layout to svg

Hi,

I've been experimenting with ways of getting nice pictures of layouts
recently. My first attempt was to create a new display type "solid"
where all of the layers were made of solid colour rather than a pattern.
It worked nicely, but suffered because of the order of the layers - MET2
would obscure VIA1 for example and N/PPLUS would obscure DIFF.

So anyway, I've built up some skill code that runs on a layout cell view
and produces an SVG file of the visible layers which you can then open
in inkscape, the gimp or anything else that supports it. The results
look pretty good in my opinion.

Before you use it you need to create two files which tell the code which
layers to consider and which order they should appear in as well as
how they should appear. So in my case, I use top metal to cover lots of
circuitry, so I can make it slightly transparent so I can see what's
going on underneath (or I could make it non-visible in the LSW and it
wouldn't appear at all).

If you want to give it a try, you'll also have to edit the code slightly
to point it at where you have the files and where to dump the output.

One caveat - it leaves behind a library (by default this is layout2svg)
which it uses as a temporary library. Creating a library and then
deleting it again for each operation means your cds.lib would fill up
with multiple entries about the deletion, which is a bit impolite. It's
safe to delete the temporary library, or search for FIXME in the code
and enable the deletion if you're happy that it will produce excess
lines in your cds.lib.

It turned out quite large in the end and I'm a bit reluctant to post a
19k file here directly (especially after all that waffle), so I've put
it on the web at http://atchoo.org/tools/cadence/svg.il

Hope you find it useful - but don't expect it to work on large designs!

Cheers,

Roger

 

Hello Roger,

That's a nice idea I think. Nice code, too.

I understand now your need for the scratch library. I see you have made this choice of keeping the
hierarchy, but yourself state that it causes problems because instances appear below the layer from
the root cell regardless of their z-order.

So I wonder, have you considered copying the root cell to a scratch cellview, then flattening
*everything* down to level 32, then merging all shapes together. That would fix the z-order problem
as well as the need for a scratch library, tough it would probably result in a larger .svg file and
longer run time !

Also, I believe that the layer order could be read from the technology data, unless you have a
particular reason of wanting it to be overriden by the user.


Anyway, lots of thanks for sharing this code with us. When I have time, I'll give it a try to see
for myself.

Stéphane

 

One possible problem with flattening the hierarchy is the text. In the
pcells in our PDK the instance name text is a paramaterized label
[@instanceName] so when it is flattened it changes back from EX: M1
back to [@instanceName].

If you don't care about text it should be fine.

Tim

 

Very excited about this. I'm not sure how you are rendering these
but, I am not getting colour. I've reduce a file to a pretty simple
case.
this renders in black for me. This is more of an SVG issue I guess.


<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/
Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="190.5px" height="392px" viewBox="0 0 190.5 392"
xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xlink="http://
www.w3.org/1999/xlink">
<title>layout2svg - ESD_c - layout</title><desc></desc>
<defs>
<style>
..MET4drawing { fill: #990006; opacity: 0.075; }
</style>
</defs>
<polygon class="MET4drawing" points="0.65,118.9 89.85,118.9
89.85,87.75 0.65,87.75 0.65,118.9"/>
</svg>

Thanks

 

I was loading it up with firefox/mozilla with the built in SVG
capability. I also tries the Adobe
plugin as well. Both rendered black. I'll give GIMP and/or inkscape
a try.