Advanced Perl Programming

Widget Tour

This section provides an introduction to most of the interesting widget classes implemented in Tk and Tix and exercises their commonly used configuration options and methods. To reduce clutter and to allow quick lookups later on (when you know what you are looking for), this extensive set of properties and methods is provided as a separate appendix: Appendix B. Be aware that this chapter, extensive as it is, is only a subset (though a significant subset) of the entire Tk widget feature set. It also does not cover all widgets provided by Tk and Tix. Perl/Tk comes with the entire original well-written and comprehensive Tk documentation.

Widget Properties

Please skim Table 1.1 to get an idea of the kind of configurable properties that all widgets share. Most of these properties are ordinary strings or numbers, but three types of properties are worth delving into some detail before we proceed to discussing the actual widgets: fonts, images, and colors.

Fonts

Font values are specified in the XLFD format (X Logical Font Description), which consists of 14 fields separated by hyphens, as shown in Figure 14.2.

Figure 14-2. Fields in a font

Fortunately, we don’t have to remember the purpose of most of these fields. Any of these fields can have the wildcard “*” or “?”, but it is important to get the number of hyphens right. On the X Windows system, there are two utilities, a graphical ...