Tribblix: manual page: XmCascadeButtonGadget.3

XmCascadeButtonGadget(library call) XmCascadeButtonGadget(library call)

NAME

XmCascadeButtonGadget -- The CascadeButtonGadget widget class

SYNOPSIS

#include <Xm/CascadeBG.h>

DESCRIPTION

CascadeButtonGadget links two menu panes, a MenuBar to a menu pane,
or an OptionMenu to a menu pane.

It is used in menu systems and must have a RowColumn parent with its
XmNrowColumnType resource set to XmMENU_BAR, XmMENU_POPUP,
XmMENU_PULLDOWN, or XmMENU_OPTION.

It is the only gadget that can have a Pulldown menu pane attached to
it as a submenu. The submenu is displayed when this gadget is
activated within a PopupMenu, a PulldownMenu, or an OptionMenu. Its
visuals can include a label or pixmap and a cascading indicator when
it is in a Popup or Pulldown menu pane; or it can include only a
label or a pixmap when it is in an OptionMenu. The positioning of
the PulldownMenu with respect to the CascadeButton depends on the
XmNlayoutDirection resource of the MenuShell.

The default behavior associated with a CascadeButtonGadget depends on
the type of menu system in which it resides. By default, BSelect
controls the behavior of the CascadeButtonGadget. In addition, BMenu
controls the behavior of the CascadeButtonGadget if it resides in a
PopupMenu system. The actual mouse button used is determined by its
RowColumn parent. BMenu also performs the BSelect actions in all
types of menu systems.

A CascadeButtonGadget'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 CascadeButtonGadget within a Pulldown or Popup menu pane is
armed as the result of the user moving the mouse pointer into the
gadget, it does not immediately display its submenu. Instead, it
waits a short time to see if the arming was temporary (that is, the
user was simply passing through the gadget), or the user really
wanted the submenu posted. This delay is configurable using
XmNmappingDelay.

CascadeButtonGadget provides a single mechanism for activating the
gadget from the keyboard. This mechanism is referred to as a keyboard
mnemonic. If a mnemonic has been specified for the gadget, the user
may activate it by simply typing the mnemonic while the
CascadeButtonGadget is visible. If the CascadeButtonGadget is in a
MenuBar and the MenuBar does not have focus, the MAlt modifier must
be pressed with the mnemonic. Mnemonics are typically used to
interact with a menu using the keyboard.

If a CascadeButtonGadget is in a Pulldown or Popup menu pane 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 LabelGadget's default, which is 2.

CascadeButtonGadget uses the XmQTmenuSystem and
XmQTspecifyRenderTable traits.

Classes

CascadeButtonGadget inherits behavior, resources, and traits from the
Object, RectObj, XmGadget, and XmLabelGadget classes.

The class pointer is xmCascadeButtonGadgetClass.

The class name is XmCascadeButtonGadget.

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).

+---------------------------------------------------------------------------+
| XmCascadeButtonGadget |
|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 CascadeButtonGadget, and there is no
submenu attached to pop up. The activation occurs when a
mouse button is released or when the mnemonic associated
with the gadget is typed. 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
gadget when a CascadeButtonGadget is used within a Popup or
Pulldown menu pane and a submenu is attached. The
LabelGadget class resources XmNmarginBottom, XmNmarginLeft,
XmNmarginRight, and XmNmarginTop may be modified to ensure
that room is left for the cascade pixmap. The default
cascade pixmap in menus other than option menus is an arrow
pointing to the side of the menu where the submenu will
appear. The default for the CascadeButtonGadget in an
option menu is XmUNSPECIFIED_PIXMAP.

The positioning of the cascade pixmap to either the left of
right of the widget, and the direction of the arrow, depend
on the XmNlayoutDirection resource of the MenuShell.

XmNcascadingCallback
Specifies the list of callbacks that is called just prior
to the mapping of the submenu associated with the
CascadeButtonGadget. The reason sent by the callback is
XmCR_CASCADING.

XmNmappingDelay
Specifies the amount of time, in milliseconds, between when
a CascadeButtonGadget becomes armed and when it maps its
submenu. This delay is used only when the gadget is within
a Popup or Pulldown menu pane. The value must not be
negative.

XmNsubMenuId
Specifies the widget ID for the Pulldown menu pane to be
associated with this CascadeButtonGadget. The specified
menu pane is displayed when the CascadeButtonGadget becomes
armed. The menu pane must have been created with the
appropriate parentage depending on the type of menu used.
See XmCreatePulldownMenu(3), XmCreatePopupMenu(3), and
XmCreateOptionMenu(3) for more information on the menu
systems.

Inherited Resources

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 by an XEvent

Behavior

XmCascadeButtonGadget includes behavior from XmGadget.
XmCascadeButton includes the menu traversal behavior from XmLabel.
Additional XmCascadeButtonGadget behavior is described in the
following list (in a Popup menu system, <Btn3> also performs the
<Btn1> actions).

<Btn1Down>:
Unposts any menus posted by the parent menu. Arms the
CascadeButtonGadget, posts the associated submenu, enables
mouse traversal, and, in a MenuBar, arms the MenuBar. If
the menu is already active, this event disables keyboard
traversal for the menu and returns the menu to mouse
traversal mode.

<Btn1Up>: Calls the callbacks in XmNcascadingCallback, posts the
submenu attached to the CascadeButtonGadget and enables
keyboard traversal within the menu. If the
CascadeButtonGadget does not have a submenu attached, this
action calls the callbacks in XmNactivateCallback,
activates the CascadeButtonGadget, and unposts all posted
menus in the cascade.

<Key><osfActivate>:
Calls the callbacks in XmNcascadingCallback, and posts the
submenu attached to the CascadeButtonGadget if keyboard
traversal is enabled in the menu. If the
CascadeButtonGadget does not have a submenu attached, this
action calls the callbacks in XmNactivateCallback,
activates the CascadeButtonGadget, and unposts all posted
menus in the cascade. This action applies only to gadgets
in MenuBars, PulldownMenus, and PopupMenus. For a
CascadeButtonGadget in an OptionMenu, if the parent is a
manager, this action passes the event to the parent.

<Key><osfSelect>:
Calls the callbacks in XmNcascadingCallback, and posts the
submenu attached to the CascadeButtonGadget if keyboard
traversal is enabled in the menu. If the
CascadeButtonGadget does not have a submenu attached, this
action calls the callbacks in XmNactivateCallback,
activates the CascadeButtonGadget, and unposts all posted
menus in the cascade.

<Key><osfHelp>:
Unposts all menus in the menu hierarchy and, when the
shell's keyboard focus policy is XmEXPLICIT, 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.

<Key><osfCancel>:
In a MenuBar, disarms the CascadeButtonGadget and the menu
and, when the shell's keyboard focus policy is XmEXPLICIT,
restores keyboard focus to the widget that had the focus
before the menu was entered. For a CascadeButtonGadget in
an OptionMenu, if the parent is a manager, this action
passes the event to the parent.

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 XmEXPLICIT,
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 restores keyboard
focus to the widget from which the menu was posted.

<Enter>: If keyboard traversal is enabled does nothing. Otherwise,
in a MenuBar, unposts any MenuPanes associated with another
MenuBar entry, arms the CascadeButtonGadget, and posts the
associated submenu. In other menus, arms the
CascadeButtonGadget and posts the associated submenu after
the delay specified by XmNmappingDelay.

<Leave>: If keyboard traversal is enabled does nothing. Otherwise,
in a MenuBar, disarms the CascadeButtonGadget if the
submenu associated with the CascadeButtonGadget is not
currently posted or if there is no submenu associated with
the CascadeButtonGadget.

In other menus, if the pointer moves anywhere except into a
submenu associated with the CascadeButtonGadget, the
CascadeButtonGadget 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(3).

Object(3), RectObj(3), XmCascadeButtonHighlight(3),
XmCreateCascadeButtonGadget(3), XmCreatePulldownMenu(3),
XmCreatePopupMenu(3), XmCreateOptionMenu(3), XmGadget(3),
XmLabelGadget(3), XmRowColumn(3), XmVaCreateCascadeButtonGadget(3),
and XmVaCreateManagedCascadeButtonGadget(3).

XmCascadeButtonGadget(library call)