Mastering Perl/Tk

Text Manipulation

You can alter the appearance and location of the text within the Button. The simplest way is to use the -font option to change the font. Chapter 3 covers fonts in detail so we’ll just look at a few simple ways to change the font:

-font => "{Times New Roman} 12 {normal}"

There can be only a single font for each Button, so the text string cannot change font in the middle of a word. However, each Button (or widget) in an application can have a different font. Here is an example of two Buttons in a window, one with the default font and the other with "lucidasans-14" (a Unix font) as its font:

$mw->Button(-text => "Exit", 
            -command => sub { exit })->pack(-side => 'left', 
                                      -fill => 'both', -expand => 1);
$mw->Button(-text => "Exit", 
            -font => "lucidasans-14",
            -command => sub { exit })->pack(-side => 'left', 
                                      -fill => 'both', -expand => 1);

Figure 4-16 shows the resulting window.

Figure 4-16. Buttons with various fonts

You can also move the text around within the Button. As in a word-processing document, you can change where the text will justify. The option that controls this is -justify:

-justify => 'left' | 'right' | 'center'

The default for -justify is 'center'. Normally the text displayed in a Button is a quick one- or two-word statement; for example, Exit, Done, Yes, No, or Cancel. The justification of the text isn’t too obvious unless multiple lines of text are used. ...