gEDA-user: paper to paper.pcb -- science fiction? science fact? youdecide..

[John Griessen <john_g@cibolo.com>]

On Sat, 2004-01-24 at 14:51, Bob Paddock wrote:
> Is there any way to past this GIMP image, in any format, into the PCB program, 
> so that it can be edited as a real PCB?

Not as pcb stands.

It would be nice to be able to display a PNG bitmap image along with your pcb vector 
based drawing while you edit it.  I've tried reading the pcb source and it's too 
knotty for me to see a way to add this feature as yet.  

Tools exist now, (see apache FOP project ), to  convert back and forth between   
postscript and XML-svg, and I think there is some kind of OSS 
like Adobe Streamline that will trace around contour lines of contrast in an image.

In the future, I can see a OSS XML-svg based layout tool that defines 
paths as outlines rather than from center lines like pcb does.   We define
outlines in chip design, not centerlines, so why not for board layout?
Then the layout data will be transformable to postscript, and to SML-svg.
So, I think we have tools now to get the outlines into XML-svg form
like the layout database will use, (all futuristic And then talk from here...).    
And then scanned bitmaps could quickly become vector art that was 
slightly off grid.  And then you could use tools to nudge, tweak, and 
snap2grid until you had an editable, design-rule-checkable layout 
from any scribbled, painted, xeroxed, spy camera photographed, 
faxed, brass-rubbed-transfer or some such reverse-engineering-starting-point.

I have seen no transformation between vector drawings based on 
outlines of shapes to vector drawings based on centerlines of shapes,
but that would be a very low loss transform given enough floating 
point precision, and it would not require any fuzzy logic or deep thinking,
so maybe we could make a script to do this right away?  Anyone got a quick 
start on that?  {Yes, this is a puzzle-solving challenge to all you programmers 
out there:  Write a ghostscript program that transforms postscript arcs, lines,
strokewidths, stroke-colors, fills, fill-colors into a pcb file such that the postscript
drawing layers that are stacked and cover eachother are separated in the output
as layer numbers instead of colors.  perhaps depend on using only
 single layer files,(multiple files per layout to get the layout layers)   It would not be 
on a pcb grid, but that can be a separate issue}


A way to work with your data and geda tools as is now:
1.    open pcb and create a matching board outline and print it as gerber to 
a defined place where each change will overwrite the last with one print mouse-click.
2.  use gimp to create a two layer png based document such that one layer can be reloaded 
from a png file
3.   open gerbv in the gerber output directory from pcb this way:    gerbv  *.gbr
4.  From gerbv, export to png
5.  Load the gerbv exported file into gimp with superposition and transparency controls
	set to your liking.    Get offsets right so things overlap with good registration.
6.   Use gimp to print your final  board art in postscript form.  
 (gerber output not possible by this tool-flow -- See programmer challenge above!)



John G



-- 
John Griessen    Cibolo Design       Austin Texas
EE good at IR systems, power supplies, logic design, A2D D2A, digital amps, 
mechatronics, SiGe and CMOS layout, MEMS/mech/electronic/photonic 
modeling, charge pump PV/battery/fuel cell power converters, linux counter #249315