.SilkS user)
    (21 F.SilkS user)
    (22 B.Mask user)
    (23 F.Mask user)
    (24 Dwgs.User user)
    (25 Cmts.User user)
    (26 Eco1.User user)
    (27 Eco2.User user)
    (28 Edge.Cuts user)
  )

>From the discussion, it sounds like we would need to add an F.KeepOut
and B.KeepOut for courtyard areas.  Maybe add F.KeepOutZ and B.KeepOutZ
for vertical keep out areas to prevent pick & place machine plunger
crashes on tall components.  It also sounds like folks are interested in
naming layers so we can optionally add a (name "My Layer Name") element
to the layer.  This would allow users to define their own names for
display purposes.  The only thing I'm not sure of is layer pairing that
was being discussed.  I would need a example of how that could be used.
 So that would give us something like:

  (layers
    (15 F.Cu signal (name "Front copper layer"))
    (0 B.Cu signal)
    (16 B.Adhes user)
    (17 F.Adhes user)
    (18 B.Paste user)
    (19 F.Paste user)
    (20 B.SilkS user)
    (21 F.SilkS user)
    (22 B.Mask user)
    (23 F.Mask user)
    (24 Dwgs.User user)
    (25 Cmts.User user (name "I put my comments here!"))
    (26 Eco1.User user)
    (27 Eco2.User user)
    (28 Edge.Cuts user)
    (33 F.KeepOut user)   # This could be any number > 32
    (34 B.KeepOut user)   # This could be any number > 32
    (35 F.KeepOutZ user)  # This could be any number > 32
    (36 B.KeepOutZ user)  # This could be any number > 32
  )

You could use *.KeepOut and *.KeepOutZ for any module drawing element
(lines, arcs, circles, etc.) that are defined on both sides of a board.

This should be a good start to get the discussion moving in the right
direction.

Wayne