# Toggle Widget

    Application Header file     <Xaw/Toggle.h>
    Class Header file     <Xaw/ToggleP.h>
    Class          toggleWidgetClass
    Class Name     Toggle
    Superclass      Command

The Toggle widget is an area, often rectangular, that displays a graphic. The graphic may be a text string containing multiple lines of characters in an 8 bit or 16 bit character set (to be displayed with a font), or in a multi-byte encoding (for use with a fontset). The graphic may also be a bitmap or pixmap.

This widget maintains a Boolean state (e.g. True/False or On/Off) and changes state whenever it is selected. When the pointer is on the Toggle widget, the Toggle widget may become highlighted by drawing a rectangle around its perimeter. This highlighting indicates that the Toggle widget is ready for selection. When pointer button 1 is pressed and released, the Toggle widget indicates that it has changed state by reversing its foreground and background colors, and its `notify` action is invoked, calling all functions on its callback list. If the pointer is moved off of the widget before the pointer button is released, the Toggle widget reverts to its previous foreground and background colors, and releasing the pointer button has no effect. This behavior allows the user to cancel the operation.

Toggle widgets may also be part of a radio group. A radio group is a list of at least two Toggle widgets in which no more than one Toggle may be set at any time. A radio group is identified by the widget ID of any one of its members. The convenience routine XawToggleGetCurrent will return information about the Toggle widget in the radio group.

Toggle widget state is preserved across changes in sensitivity.

## Resources

When creating a Toggle widget instance, the following resources are retrieved from the argument list or from the resource database:

Name | Class | Type | Notes | Default Value
accelerators | Accelerators | AcceleratorTable |  | NULL
ancestorSensitive | AncestorSensitive | Boolean | D | True
background | Background | Pixel |  | XtDefaultBackground
backgroundPixmap | Pixmap | Pixmap |  | XtUnspecifiedPixmap
bitmap | Bitmap | Pixmap |  | None
borderColor | BorderColor | Pixel |  | XtDefaultForeground
borderPixmap | Pixmap | Pixmap |  | XtUnspecifiedPixmap
borderWidth | BorderWidth | Dimension |  | 1
callback | Callback | XtCallbackList |  | NULL
colormap | Colormap | Colormap |  | Parent's Colormap
cornerRoundPercent | CornerRoundPercent | Dimension |  | 25
cursor | Cursor | Cursor |  | None
cursorName | Cursor | String |  | NULL
depth | Depth | int | C | Parent's Depth
destroyCallback | Callback | XtCallbackList |  | NULL
encoding | Encoding | UnsignedChar |  | XawTextEncoding8bit
font | Font | XFontStruct |  | XtDefaultFont
fontSet | FontSet | XFontSet |  | XtDefaultFontSet
foreground | Foreground | Pixel |  | XtDefaultForeground
height | Height | Dimension | A | graphic height + 2 * `internalHeight`
highlightThickness | Thickness | Dimension | A | 2 (0 if Shaped)
insensitiveBorder | Insensitive | Pixmap |  | GreyPixmap
internalHeight | Height | Dimension |  | 2
internalWidth | Width | Dimension |  | 4
international | International | Boolean | C | False
justify | Justify | Justify |  | XtJustifyCenter (center)
label | Label | String |  | name of widget
leftBitmap | LeftBitmap | Bitmap |  | None
mappedWhenManaged | MappedWhenManaged | Boolean |  | True
pointerColor | Foreground | Pixel |  | XtDefaultForeground
pointerColorBackground | Background | Pixel |  | XtDefaultBackground
radioData | RadioData | Pointer |  | Name of widget
radioGroup | Widget | Widget |  | No radio group
resize | Resize | Boolean |  | True
screen | Screen | Screen | R | Parent's Screen
sensitive | Sensitive | Boolean |  | True
shapeStype | ShapeStyle | ShapeStyle |  | Rectangle
state | State | Boolean |  | Off
translations | Translations | TranslationTable |  | See below
width | Width | Dimension | A | graphic width + 2 * `internalWidth`
x | Position | Position |  | 0
y | Position | Position |  | 0

`radioData`

- Specifies the data that will be returned by XawToggleGetCurrent when this is the currently set widget in the radio group. This value is also used to identify the Toggle that will be set by a call to XawToggleSetCurrent. The value NULL will be returned by XawToggleGetCurrent if no widget in a radio group is currently set. Programmers must not specify NULL (or Zero) as `radioData`.

`radioGroup`

- Specifies another Toggle widget that is in the radio group to which this Toggle widget should be added. A radio group is a group of at least two Toggle widgets, only one of which may be set at a time. If this value is NULL (the default) then the Toggle will not be part of any radio group and can change state without affecting any other Toggle widgets. If the widget specified in this resource is not already in a radio group then a new radio group will be created containing these two Toggle widgets. No Toggle widget can be in multiple radio groups. The behavior of a radio group of one toggle is undefined. A converter is registered which will convert widget names to widgets without caching.

`state`

- Specifies whether the Toggle widget is set (`True`) or unset (`False`).

## Toggle Actions

The Toggle widget supports the following actions:

- Switching the Toggle widget between the foreground and background colors with `set` and `unset` and `toggle`

- Processing application callbacks with `notify`

- Switching the internal border between highlighted and unhighlighted states with `highlight` and `unhighlight`

The following are the default translation bindings used by the Toggle widget:

         <EnterWindow>:     highlight(Always)
         <LeaveWindow>:     unhighlight()
         <Btn1Down>,<Btn1Up>:     toggle() notify()

## Toggle Actions

The full list of actions supported by Toggle is:

`highlight`(condition)

- Displays the internal highlight border in the color (`foreground` or `background` ) that contrasts with the interior color of the Toggle widget. The conditions `WhenUnset` and `Always` are understood by this action procedure. If no argument is passed then `WhenUnset` is assumed.

`unhighlight`()

- Displays the internal highlight border in the color (`foreground` or `background` ) that matches the interior color of the Toggle widget.

`set`()

- Enters the set state, in which `notify` is possible. This action causes the Toggle widget to display its interior in the `foreground` color. The label or bitmap is displayed in the `background` color.

`unset`()

- Cancels the set state and displays the interior of the Toggle widget in the `background` color. The label or bitmap is displayed in the `foreground` color.

`toggle`()

- Changes the current state of the Toggle widget, causing to be set if it was previously unset, and unset if it was previously set. If the widget is to be set, and is in a radio group then this procedure may unset another Toggle widget causing all routines on its callback list to be invoked. The callback routines for the Toggle that is to be unset will be called before the one that is to be set.

`reset`()

- Cancels any `set` or `highlight` and displays the interior of the Toggle widget in the `background` color, with the label displayed in the `foreground` color.

`notify`()

- When the Toggle widget is in the `set` state this action calls all functions in the callback list named by the `callback` resource. The value of the call_data argument in these callback functions is undefined.

When a bitmap of depth greater that one (1) is specified the set(), unset(), and reset() actions have no effect, since there are no foreground and background colors used in a multi-plane pixmap.

## Radio Groups

There are typically two types of radio groups desired by applications. The default translations for the Toggle widget implement a "zero or one
of many" radio group. This means that there may be no more than one Toggle widget active, but there need not be any Toggle widgets active.

The other type of radio group is "one of many" and has the more strict policy that there will always be exactly one radio button active. Toggle widgets can be used to provide this interface with a slight modification to the translation table of each Toggle in the group.

         <EnterWindow>:     highlight(Always)
         <LeaveWindow>:     unhighlight()
         <Btn1Down>,<Btn1Up>:     set() notify()

This translation table will not allow any Toggle to be unset except as a result of another Toggle becoming set. It is the application programmer's responsibility to choose an initial state for the radio group by setting the `state` resource of one of its member widgets to `True`.

## Convenience Routines

The following functions allow easy access to the Toggle widget's radio group functionality.

### Changing the Toggle's Radio Group.

To enable an application to change the Toggle's radio group, add the Toggle to a radio group, or remove the Toggle from a radio group, use XawToggleChangeRadioGroup.

      void XawToggleChangeRadioGroup
      Widgetw, radio_group

w

- Specifies the Toggle widget.

radio_group

- Specifies any Toggle in the new radio group. If NULL then the Toggle will be removed from any radio group of which it is a member.

If a Toggle is already set in the new radio group, and the Toggle to be added is also set then the previously set Toggle in the radio group is unset and its callback procedures are invoked. Finding the Currently selected Toggle in a radio group of Toggles

To find the currently selected Toggle in a radio group of Toggle widgets use XawToggleGetCurrent.

      XtPointer XawToggleGetCurrent
      XtPointer XawToggleGetCurrent(radio_group)
      Widget radio_group

radio_group

- Specifies any Toggle widget in the radio group.

The value returned by this function is the `radioData` of the Toggle in this radio group that is currently set. The default value for `radioData` is the name of that Toggle widget. If no Toggle is set in the radio group specified then NULL is returned. Changing the Toggle that is set in a radio group.

To change the Toggle that is currently set in a radio group use XawToggleSetCurrent.

      void XawToggleSetCurrent
      voidXawToggleSetCurrent(radio_group, radio_data)
      Widget radio_group
      XtPointer radio_data

radio_group

- Specifies any Toggle widget in the radio group.

radio_data

- Specifies the `radioData` identifying the Toggle that should be set in the radio group specified by the radio_group argument.

XawToggleSetCurrent locates the Toggle widget to be set by matching radio_data against the `radioData` for each Toggle in the radio group. If none match, XawToggleSetCurrent returns without making any changes. If more than one Toggle matches, XawToggleSetCurrent will choose a Toggle to set arbitrarily. If this causes any Toggle widgets to change state, all routines in their callback lists will be invoked. The callback routines for a Toggle that is to be unset will be called before the one that is to be set. Unsetting all Toggles in a radio group.

To unset all Toggle widgets in a radio group use XawToggleUnsetCurrent.

      void XawToggleUnsetCurrent
      void XawToggleUnsetCurrent(radio_group)
      Widget radio_group

radio_group

- Specifies any Toggle widget in the radio group.

If this causes a Toggle widget to change state, all routines on its callback list will be invoked.