FF - 2009-02-18 - This widget is a canvas specialized for dataflow [L1 ] 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.

[L2 ]

Source code:


svn co

or browse online:

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:

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 (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 [L3 ]) (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.

Geoffm - 2009-08-25 07:16:40

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

LV - 2009-08-25 15:19:52

When I visit the web page, I see files. Which link are you using that does not display files?