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15.16. Responding to Tk Resize EventsProblemYou've written a Tk program, but your widget layout goes awry when the user resizes their window. SolutionYou can prevent the user from resizing the window by intercepting the Configure event: use Tk; $main = MainWindow->new(); $main->bind('<Configure>' => sub { $xe = $main->XEvent; $main->maxsize($xe->w, $xe->h); $main->minsize($xe->w, $xe->h); }); Or you can use $widget->pack( -fill => "both", -expand => 1 ); $widget->pack( -fill => "x", -expand => 1 ); DiscussionBy default, packed widgets resize if their container changes size - they don't scale themselves or their contents to the new size. This can lead to empty space between widgets, or cropped or cramped widgets if the user resizes the window. One solution is to prevent resizing. We You often want to let the user resize the application's windows. You must then define how each widget will react. Do this through the arguments to the The solution requires both options. Without Different parts of your application will behave differently. The main area of a web browser, for example, should probably change size in both dimensions when the window is resized. You'd pack the widget like this: $mainarea->pack( -fill => "both", -expand => 1); The menubar above the main area, though, should expand horizontally but not vertically. You'd pack the widget thus: $menubar->pack( -fill => "x", -expand => 1 ); Associated with resizing is the need to anchor a widget to part of its container. Here's how you'd anchor the menubar to the top left corner of its container when you call $menubar->pack (-fill => "x", -expand => 1, -anchor => "nw" ); Now when you resize it, the menubar stays at the top of the window where it belongs, instead of being centered in wide open space. See AlsoThe pack (n), XEvent (3), and XConfigureEvent (3) manpages (if you have them); Tcl and the Tk Toolkit, by John Ousterhout, Addison-Wesley (1994) |