[Tile-dev] Progress bars

[Joe E. <jen...@fl...>]

We've had a progress bar widget for a while now,
but it's lacking documentation and is missing a few
features.  Some things I can think of that it needs:


+ An "indeterminate" (aka "barber-pole") mode.  Currently
  only the "determinate" (aka "thermometer") mode is supported.

  Note that "barber-pole" mode doesn't always look like
  a barber pole; Windows and GTK+ display a rectangle that
  bounces back and forth instead.

+ Linked -variables.  The current implementation has a
  -variable option, but it goes in the wrong direction --
  setting the progress bar updates the -variable, but
  setting the variable doesn't change the widget value.

+ Animation.  On Aqua and on some KDE themes (depending on
  the user's preferred eye candy level) thermometer-style
  progress bars have an additional pulsing/throbbing effect,
  presumably to let the user know that the program hasn't
  locked up even if the bar isn't otherwise moving.
  Michael Kirkham (muonics) has a patch that implements this
  on OSX.

Anyway, I've put up another strawmanpage describing a
possible interface:

    <URL: http://tktable.sourceforge.net/tile/doc/progress.html >

Questions: Are the 'set' and 'get' methods really needed?
They're equivalent to [$w configure -value] and [$w cget -value],
respectively; or you can just access the linked -variable.

And if so, would a 'step' method be useful for indeterminate
progress bars, where [$w step] is equivalent to:

    $w configure -value [expr {[$w cget -value] + [$w cget -stepsize]}]

or

    incr $linkedVariable $stepSize


Anything else missing?

The current implementation also has -font, -foreground,
and -showvalue options (which don't do anything at the moment);
and -command and -width options, which I don't think are
needed either -- -width should be taken from the style,
and -command isn't really useful for output-only widgets
like this one.


--Joe English

  jen...@fl...