CascadeButton links two MenuPanes or a MenuBar to a MenuPane.
It is used in menu systems and must have a RowColumn parent
with its XmNrowColumnType resource set to XmMENU_BAR,
XmMENU_POPUP or XmMENU_PULLDOWN.
It is the only widget that can have a Pulldown MenuPane attached to it as
a submenu. The submenu is displayed when this widget is activated within
a MenuBar, a PopupMenu, or a PulldownMenu. Its visuals can
include a label or pixmap and a cascading indicator when it is in a
Popup or Pulldown MenuPane; or, it can include only a label or a pixmap
when it is in a MenuBar.
The default behavior associated with a CascadeButton depends on the type
of menu system in which it resides.
By default, BSelect controls the behavior of the CascadeButton.
In addition, BMenu controls the behavior of the CascadeButton if
it resides in a PopupMenu system.
The actual mouse button used is determined by its RowColumn parent.
A CascadeButton's visuals differ from most other button gadgets. When the
button
becomes armed, its visuals change from a 2-D to a 3-D look, and it displays
the submenu that has been attached
to it. If no submenu is attached, it simply changes its visuals.
When a CascadeButton within a Pulldown or Popup MenuPane
is armed as the result of the user
moving the mouse pointer into the widget, it does not immediately display its
submenu. Instead, it waits a short amount of time to see if the arming
was temporary (that is, the user was simply passing through the widget), or
whether the user really wanted the submenu posted. This time delay is
configurable via XmNmappingDelay.
CascadeButton provides a single mechanism for
activating the widget from the keyboard. This mechanism is referred to as
a keyboard mnemonic.
If a mnemonic has been
specified for the widget, the user may activate the CascadeButton
by simply typing the mnemonic while the CascadeButton is visible.
If the CascadeButton is in a MenuBar and the MenuBar does not have the
focus, the MAlt modifier must be
pressed with the mnemonic.
Mnemonics are typically used to interact with a menu
via the keyboard interface.
If in a Pulldown or Popup MenuPane and there is a submenu attached, the
XmNmarginBottom, XmNmarginLeft, XmNmarginRight, and
XmNmarginTop resources may
enlarge to accommodate XmNcascadePixmap.
XmNmarginWidth defaults
to 6 if this
resource is in a MenuBar; otherwise, it takes Label's default, which
is 2.
Classes
CascadeButton inherits behavior and resources from Core,
XmPrimitive, and XmLabel classes.
The class pointer is xmCascadeButtonWidgetClass.
The class name is XmCascadeButton.
New resources
The following table defines a set of widget resources used by the programmer
to specify data. The programmer can also set the resource values for the
inherited classes to set attributes for this widget. To reference a
resource by name or by class in a .Xdefaults file, remove the
``XmN'' or ``XmC'' prefix and use the remaining letters.
To specify one of the defined values for a resource in a .Xdefaults
file, remove the ``Xm'' prefix and use
the remaining letters (in either lowercase or uppercase, but include any
underscores between words).
The codes in the access column indicate if the given resource can be
set at creation time (C),
set by using XtSetValues (S),
retrieved by using XtGetValues (G), or is not applicable
(N/A).
XmCascadeButton resource set
Name
Class
Type
Default
Access
XmNactivateCallback
XmCCallback
XtCallbackList
NULL
C
XmNcascadePixmap
XmCPixmap
Pixmap
dynamic
CSG
XmNcascadingCallback
XmCCallback
XtCallbackList
NULL
C
XmNmappingDelay
XmCMappingDelay
int
180 ms
CSG
XmNsubMenuId
XmCMenuWidget
Widget
NULL
CSG
XmNactivateCallback
Specifies the list of callbacks that is called
when the user activates the CascadeButton widget,
and there is no submenu attached to pop up. The activation occurs by
releasing a mouse button
or by typing the mnemonic associated with the widget. The specific mouse
button depends on information in the RowColumn parent. The reason
sent by the callback is XmCR_ACTIVATE.
XmNcascadePixmap
Specifies the cascade pixmap displayed on one end of the widget when
a CascadeButton is used within a Popup or Pulldown MenuPane and a submenu
is attached.
The Label class resources XmNmarginBottom, XmNmarginLeft,
XmNmarginRight, and XmNmarginTop may be modified to ensure
that room is left for the cascade pixmap.
The default cascade pixmap is an arrow pointing to the side of the menu
where the submenu will appear.
XmNcascadingCallback
Specifies the list of callbacks that is called
just prior to the mapping of the submenu associated with
CascadeButton. The reason sent by the callback is XmCR_CASCADING.
XmNmappingDelay
Specifies the amount of time, in milliseconds, between when a CascadeButton
becomes armed and when it maps its submenu. This delay is used only when
the widget is within a Popup or Pulldown MenuPane.
The value must not be negative.
XmNsubMenuId
Specifies the widget ID for the Pulldown MenuPane to be associated with
this CascadeButton. The specified MenuPane is displayed
when the CascadeButton becomes armed. The MenuPane must have been created
with the appropriate parentage depending on the type of menu used. See
XmCreateMenuBar(Xm),
XmCreatePulldownMenu(Xm),
and
XmCreatePopupMenu(Xm)
for more information on the menu systems.
Inherited resources
CascadeButton inherits behavior and resources from the following
superclasses. For a complete description of each resource, refer to the
man page for that superclass.
XmLabel resource set
Name
Class
Type
Default
Access
XmNaccelerator
XmCAccelerator
String
NULL
N/A
XmNacceleratorText
XmCAcceleratorText
XmString
NULL
N/A
XmNalignment
XmCAlignment
unsigned char
dynamic
CSG
XmNfontList
XmCFontList
XmFontList
dynamic
CSG
XmNlabelInsensitivePixmap
XmCLabelInsensitivePixmap
Pixmap
XmUNSPECIFIED_PIXMAP
CSG
XmNlabelPixmap
XmCLabelPixmap
Pixmap
XmUNSPECIFIED_PIXMAP
CSG
XmNlabelString
XmCXmString
XmString
dynamic
CSG
XmNlabelType
XmCLabelType
unsigned char
XmSTRING
CSG
XmNmarginBottom
XmCMarginBottom
Dimension
dynamic
CSG
XmNmarginHeight
XmCMarginHeight
Dimension
2
CSG
XmNmarginLeft
XmCMarginLeft
Dimension
0
CSG
XmNmarginRight
XmCMarginRight
Dimension
dynamic
CSG
XmNmarginTop
XmCMarginTop
Dimension
dynamic
CSG
XmNmarginWidth
XmCMarginWidth
Dimension
dynamic
CSG
XmNmnemonic
XmCMnemonic
KeySym
NULL
CSG
XmNmnemonicCharSet
XmCMnemonicCharSet
String
XmFONTLIST_DEFAULT_TAG
CSG
XmNrecomputeSize
XmCRecomputeSize
Boolean
True
CSG
XmNstringDirection
XmCStringDirection
XmStringDirection
dynamic
CSG
XmPrimitive resource set
Name
Class
Type
Default
Access
XmNbottomShadowColor
XmCBottomShadowColor
Pixel
dynamic
CSG
XmNbottomShadowixmap
XmCBottomShadowPixmap
Pixmap
XmUNSPECIFIED_PIXMAP
CSG
XmNforeground
XmCForeground
Pixel
dynamic
CSG
XmNhelpCallback
XmCCallback
XtCallbackList
NULL
C
XmNhighlightColor
XmCHighlightColor
Pixel
dynamic
CSG
XmNhighlightOnEnter
XmCHighlightOnEnter
Boolean
False
CSG
XmNhighlightPixmap
XmCHighlightPixmap
Pixmap
dynamic
CSG
XmNhighlightThickness
XmCHighlightThickness
Dimension
0
CSG
XmNnavigationType
XmCNavigationType
XmNavigationType
XmNONE
CSG
XmNshadowThickness
XmCShadowThickness
Dimension
2
CSG
XmNtopShadowColor
XmCTopShadowColor
Pixel
dynamic
CSG
XmNtopShadowPixmap
XmCTopShadowPixmap
Pixmap
dynamic
CSG
XmNtraversalOn
XmCTraversalOn
Boolean
dynamic
G
XmNunitType
XmCUnitType
unsigned char
dynamic
CSG
XmNuserData
XmCUserData
XtPointer
NULL
CSG
Core resource set
Name
Class
Type
Default
Access
XmNaccelerators
XmCAccelerators
XtAccelerators
dynamic
CSG
XmNancestorSensitive
XmCSensitive
Boolean
dynamic
G
XmNbackground
XmCBackground
Pixel
dynamic
CSG
XmNbackgroundPixmap
XmCPixmap
Pixmap
XmUNSPECIFIED_PIXMAP
CSG
XmNborderColor
XmCBorderColor
Pixel
XtDefaultForeground
CSG
XmNborderPixmap
XmCPixmap
Pixmap
XmUNSPECIFIED_PIXMAP
CSG
XmNborderWidth
XmCBorderWidth
Dimension
0
CSG
XmNcolormap
XmCColormap
Colormap
dynamic
CG
XmNdepth
XmCDepth
int
dynamic
CG
XmNdestroyCallback
XmCCallback
XtCallbackList
NULL
C
XmNheight
XmCHeight
Dimension
dynamic
CSG
XmNinitialResourcesPersistent
XmCInitialResourcesPersistent
Boolean
True
C
XmNmappedWhenManaged
XmCMappedWhenManaged
Boolean
True
CSG
XmNscreen
XmCScreen
Screen
dynamic
CG
XmNsensitive
XmCSensitive
Boolean
True
CSG
XmNtranslations
XmCTranslations
XtTranslations
dynamic
CSG
XmNwidth
XmCWidth
Dimension
dynamic
CSG
XmNx
XmCPosition
Position
0
CSG
XmNy
XmCPosition
Position
0
CSG
Callback information
A pointer to the following structure is passed to each callback:
typedef struct
{
int reason;
XEvent * event;
} XmAnyCallbackStruct;
reason
Indicates why the callback was invoked.
event
Points to the XEvent that triggered the callback or is NULL
if this callback was not triggered due to an XEvent.
Translations
XmCascadeButton includes translations from Primitive.
XmCascadeButton includes the menu traversal translations from XmLabel.
These translations may not directly correspond to a
translation table.
Note that altering translations in #override
or #augment mode is undefined.
The translations for a CascadeButton in a MenuBar are listed below.
These translations may not directly correspond to a
translation table.
The translations for a CascadeButton in a PullDown or Popup
MenuPane are listed below.
In a Popup menu system, BMenu also performs the BSelect
actions.
These translations may not directly correspond to a
translation table.
The XmCascadeButton action routines are described below:
CleanupMenuBar():
In a MenuBar, disarms the CascadeButton and the menu and,
when the shell's keyboard focus policy is XmEXPLICT,
restores
keyboard focus to the widget that had the focus before the menu was
entered.
In a toplevel Pulldown MenuPane from a MenuBar, unposts the menu,
disarms the MenuBar CascadeButton and the MenuBar, and,
when the shell's keyboard focus policy is XmEXPLICT,
restores keyboard
focus to the widget that had the focus before the MenuBar was
entered.
In other Pulldown MenuPanes, unposts the menu.
In a Popup MenuPane, unposts the menu and,
when the shell's keyboard focus policy is XmEXPLICT,
restores keyboard focus to the
widget from which the menu was posted.
DoSelect():
Calls the callbacks in XmNcascadingCallback,
posts the submenu attached to the CascadeButton and
enables keyboard traversal within the menu.
If the CascadeButton does not have a submenu attached,
calls the callbacks in XmNactivateCallback,
the CascadeButton is activated and all posted menus in the cascade are
unposted.
Help():
Unposts all menus in the menu hierarchy and,
when the shell's keyboard focus policy is XmEXPLICT,
restores keyboard focus to
the widget that had the focus before the menu system was entered.
Calls the callbacks for XmNhelpCallback if any exist.
If there are no help callbacks for this widget, this action calls the
help callbacks for the nearest ancestor that has them.
KeySelect():
Calls the callbacks in XmNcascadingCallback,
and posts the submenu attached to the CascadeButton if keyboard
traversal is enabled in the menu.
If the CascadeButton does not have a submenu attached,
calls the callbacks in XmNactivateCallback,
the CascadeButton is activated and all posted menus in the cascade are
unposted.
MenuBarSelect():
Unposts any menus posted by the parent menu.
Arms both the CascadeButton and the MenuBar,
posts the associated submenu, and enables mouse traversal.
If the menu is already active, this event
disables keyboard traversal for the menu and returns
the menu to mouse traversal mode.
StartDrag():
Arms the CascadeButton, posts the associated submenu, and enables mouse
traversal.
If the menu is already active, this event
disables keyboard traversal for the menu and returns
the menu to mouse traversal mode.
Additional behavior
Posting a submenu calls the XmNcascadingCallback callbacks.
This widget has the additional behavior described below:
<EnterWindow>:
If keyboard traversal is enabled does nothing.
Otherwise, in a MenuBar that is armed,
unposts any MenuPanes associated with another MenuBar entry,
arms the CascadeButton, and posts the associated submenu.
In other menus,
arms the CascadeButton and posts the associated submenu after
the delay specified by XmNmappingDelay.
<LeaveWindow>:
If keyboard traversal is enabled does nothing.
Otherwise, in a MenuBar that is armed,
disarms the CascadeButton
if the submenu associated with the CascadeButton is not currently
posted or if there is no submenu associated with the CascadeButton.
In other menus,
if the pointer moves anywhere except into a submenu associated with the
CascadeButton, the CascadeButton is disarmed and its submenu is unposted.
Virtual bindings
The bindings for virtual keys are vendor specific.
For information about bindings for virtual buttons and keys, see
VirtualBindings(Xm).
