 
 subsection3_4_3.html  subsection3_4_2.html  subsection3_4_2.html  tableofcontents3_1.html   Next: subsection3_4_3.html Writing Methods Up: subsection3_4_2.html Widget Class Declaration  Previous: subsection3_4_2.html Widget Class Declaration    Using the tixWidgetClass Command 
We can use the 
tixWidgetClass command to declare a new
class. The syntax is:
tixWidgetClass classCommandName {
    -switch value
    -switch value
    ....
}
For example, the following is the declaration section of 
TixArrowButton:
tixWidgetClass tixArrowButton {
    -classname  TixArrowButton
    -superclass tixPrimitive
    -method {
        flash invoke invert
    }
    -flag {
        -direction -state
    }
    -configspec {
        {-direction direction Direction e}
        {-state state State normal}
    }
    -alias {
        {-dir -direction}
    }
    -default {
        {*Button.anchor         c}
        {*Button.padX           5}
    }
}
We'll look at what each option means as the command is described in the
following sections. The first argument for 
tixWidgetClass is the
command name for the widget class (
tixArrowButton). Command names are
used to create widgets of this class. For example, the code:
tixArrowButton .arrow
creates a widget instance 
.arrow of the class TixArrowButton.
 Also, the command name is used as a prefix of all the methods of this
class. For example, the 
Foo and Bar methods of the class
TixArrowButton will be written as tixArrowButton:Foo and
tixArrowButton:Bar.
The class name of the class (
TixArrowButton) is specified by the
-classname switch inside the main body of the declaration. The class
name is used only to specify options in the TK option database.
Notice the difference in the capitalization of the class name and the
command name of the 
TixArrowButton class: both of them have the
individual words capitalized, but the command name
(
tixArrowButton) starts with a lower case letter while the class name
(
TixArrowButton) starts with an upper case letter. When you create
your own classes, you should follow this naming convention.
The 
-superclass switch specifies the superclass of the new widget. In
our example, we have set it to 
tixPrimitive.
http://tix.sourceforge.nethttp://tix.sourceforge.net 