Re: Electronics with DIA (was: Other diagram types)

[Lars Clausen <lrclause cs uiuc edu>]

On Sat, 25 Jan 2003, jonni@lehtiranta.net wrote:
> 
> Greets again!
> 
>> I have a bunch of updated Logic shapes at home, mostly involving better
>> icons, but also with the horizontal/vertical distinction.  I'm not
>> putting them in right now as we're in a feature freeze, but I can send
>> them to you.
> 
> Please do! jonni@lehtiranta.net.
> The actual shapes I was after are symbolic representations for
> electric components. These include for example adders, latches,
> multiplexers and so on, and it looks like I'll end up drawing
> these myself =).

Oh, I see.  Yeah, those don't exist yet.  I've been looking at textbooks
occasionally, saying "I oughta make these," but never got started.

>> > 	I'd also like the option to specify both a name and
>> > 	a "number-of-wires" info to an arrow and get them to
>> > 	print nicely.
>>
>> Let me see if I understand you right: You want something that can have
>> an arrow in one end, but a number of lines in the other, and that shows
>> a name and the number of lines?  Or something else?  Can you do a
>> mock-up perhaps?
> 
> Hm, let me clarify =). I'd need a way to mark up
> 
> 1) connecting two components with many wires
> 	example: mainboard to harddisk, IDE, 80 wires =)
> 
> _____________        80        ________
> | Mainboard |--------/-------->| disk |
> -------------                  --------

That'll be easy!  A number of lines have labels (movable), and the slash
will be simple enough to render.

> 2) connecting one "parallel bus"-type output to many different
> 	components; maybe connecting two joysticks might serve
> 	as an example =). Real uses (for me) include sending different
> 	bits of an opcode to different places in a processor; some
> 	bits always choose registers to use, some go to the control
> 	and so on.
> 
> ____________
> | computer |
> ------------
>       |           bits 0-7
>       |----------------->
>       |           bits 0,8-14
>       |----------------->
> 
> Also, of course, it wouldn't be a BUS without a way to send all the
> bits to many places.

So something that's kinda like the bus in the Network sheet, but with
zig-zag lines and labels?  Shouldn't be too hard, either.

>> > - What about LINES? I didn't find a "perfect line"
>> > 	anywhere. The UML message is a good arrow but it
>> > 	doesn't snap with another line, so building L-shaped
>> > 	connections seem impossible (to do well).
>>
>> I don't get what you mean by 'perfect line'.  What can you do with one?
>> What would it look like?  Have you tried the zigzagline?
> 
> It would like a line with an arrow at one end, text option at both
> ends, and a wire number indicator in the middle. Also, either having
> snap points for branching or another way to do branches would be great.

All very doable.  The standard line shows how to add snap points, or you
can do like the Network -- Bus object that allows adding more lines.

> Now, graphically, the DIA zigzag looks like this:
> 
> 
>  |          |
>  |          |
>  `----------
> 
> or
> 
>  |
>  ------------
>             |
> 
> or the same thing upside down. I didn't even find a way to make it
> 
>  ------
>       |
>       ---------
> 
> without adding a segment.

There is partial support for automatic swapping like this in CVS, but only
at creation time.

> Now, what I originally meant, was an L-shaped line that would do the
> adjustments needed at the corner. I can get the zigzagline look this
> way with careful work, EXTRA careful if the line has an arrow at either
> end.

I don't see what's all careful about it.  With the mouse over one end,
delete a segment, and it's L-shaped.  Not as good as it happening
automagically, of course.

> I'd still fancy the option of having one end of the line
> horizontal and the other vertical, and getting the corner automatically
> where it belongs.

Autolayout is really what you and a lot of us want.  It's high on my list,
but not as high as getting the next release out.

> --------
> 
>> I was also dissatified with the Circuit shapes as I didn't think
>> they looked good enough to do professional drawings so I
>> modified and created additional shapes.  I posted them on
>> the Dia List awhile back and are available from my webspace at:
>> http://www.hal-pc.org/~jsgil/Dia-Shapes.tar.gz
>>
>> John
> 
> Thanks, John! Still, I'm afraid that wasn't what I was after =I.
> 
>> I am working on line decoration code that should make it easy to specify
>> names as well as 'bus-width/number-of-wires' slashes that stay centered
>> on the line.  I'm a bit busy, so it will be a few weeks before I can
>> get out a semi-user-friendly version, but the
>> code is mostly written and works well.  This same decoration code will
>> make it possible to create clock-input lines that can be stuck on
>> flip-flops, or (NOT) bubbles that can be added to any gate input.  I
>> might  be able to hack the code so that decorated lines can be stuck
>> together with fixed user-specified angles.  Stay tuned.
>>
>> Dave Hoover.
> 
> Hey, that sounds like what I need =). I'll stay tuned..

You guys should either send the code to the list or at least to each other,
so you can work together on it.

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| Hårdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?