Write a New Custom Widget

Steps and examples for writing a custom widget using the toolkit.

  1. Create a class.
    1. Create XYZentry inheriting from hwtk::interface::HWIWidget 
      itcl::class XYZentry {
    inherit hwtk::interface::HWIWidget;

    itk_option define -orient orient Orient "horizontal";

    constructor {args} {};
    destructor} {};

    public method get {args};
}
  2. Writing the constructor: 
    itcl::body XYZentry:constructor {args} {
    itk_component add hull {ttk::frame $itk_interior } { }
    itk_component add x {hwtk::label $itk_interior.__x -text "X:"} { }
    itk_component add xe {hwtk::entry $itk_interior.__xe -inputtype double} { }
    itk_component add y {hwtk::label $itk_interior.__y -text "Y:"} { }
    itk_component add ye {hwtk::entry $itk_interior.__ye -inputtype double} { }
    itk_component add z {hwtk::label $itk_interior.__z -text "Z:"
    itk_component add ze {hwtk::entry $itk_interior.__ze -inputtype double

hwtk_setdefaultbindings;
eval itk_initialize ;
}
  3. Writing the Option Config body: 
    itcl::configbody XYZentry::orient {
     switch -glob --itck_option(-orient)
          h* {
               pack configure $itk_component(x) $itk_component(xe) -side left
               pack configure $itk_component(y) $itk_component(ye) -side left
               pack configure $itk_component(z) $itk_component(ze) -side left
          )
          v* {
               pack configure $itk_component(x) $itk_component(xe) -side top
               pack configure $itk_component(y) $itk_component(ye) -side top
               pack configure $itk_component(z) $itk_component(ze) -side top
          )
     }
}
  4. Writing with the Public method (get) 
    itcl::body XYZentry::get {args} {
     if {[llength [info level 0]]} {
          return [list [ $itk_component(xe) [$itk_component(ye) [$itk_component(ze) ]
     }
     if {[llength [info level 0]]> 2} {
          return -code error "wrong args # should be $itk_component (hull) get ?X? ?Y? ?Z?"
     }
     switch -- $args{
          X {return [$itk_component(xe) get]}
          Y {return [$itk_component(ye) get]}
          Z {return [$itk_component(ze) get]}
     }
}
Simple custom widget
toplevel .t
pack [XYZentry .t.e]
Accessing the public method
% .t.e get X
12.323
% .t.e get Y
22.333
% .t.e get Z
45.123
% .t.e get
12.323 22.333 45.123