Sometimes I'm responsible for maintenance of an application that includes such elements as
pack [button .b1 -text Lion -width 10] [button .b2 -text Hippopotamus -width 10]
[show picture here] Notice that there's a problem with this fragment; 'Hippopotamus' is truncated. That's not a good thing. Most immediately, it's because .b2 has been assigned a width that's too small. Generally in Tk it's OK to allow things to have default sizes; there are a couple of legitimate reasons to assign manifest sizes, though, including [... and ...--but people also mistakenly set sizes when ...].
If those widths are constant values, they need to be correct ones. Too-small labels make bad impressions on users. Here's a way I ask an application to tell me about itself: I source in
proc walker {w procedure} {
$procedure $w
foreach child [winfo children $w] {
walker $child $procedure
}
}
proc check_width w {
switch [winfo class $w] {
Button -
Label {
set original_width [$w cget -width]
set x_extent [winfo reqwidth $w]
$w configure -width 0
set needed_x_extent [winfo reqwidth $w]
set result [expr $needed_x_extent > $x_extent]
$w configure -width $original_width
return $result
}
default {
return 0
}
}
}then execute
proc c w {
if [check_width $w] {
puts "Widget '$w' isn't wide enough."
}
}
walker . cThe truth is, that's not exactly what I do, but it's close enough. For sufficiently weathered applications, and especially ones that have moved around between platforms, I usually pick up a few widgets that I'd rather find this way than by having a customer complain.