Pre-requisites: you should be familiar with Tk widgets and programming, or read the Tk book along with this book
Before delving into the deep philosophy of the Tix widgets, let us first have a quick example to demonstrate the usefulness and convenience of an Tix widget: the TixControl is basically an entry widget that displays a value. Next to the entry, there are two up and down arrow buttons for you to adjust the value inside the entry widget.