Mastering Perl/Tk

Changing the Size of a Button

Normally the size of the Button is automatically determined by the application and is dependent on the text string or image displayed in the Button. The width and height can be specified explicitly by using the -width and -height options:

-width => x, -height => y

The values specified for x and y vary depending on whether a bitmap/image or text is displayed in the Button. When a bitmap or image is displayed, the values in x and y represent valid screen distances. If text is displayed on the Button, x and y are character sizes.

This example shows one Button that is the default size and another drawn with -width of 10 and -height of 10. (It is not necessary that the amounts for -width and -height be the same or that you use both options.)

$mw->Button(-text => "Exit", 
            -command => sub { exit })->pack(-side => 'left');
$mw->Button(-text => "Exit", 
            -width => 10, -height => 10,
            -command => sub { exit })->pack(-side => 'left');

In Figure 4-28, which illustrates this example, the second Button is much taller than it is wide, because text characters are taller than they are wide.

Figure 4-28. Default -width and -height (left) versus Button with -width and -height set (right)

The values specified for both -width and -height are characters, because the Button is displaying text. When -width and -height are used with a bitmap, the amount specified is in screen distance. ...