pack .this .that -expand true -fill both

Why are there two different options expand and fill? Are they both needed?

expand causes a widget to expand to fill the space available as a window is stretched, and fill causes a widget to be filled to the cell so that it lines up with other widgets.

In order to show you the difference graphically, I wrote this demonstration program:

button .this -text "this" -command exit
button .that -text "Something unthis" -command exit
 
if {$argv == 1} {
  pack .this .that
  puts stderr "Neither fill nor expand"
  # small buttons in one side of window
} elseif {$argv == 2} {
  pack .this .that -fill both
  puts stderr "No expand but with fill"
  # button widths match
} elseif {$argv == 3} {
  pack .this .that -expand true
  puts stderr "No fill but with expand"
  # buttons distributed through window
} elseif {$argv == 4} {
  pack .this .that -expand true -fill both
  puts stderr "Both fill and expand"
  # buttons expanded to truely fill window
} else {
  puts stderr "Usage: $argv0 \[1|2|3|4\]"
  exit
}

Neither, and just "expand" ...



"fill", and both ...

(written 2007-12-13)

 T218 - Tcl/Tk - Geometry Managers
  [212] Tcl/Tk (wish) Grid layout example - (2005-02-12)
  [445] Sticky news - (2005-09-15)
  [787] Tk - laying out your GUI with frames, pack and grid - (2006-06-30)
  [1335] Expanding a grid - Tcl/Tk - (2007-09-07)
  [1340] Tk locks up - 100% c.p.u. on a simple program (Tcl, Perl, Python) - (2007-09-09)

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