Re: Logic Gates in SVG format for Dia

[Alan Horkan <horkana maths tcd ie>]

On Sat, 1 Nov 2003, Cyril Chevrot wrote:

> Here some logic gates in SVG format for Dia.
> The Logic section of Dia 0.92 already contains some logic gates however
> only a subset has been implemented.

> My version is more complete. It contains :
> - 10 logic gates : and/or/xor/nand/nor/nxor/inverter/buffer/mux/register
> - NMOS and PMOS transistor
> - Connection stuff
> - Comparater

I finally looked at your shapes and I have time to give some feedback (and
this is the second draft, I meant to send this on Sunday but forgot)

Nice work but ...
(and these are not really your fault)

there is a lot of redundancy in your sheet it makes it blindingly obvious
that being able to rotate shapes at least through simple 90 degree
rotations is essential.
Dia has a feature to Flip shapes vertically and horizontally but it is
hidden away in the context menu and needs to be promoted to the Object
menu (even if it currenly only works for SVG based shapes, it doesn't
belong in the context menu).  I assume you were unaware of it and that is
why you created shapes for 4 directions rather than just 2.

all your shapes were transparent when you exported them which due to a
flaw in Dia means that users cannot change the colours of the shapes.
(there are a few ways to fix this but again Dia should just work instead,
I'll describe the workarounds later if you want)

You drew some Arcs/Bridges and I vaguely recall that there was some
discussion to do this programmatically by enhancing the basic line to
allow a bridge to be added.  I dont know if any progress was made in this
direction.

Umm, I'm sure I had more to say but it is probably best that I respond
sooner rather than later, I expect I'll remember other things later.

As someone who has made a few shapes myself I have a lot of respect for
all the time and effort you must have put into your shapes.
Thanks for getting involved.

Sincerely

Alan Horkan