[FF] - 2009-02-18 - This [widget] is a [canvas] specialized for dataflow [http://en.wikipedia.org/wiki/Dataflow] software. It features high level operations, as adding, moving, editing, removing, connecting and track objects. Other relevant features include: [OO]-design (by using the new [TclOO], completion, gui objects, (minimal) internal dataflow capability.

The class loading mechanism is defined in DataflowCanvas::enumClasses. By default it looks for subclasses of DataflowClass, so it is possible to add classes which specify how many inlet/outlets object instances will have, and manage their initialization parameters.

[http://dev.gentoo.org/~mescalinum/tclwiki-img/DataflowCanvas01.png]

Source code:


****Checkout****
======

svn co https://dataflowcanvas.svn.sf.net/svnroot/dataflowcanvas/trunk/DataflowCanvas/

======
****or browse online:****
http://dataflowcanvas.svn.sf.net/viewvc/dataflowcanvas/trunk/DataflowCanvas/


----
Example: we are going to create a `+` class, which performs the `f(x, y) = x + y` function, so it has two inlets (inbound connections), and one outlet (outgoing conn.).

======
oo::class create + {
    superclass DataflowClass
    method setup {args} {
        my variable state
        set state {0 0}
        return {inlets 2 outlets 1}
    }
    method inlet {n args} {
        my variable state
        lset state $n $args
        if {$n == 0} {
            my outlet 0 [expr [join $state +]]
        }
    }
}
======

The resulting patch:

[http://dev.gentoo.org/~mescalinum/tclwiki-img/DataflowCanvas02.png]

`entry` and `scale` classes (found in source distribution) have been used to interact with the object

----
[Drawing Diagrams] may be related to this package

----
[AMG]: Interesting.  I am working on a project that has a dataflow model.  Perhaps I can find some inspiration in your work, and maybe I can even use it as a graphical front-end.  Will you post a link to the sources soon?

[FF]: Ooops! I forgot. Sources are hosted at http://dataflowcanvas.sf.net (SVN). Btw I tried it on my PDA (400 MHz) and doesn't perform very well, perhaps because I reimplemented lot of canvas functionality by myself, because Tk [canvas] does not track current item while mouse is grabbed (see bug [http://sourceforge.net/tracker/index.php?func=detail&aid=2543460&group_id=12997&atid=112997]) (although is possible to do it in pure Tcl... just a Tk [canvas] oddity). Needs some optimization. I'm happy if you use it, and more happy if you can improve it somewhat and share your changes.

[AMG]: Oh yeah, I remember discussing that with you in #tcl before you filed the bug report.

----
!!!!!!
%| [category widget] |%
!!!!!!
----
'''[Geoffm] - 2009-08-25 07:16:40'''

The sourceforge page doesnt show any files at present. Can you repair this please?