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.TH "" 3 "" "Version 3.0" "Free Widget Foundation"
.SH NAME
XfwfMenuBar
.SH DESCRIPTION
The MenuBar widget is a special kind of RowCol widget. It assumes
that all its children are PullDown buttons or other widgets that pop
up a menu. (But nothing will break if they are not.)  By default, the
children are arranged in a row, wrapping to the next row if the width
is not enough for all of them. But other arrangements are possible,
see the resources of the XfwfRowCol(3) widget.

The MenuBar attaches itself to the \fIpopup\fP callback of the menu shell
that is popped up by the children, and inserts itself in the list of
pointer grabs that Xt maintains. This is necessary to be able to drag
the mouse from one menu into another, popping down the first one and
popping up the second. If you use a RowCol widget instead of a
MenuBar, you will find that switching from one menu to the next
involves releasing the mouse and then pressing it again.

To find the menu shell, the children are asked for their \fIpopup\fP
resource. PullDown buttons have this resource, others may not.

The MenuBar widget introduces no new resources.

.SS "Public variables"

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XfwfMenuBar
Name	Class	Type	Default

.TE
.ps

.TP
.I "XtNframeType"

.hi

.nf
 frameType = XfwfRaised 
.fi

.eh

.TP
.I "XtNtraversalOn"

.hi

.nf
 traversalOn = False 
.fi

.eh

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XfwfRowCol
Name	Class	Type	Default
XtNstoreByRow	XtCStoreByRow	Boolean 	True 
XtNrows	XtCRows	Int 	0 
XtNcolumns	XtCColumns	Int 	0 
XtNalignment	XtCAlignment	Alignment 	XfwfTopLeft 
XtNshrinkToFit	XtCShrinkToFit	Boolean 	False 

.TE
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XfwfBoard
Name	Class	Type	Default
XtNabs_x	XtCAbs_x	Position 	0 
XtNrel_x	XtCRel_x	Float 	"0.0"
XtNabs_y	XtCAbs_y	Position 	0 
XtNrel_y	XtCRel_y	Float 	"0.0"
XtNabs_width	XtCAbs_width	Position 	0 
XtNrel_width	XtCRel_width	Float 	"1.0"
XtNabs_height	XtCAbs_height	Position 	0 
XtNrel_height	XtCRel_height	Float 	"1.0"
XtNhunit	XtCHunit	Float 	"1.0"
XtNvunit	XtCVunit	Float 	"1.0"
XtNlocation	XtCLocation	String 	NULL 

.TE
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XfwfFrame
Name	Class	Type	Default
XtNcursor	XtCCursor	Cursor 	None 
XtNframeType	XtCFrameType	FrameType 	XfwfRaised 
XtNframeWidth	XtCFrameWidth	Dimension 	0 
XtNouterOffset	XtCOuterOffset	Dimension 	0 
XtNinnerOffset	XtCInnerOffset	Dimension 	0 
XtNshadowScheme	XtCShadowScheme	ShadowScheme 	XfwfAuto 
XtNtopShadowColor	XtCTopShadowColor	Pixel 	compute_topcolor 
XtNbottomShadowColor	XtCBottomShadowColor	Pixel 	compute_bottomcolor 
XtNtopShadowStipple	XtCTopShadowStipple	Bitmap 	NULL 
XtNbottomShadowStipple	XtCBottomShadowStipple	Bitmap 	NULL 

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XfwfCommon
Name	Class	Type	Default
XtNtraversalOn	XtCTraversalOn	Boolean 	True 
XtNhighlightThickness	XtCHighlightThickness	Dimension 	2 
XtNhighlightColor	XtCHighlightColor	Pixel 	XtDefaultForeground 
XtNhighlightPixmap	XtCHighlightPixmap	Pixmap 	None 
XtNnextTop	XtCNextTop	Callback	NULL 
XtNuserData	XtCUserData	Pointer	NULL 

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Composite
Name	Class	Type	Default
XtNchildren	XtCChildren	WidgetList 	NULL 
insertPosition	XtCInsertPosition	XTOrderProc 	NULL 
numChildren	XtCNumChildren	Cardinal 	0 

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Core
Name	Class	Type	Default
XtNx	XtCX	Position 	0 
XtNy	XtCY	Position 	0 
XtNwidth	XtCWidth	Dimension 	0 
XtNheight	XtCHeight	Dimension 	0 
borderWidth	XtCBorderWidth	Dimension 	0 
XtNcolormap	XtCColormap	Colormap 	NULL 
XtNdepth	XtCDepth	Int 	0 
destroyCallback	XtCDestroyCallback	XTCallbackList 	NULL 
XtNsensitive	XtCSensitive	Boolean 	True 
XtNtm	XtCTm	XTTMRec 	NULL 
ancestorSensitive	XtCAncestorSensitive	Boolean 	False 
accelerators	XtCAccelerators	XTTranslations 	NULL 
borderColor	XtCBorderColor	Pixel 	0 
borderPixmap	XtCBorderPixmap	Pixmap 	NULL 
background	XtCBackground	Pixel 	0 
backgroundPixmap	XtCBackgroundPixmap	Pixmap 	NULL 
mappedWhenManaged	XtCMappedWhenManaged	Boolean 	True 
XtNscreen	XtCScreen	Screen *	NULL 

.TE
.ps

.SS "Exports"

The MenuBar widget has a method \fIprocess_menu\fP that can be used by
children (usually PullDown buttons) to pop up a menu and to register
it with the menu bar. If they do so, the menu bar is able to process
events elsewhere in the menu bar and pop down the menu in favour of
another one, when the user moves the mouse to another button in the
menu bar. A menu or a button is unable to do this by itself, since
they do not know what other menus are present.

To call the \fIprocess_menu\fP method, widgets should use the
\fIXfwfCallProcessMenu\fP function, which will check that the receiver of
the call is indeed a MenuBar widget. It returns \fITrue\fP if the
\fIprocess_menu\fP method could be called, otherwise \fIFalse\fP.

The value for \fIcursor\fP can also be \fINone\fP, in which case the cursor
from the menu's parent (the root window, usually) will be used
instead.

.nf
Boolean  XfwfCallProcessMenu( $, Widget  menu, Cursor  cursor)
.fi

.hi
{
    if (XtIsSubclass($, xfwfMenuBarWidgetClass)  $process_menu) {
	$process_menu($, menu, cursor);
	return True;
    } else
	return False;
}
.eh

.SS "Translations"

Since the MenuBar widget adds itself to the list of cascaded popups
that is maintained by Xt, it will receive pointer events when a menu
is popped up. If the event is a button release, the current menu will
have to be popped down.

	

.nf
<Btn1Up>: menu_popdown() 
.fi

.hi
.SS "Actions"

.TP
.I "menu_popdown

The \fImenu_popdown\fP action calls \fIXtPopdown\fP for the current menu,
if there is one.

.hi

.nf
void menu_popdown($, XEvent* event, String* params, Cardinal* num_params)
{
    if ($current_menu != NULL) {
	XtPopdown($current_menu);
	$current_menu = NULL;
    }
}
.fi

.eh

.hi

.hi
.SH "Importss"

.nf

.B incl
 <Xfwf/PullDown.h>
.fi

.nf

.B incl
 <X11/Shell.h>
.fi

.nf

.B incl
 <stdio.h>
.fi

.hi

.hi
.SS "Private variables"

A pointer to the currently popped up menu is kept in a private
variable \fIcurrent_menu\fP. The variable is set in the \fIprocess_menu\fP
method.

	

.nf
Widget  current_menu
.fi

.hi

.hi
.SS "Methods"

.nf
initialize(Widget  request, $, ArgList  args, Cardinal * num_args)
{
    $current_menu = NULL;
}
.fi

The \fIprocess_menu\fP method is provided for use by children (usually
PullDown buttons) to pop up their menus. If they call this method
instead of popping up the menu themselves, the menu bar has a chance
to intercept events for other buttons in the menu bar and pop down the
menu when the user clicks on another button in the menubar.

The method adds the appropriate (passive) global grabs, establishes an
Xt local grab and adds a callback to the menu, so that the menu bar
will be informed when the menu is popped down again.

.nf
process_menu($, Widget  menu, Cursor  cursor)
{
    if (menu == $current_menu) return;
    if ($current_menu) XtPopdown($current_menu);
    XtAddGrab($, True, False);
/*
    XtGrabButton(menu, AnyButton, AnyModifier, True, ButtonPressMask |
		 ButtonReleaseMask | EnterWindowMask | LeaveWindowMask
		 | PointerMotionMask, GrabModeAsync, GrabModeAsync,
		 None, cursor);
    XtGrabKey(menu, AnyKey, AnyModifier, True, GrabModeAsync,
	      GrabModeAsync);
*/
    XtAddCallback(menu, XtNpopdownCallback, popdown_cb, $);
    $current_menu = menu;
    XtPopup(menu, XtGrabNonexclusive);
}
.fi

.hi

.hi
.SH "Utilities"

The \fIpopdown_cb\fP routine is a callback that is attached to the
currently popped up menu. When the menu pops down, the routine removes
the grabs and resets \fIcurrent_menu\fP to \fINULL\fP.

.nf
popdown_cb(Widget  menu, XtPointer  client_data, XtPointer  call_data)
{
    Widget $ = (Widget) client_data;

    XtRemoveCallback(menu, XtNpopdownCallback, popdown_cb, $);
/*
    XtUngrabKey(menu, AnyKey, AnyModifier);
    XtUngrabButton(menu, AnyButton, AnyModifier);
    XtRemoveGrab($);
*/
    $current_menu = NULL;
}
.fi

.hi