The Toggle Widget
Author: Roland Krause 2002, roland_krause@freenet.de
Description: Documentation to XawPlus

### _________________________________________________________XawPlus

### The Toggle Widget

Application Header file Class Header file Class Class Name Superclass | <X11/XawPlus/Toggle.h> <X11/XawPlus/ToggleP.h> toggleWidgetClass Toggle Command

The Toggle widget is an rectangular area, containing a text label or bitmap image. 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, its shape may become highlighted. This highlighting indicates that the toggle is now ready for selection. When pointer button 1 is pressed and released, the Toggle widget indicates that it has changed state by displaying itself as a sunken button and its notify action is invoked, calling all functions on its callback list. If the pointer is moved out of the widget before the toggle is released, the widget display itself as an unpressed button and releasing the button has no effect. This behavior allows the user to cancel an action.

Toggle buttons may also be part of a radio group. A radio group is a list of at least two Toggle buttons 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 button in the radio group. Toggle widget state is preserved across changes in sensitivity.

### Differences between Xaw and XawPlus

Since the 3D extensions of Simple are inserted, the Toggle widget has the additional resources highlightColor, shadowColor and buttonBorderWidth. The default background color is now grey75. These three colors and the width of the button border are used to draw the shape of a button with the inherited methods of the Simple widget class. Since XawPlus only supply rectangular buttons, the resources shapeStyle and cornerRoundPercent has no meaning.

The bitmap and leftBitmap resources now also provide support of XPM styled pixmaps. These resources are inherited from the Label widget class. Look there for a description of this new feature.

Toggle provides tooltips. If a help text and useHelp is set in the resources, a help window is popped up afer 1.2 seconds when the mouse pointer stay over the widgets window. This feature is inherited from the Command widget class.

### Resources

When creating a Toggle widget instance, the following resources are retrieved from the argument list of XtSetValues() or XtVaSetValues() or from the resource database:

Name | Class | Type | Default Value
OBJECT: |  |  |
destroyCallback | Callback | Pointer | NULL
RECTANGLE: |  |  |
borderWidth height sensitive width x y | BorderWidth Height Sensitive Width Position Position | Dimension Dimension Boolean Dimension Position Position | 0 12 True 12 0 0
CORE: |  |  |
border background mappedWhenManaged | BorderColor Background MappedWhenManaged | Pixel Pixel Boolean | XtDefaultForeground grey75 True
SIMPLE: |  |  |
cursor cursorName pointerColor pointerColorBackground insensitiveBorder international highlightColor shadowColor buttonBorderWidth | Cursor Cursor Foreground Background Insensitive International Background Background Width | Cursor String Pixel Pixel Pixmap Boolean Pixel Pixel Dimension | None NULL XtDefaultForeground XtDefaultBackground NULL False grey90 grey40 2
LABEL: |  |  |
font fontset encoding foreground internalHeight internalWidth justify resize truncateLabel truncLeftSide label leftBitmap leftClipMask bitmap clipMask | Font FontSet Encoding Foreground Height Width Justify Resize Truncate Truncate Label LeftBitmap LeftBitmap Pixmap Pixmap | XFontStruct* FontSet unsigned char Pixel Dimension Dimension XtJustify Boolean Boolean Boolean String Bitmap ClipMask Bitmap ClipMask | XtDefaultFont XtDefaultFontSet XawTextEncoding8bit XtDefaultForeground 2 4 XtJustifyCenter True True False NULL None None None None
COMMAND: |  |  |
helpText helpBackground useHelp highlightThickness highlightMode callback translations accelerators ancestorSensitive | Label Background Boolean Thickness Boolean Callback Translations Accelerators AncestorSensitive | String Pixel Boolean Dimension Boolean XtCallbackList TranslationTable AcceleratorTable Boolean | NULL LightGoldenrodYellow True 2 True NULL see doc or source NULL True
TOGGLE: |  |  |
radioGroup radioData state | RadioGroup RadioData State | Widget Pointer Boolean | NULL *) (caddr_t)Widget **) Off

*) | To use the toggle as a radio toggle button, set this resource to point to any other widget in the radio group.
**) | This is the data returned from a call to XtToggleGetCurrent, by default this is set to the name of toggle widget.

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 button between raised or sunken shape with set, unset and toggle.
- Processing application callbacks with notify
- Switching between highlighted and unhighlighted states with highlight and unhighlight.

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

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

The full list of actions supported by Toggle is:

highlight() | Displays the interior of the toggle in the raised button style, if highlightMode is set to True. If not, the toggle is always displayed in the raised button style. In this case highlight() has no meaning. Since XawPlus 2.0 the conditions WhenUnset and Always are not longer supported.
unhighlight() | Displays a flat border if highlightMode is set to True. If not, the toggle is displayed in the raised style. In this case unhighlight() has no meaning.
set() | Enters the set state, in which notify is possible. This action causes the toggle to display its interior in the sunken style.
unset() | Cancels the set state and displays the interior as a raised button.
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 in the flat style if highlightMode is set to True. If not, the toggle is displayed in the raised style.
notify() | When the button 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.

In contrast to Xaw with XawPlus the set(), unset(), and reset() actions have the same effect with a multi-plane XPM 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 button active, but there need not be any buttons 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> <LeaveWindow> <Btn1Down>, <Btn1Up> | highlight() unhighlight() 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.

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(w, radio_group)
> Widget w, 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.

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

To change the Toggle that is currently set in a radio group use XawToggleSetCurrent():

> void XawToggleSetCurrent(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.

To unset all Toggle widgets in a radio group use 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.

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