Re: Some featurerequests

[Lars Clausen <lrclause cs uiuc edu>]

On 5 Aug 2003, Sven Vermeulen wrote:
> Hi,
>
> I have some features that I'd like to see in DIA and love to help with,
> but I would like some feedback on things.
>
> The first feature is a double-line for the normal line. Currently, dia
> has LINESTYLE_SOLID, LINESTYLE_DASHED, LINESTYLE_DASH_DOT,
> LINESTYLE_DASH_DOT_DOT, LINESTYLE_DOTTED in the LineStyle. I'd like to
> have a LINESTYLE_DOUBLE or similar in it.  However, such a
> LINESTYLE_DOUBLE would probably require lots of tweaks (for instance the
> ending points of the line (ARROW_*)). Is it possible in the current code
> to "easily" add such a double-line? Or would it be preferable to create a
> special shape for it?
>
> If a seperate shape is advised, how can I make sure that this shape has
> the same possibilities as the current line wrt the ending points
> (ARROW_*) without creating a shape for each possible combination?

I don't think the arrows are so much of a problem, they can already handle
wide lines (which essentially this is), but rendering can be tricky.  It'd
be easy to make a wide black line with a narrower white line on top, that'd
even work with most output formats and with all the line types.  However,
if you want to be able to see through the middle, it gets tricky for the
non-straight lines.

> The second feature is regarding the middlemousebutton menu: currently, if
> you press the middle mouse button on a line, it gives you
>
>       Line
>       -----------------------
>       Add connection point
>       Delete connection point
>
> I'd like to have extra options that add a bridge, meaning that two lines
> that cross each other cannot confuse the users about whereto what line
> goes. As an image sais more than a thousand words, please view
> http://studwww.ugent.be/~sjvermeu/dia-0001.png. Sorry for the freehand
> draw :)

Yes, I see it.  That is a very useful thing for clarifying diagrams.

> That bridge should be moveable though, so it's like "Add corner" in the
> polyline, only it's not a corner but some small arc.

While it could be moveable by hand as easily, it'd probably make more sense
to have it be associated with the crossing line, so that if either line
moves, the bridge is moved accordingly.  In fact, that style would be
easier internally, as it doesn't require adding a new handle.

> This feature is more ease-of-use because I know I can just draw a line,
> then draw an arc, and then draw a line again, but it would be fun if I
> could do this more easily.

No, that's way more than just ease-of-use.  If there is some kind of
diagram validity checker or simulator involved, having it be an actual line
rather than three line pieces can make a lot of difference.  

It's not going to happen in this upcoming release, but it's worth keeping
in mind.  For electronics diagrams, it's an essential feature.

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| HÃrdgrim 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?