Re: using dia-lib for a simple program

[Hans Breuer <hans breuer org>]

At 16.03.2012 13:00, julienjavaloyes yahoo fr wrote:
> dear Dia developer,
>
> I would need to make a small specific C (or C++) program.
> Depending if I take the good or the bad path, I can have this done in 2 years or 2 weeks.
Sorry, I don't get these estimations.
  Good -> 2 years -> implemented everything yourself?
  Bad -> 2 weeks -> using what? An exisiting library providing
    everything you want in an easy consumable fashion?

> This is why I would greatly appreciate your advices.
>
>
> The program must do the following.ï
>
> - Open a main window with a simple toolbar containing a few elements.
I don't think any of the Dia code could help here.

> --- The element "Square" with two connectors (input/output)
objects/standard/box.c ?

> --- The element "triangle" with three connectors (2 inputs/1 output)
objects/standard/polygon.c ?

> --- Maybe a few variations.
>
> - Drag and drop and connect the elements.
app/disp_callbacks.c (and more)

> - The elements should be clickable to define some parameters (here, some floats and ints )
app/display.c (and more)

> - Savingï the elements properties.
> - Saving the connectivity of the diagram (ideally) in a boolean matrix connecting all output to all inputs.
Dia's native format is assembled in app/load_save.c and that's currently 
the only file format preserving connections.

> I am happy to get comments only at the level of the C program. How to do that ?
>
> So far, my best bet is to use GTK and dia-lib. Is is a good idea ? Is it possible to use dia-lib ?
If you are asking for a simple SDK version managed by us, see:
http://mail.gnome.org/archives/dia-list/2012-January/msg00071.html

In short: there is no single dia-lib which could provide what you listed.
If you decide to split the useful bits from Dia's code base you would be on 
your own.

> However, just in order to give you the full picture,
> [...]
> I don't know if this library scavenging attitude is encouraged.
I'd say it is neither encouraged nor discouraged - the GPL allows
to do that and that fine. Of course Dia would benefit much more
from contributions than from reusing parts.

> Howevercredit to dia and dia-lib will be paid of course.
Maybe you should take a closer look at Dia's architecture - at least I 
don't quite get the split you are making between Dia and dia/lib ...

Regards,
        Hans

-------- Hans "at" Breuer "dot" Org -----------
Tell me what you need, and I'll tell you how to
get along without it.                -- Dilbert