Version 38 of Keep a GUI alive during a long calculation

sillymonkeysoftware - 2011-02-12 16:42:49

Hi Folks,

I'm having a bit of difficulty implementing the simple GUI keep-alive as described above. My program needs to calculate and export large chunks of audio data. If I do it in a while-loop I get a frozen gui and spinning beach ball (Mac) until everything completes. Really not what I want the users to suffer through, and there's no way to halt it once it's begun.

I was thrilled when I found the examples above. So here's what I initially tried, but it seems to only export one iteration of the loop, then returns:

    proc export_loop {} {
        set ::gExportStatus [continue_export]
        if {$::gExportStatus > 0} {
            after idle [list after 0 export_loop]
        }
        return
    }

    export_loop

So, after numerous attempts to get the above working, I'm now using this:

    set ::gExportStatus 1

    while {$::gExportStatus > 0} {
        update idletasks
        after idle [dict get $gInterface progress_bar] configure -value $::gExportStatus
        set ::gExportStatus [continue_export]
    }

` which seems, well... hideous. and is only slightly better than the spinning beach ball frozen gui. There's still no way to actually catch a halt from a button press and stop the export.

Now, continue_export is acutally a C function that returns:

The number of frames that were exported.
A zero if all frames have exported and there is nothing left to do.
A negative number if there was an error during export.

Is the problem that I'm throwing the call to the C function in the middle of the proc? Any thoughts?