5 checkbox

The checkbox is a type of button with the activation states on and off. A particular visual representation is linked to each of these states, so that the checkbox state is recognizable at any time. A filled square represents the on state, an empty square represents the off state.

Definition

{ export | reexport } { model } checkbox { <Identifier> }
{
  <standard attributes>
  <plain attributes>
  <hierarchy attributes>
  <layout attributes>
  <text attributes>
  <object-specific attributes>
}

Important note on tab navigation

Checkboxes are assigned to Tab groups by the window systems. The group is mostly determined by the parent object. Single checkboxes can be reached individually with the Tab key. For checkboxes within a group, only one group element can be reached via the Tab key. The cursor keys are used to navigate within the group.
The .navigation attribute can be used to influence the Tab navigation. It determines whether a checkbox in the Tab navigation belongs to a group of elements or is treated as a stand-alone element.

Events

Children

Parent

5.1 attributes

5.2 Specific attributes

attribute	Description
.active	Defines at .style = checkbox (2) whether the object should have the state on (true) or off (false). See chapter “Checkbox as a tristate button”
.height	Height of the object. At value 0 the IDM calculates the height automatically based on the current character set.
.navigation	Determines whether a checkbox belongs to a group of elements or is treated as a stand-alone element in the `Tab` navigation. Stand-alone checkboxes can be reached individually with the `Tab` key. For checkboxes within a group, only one group element can be reached by `Tab` key. The cursor keys are used to navigate within the group. navi_default (default) navi_grouped navi_tab
options[enum]	Options of the object. Indices: opt_use_widget (only Motif) opt_push_like (only Microsoft Windows) opt_center_toolhelp (only Microsoft Windows)
.state	Current activation state of the object. Possible values: state_unchecked state_checked state_indeterminate See chapter “Checkbox as a tristate button”
style	Sets the appearance and behavior of the object. Possible values: checkbox (2, default) tristate (3) See chapter “Checkbox as a tristate button”
.text	Displayed text (caption).
.width	Width of the object. At value 0 the IDM calculates the width automatically based on the current character set.

5.3 Checkbox as a tristate button

Checkbox and Tristatebutton are implemented in ISA Dialog Manager using the same object. The .style attribute controls what type of object is displayed. The representation of the tristate button depends on the corresponding window system.

The states of the checkbox (as a tristate button) can be queried and set via the .state attribute.

For a tristate button, the .active attribute always returns false. Therefore, it is not suitable for querying the state of the checkbox. This does not change even if the checkbox is dynamically changed from .style = tristate (3) to .style = checkbox (2) at runtime.

The activate and deactivate events are not available for a tristate button.

Whether the interactive selection of the tristate button switches between all three states or only between on (state_checked) and off (state_unchecked), as well as the sequence when switching between the three states, is defined by the respective window system. The IDM has no influence on this.

5.4 Note for checkbox for Microsoft Windows

Concerning the background color, please refer to the notes on attribute .bgc in the “Attribute Reference”.

5.5 Example

Four navigable checkboxes within one window. The first two within a group:

window MAIN
{
  /* tab navigation via grouping.
   * within the group each checkbox
   * can be reached using cursor keys */
  groupbox 
  {
    .xleft 10;    
    child checkbox Bold
    {
      .ytop 10;
      .text "bold";
      .visible true;
      .active false;
    }
 
    child checkbox Underline
    {
      .ytop 40;
      .text "underline";
      .visible true;
      .active true;
    }
  }

  /* tab navigation via .navigation. 
   * each checkbox can be reached 
   * individually using Tab key */
  child checkbox Italic
  {
    .xleft 10;
    .ytop 70;
    .text "italic";
    .visible true;
    .active true;
    .navigation navi_tab;
  }
 
  child checkbox Shadow
  {
    .xleft 10;
    .ytop 100;
    .text "shadow";
    .visible true;
    .active false;
    .navigation navi_tab;
  }
}

Figure 13-2: Checkbox