Re: Dynamic Arrows

[Cyrille Chepelov <cyrille chepelov org>]

Le Thu, Jan 31, 2002, à 09:05:43PM -0600, Richard Rowell a écrit:

> I have been hacking on a way to allow "arrows" to be loaded at runtime  
> rather then hardcoded.  Each arrow is made up of "strokes" where each stroke 
> can be a line, polyine, bezier curve/path, circle, ellipse, or a polygon with 
> filled and non-filled options where appropriate.  Most all of the rendering 
> stuff is in place and seems to work great, prints well, exports well (to PNG 
> at least), etc.

Sounds great !
How are theses strokes described ? (SVG ?)

> The next part I'm going to hack in is the loading of the "arrow" file or 
> files.  If the powers at be think this piece of code might be incorporated 
> into the "core" code, then I would like suggestions on issues such as:
> 

> 1.  Where a good place to initialize the list would be.
> 2.  Is there a preferred method of storage for global lists such as this. 

You could imitate what the shape-loading code does (without the need to make
this modular, ie you can put that in lib/ IMO. Perhaps even in a
subdirectory of lib, like lib/arrows if you need several compilation units.
I should have done this for properties.)

> 3.  What to do if an arrow is specified in a document that the local machine 
> doesn't have?

Same as when a document is loaded with a shape the local machine doesn't
have [*]

> 4.  Should Dia embed non-standard arrow definitions into the saved document 
> to avoid #3?

Same as the shape code [*]


[*] This means: warning, nasty moving target. Currently, we don't embed, but
there have been repeated expressions of interest for this feature. Kivio
does this, IIRC. Safe bet would be: make it run without embedding, but don't
make this too difficult to add afterwards. Ideally, a shared facility for
embedding/loading on the fly could be added.

	-- Cyrille 


-- 
Grumpf.