8.5 SCIRun GUI Description

A module GUI allows access to ITK filter parameters. By default, a GUI is created that associates a text entry widget with each filter parameter. By writing a GUI description file, the user can replace all or part of the default GUI.

SCIRun GUI description files are located in directory:

  SCIRun/src/Packages/Insight/Dataflow/Modules/Filters/XML

SCIRun GUI filter description files follow the naming convention:

  gui_filter_name.xml

for example:

  gui_BinaryThresholdImageFilter.xml

The structure of the GUI description file consists of the top-level element <filter-gui> that encloses one or more <param> elements. Each <param> element associates a filter parameter with a GUI widget:

  <?xml version="1.0"  encoding="iso-8859-1"?>
  <!DOCTYPE filter-gui SYSTEM "gui_filter.dtd">
  <filter-gui name="name">
    <param name="parameter_name">
      <widget_element>
      ⋮
      </widget_element>
      ⋮
    </param>
    ⋮  
  </filter-gui>

The value of a <param> element's name attribute must match the value of the corresponding <name> element in the filter description file (see Element <parameters>)

One or more widgets can be specified in any order. Widgets are displayed top to bottom in the GUI window in the order specified in the ITK filter description file. Note that a text entry widget is generated for each parameter lacking a <param> element.

Widget_element is one of text-entry, checkbutton, scrollbar, radiobutton, or const. Notice that each widget_element, except <const>, must contain a <default> element.

A text entry widget allows the user to enter an arbitrary string of text, and is given an initial (default) value:

  <text-entry>
    <default>default_string</default>
  </text-entry>

A check button widget allows the user to select between true and false values. A check button widget is given a default value of 0 (false) or 1 (true):

  <checkbutton>
    <default>0_or_1</default>
  </checkbutton>

A scrollbar widget allows the user to select one value from a range of values. A scrollbar widget is given a min value, a max value, an optional scroll step value, and an initial value:

  <scrollbar>
    <min>min_value</min>
    <max>max_value</max>
    <step>step_value</step>
    <default>default_value</default>
  </scrollbar>

If the <step> element is not present, the scroll step value defaults to 1.

A radiobutton is a set of button widgets that allow the user to select one value from a set of values. Each value in a set is represented by a button widget. Each button has a label and a value. A <default> element provides <radiobutton>'s initial value. The initial value must be a value specified in a <button> element:

  <radiobutton>
    <button>
      <label>label_string</label>
      <value>value</value>
    </button>
    ⋮  
    <default>initial_value</default>
  </radiobutton>

A ITK filter parameter may be set to a constant value using element <const>. No GUI widget will be generated for a constant parameter and the user cannot change the value of the parameter.

  <const value="initial_value"</const>