.\" Copyright (c) 2003-2023 Julien Nadeau Carriere <vedge@csoft.net>
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.Dd December 21, 2022
.Dt AG_UCOMBO 3
.Os Agar 1.7
.Sh NAME
.Nm AG_UCombo
.Nd agar button-triggered drop-down menu widget
.Sh SYNOPSIS
.Bd -literal
#include <agar/core.h>
#include <agar/gui.h>
.Ed
.Sh DESCRIPTION
.\" IMAGE(/widgets/AG_UCombo.png, "A collapsed AG_UCombo")
The
.Nm
widget displays an
.Xr AG_Button 3
which triggers the expansion of drop-down menu (a window containing an
.Xr AG_Tlist 3 )
when pressed.
The drop-down menu collapses if the user selects an item, or clicks outside
of the
.Nm
area.
.Sh INHERITANCE HIERARCHY
.Xr AG_Object 3 ->
.Xr AG_Widget 3 ->
.Nm .
.Sh INITIALIZATION
.nr nS 1
.Ft "AG_UCombo *"
.Fn AG_UComboNew "AG_Widget *parent" "Uint flags"
.Pp
.Ft "void"
.Fn AG_UComboSizeHint "AG_UCombo *com" "const char *text" "int nitems"
.Pp
.Ft "void"
.Fn AG_UComboSizeHintPixels "AG_UCombo *com" "int w" "int h"
.Pp
.nr nS 0
The
.Fn AG_UComboNew
function allocates, initializes, and attaches a new
.Nm
widget.
Acceptable
.Fa flags
include:
.Bl -tag -width "AG_UCOMBO_SCROLLTOSEL "
.It AG_UCOMBO_SCROLLTOSEL
Scroll to initial selection if it is not visible.
.It AG_UCOMBO_HFILL
Expand horizontally in parent container.
.It AG_UCOMBO_VFILL
Expand vertically in parent container.
.It AG_UCOMBO_EXPAND
Shorthand for
.Dv AG_UCOMBO_HFILL | AG_UCOMBO_VFILL .
.El
.Pp
.Fn AG_UComboSizeHint
arranges for the
.Xr AG_Tlist 3
widget displayed on popup to request a size large enough to display the given
number of items.
The
.Fn AG_UComboSizeHintPixels
variant specifies the size of the list in pixels.
.Sh EVENTS
The
.Nm
widget generates the following events:
.Pp
.Bl -tag -compact -width 2n
.It Fn ucombo-selected "AG_TlistItem *item"
An item was selected.
.It Fn ucombo-expanded "void"
The drop-down menu is now visible.
May be used to populate
.Va list .
.It Fn ucombo-collapsed "void"
The drop-down menu is now hidden.
.El
.Sh STRUCTURE DATA
For the
.Ft AG_UCombo
object:
.Pp
.Bl -tag -compact -width "AG_Button *button "
.It Ft AG_Tlist *list
The
.Xr AG_Tlist 3
displayed by
.Nm
when expanded, or NULL if collapsed (RO).
.It Ft AG_Button *button
The
.Xr AG_Button 3
which triggers expansion (RO).
.El
.Sh EXAMPLES
The following code fragment generates a drop-down menu and reacts to
a selection event by displaying a text dialog:
.Bd -literal -offset indent
.\" SYNTAX(c)
static void
ComboExpanded(AG_Event *event)
{
	AG_UCombo *com = AG_UCOMBO_SELF();
	AG_Tlist *tl = com->list;

	AG_TlistAdd(tl, NULL, "Foo");
	AG_TlistAdd(tl, NULL, "Bar");
}

static void
ComboSelected(AG_Event *event)
{
	AG_TlistItem *item = AG_TLISTITEM_PTR(1);

	AG_TextMsg(AG_MSG_INFO, "Selected item: %s", item->text);
}

AG_UCombo *com;

com = AG_UComboNew(NULL, 0);
AG_SetEvent(com, "ucombo-expanded", ComboExpanded, NULL);
AG_SetEvent(com, "ucombo-selected", ComboSelected, NULL);
.Ed
.Sh SEE ALSO
.Xr AG_Button 3 ,
.Xr AG_Combo 3 ,
.Xr AG_Intro 3 ,
.Xr AG_Tlist 3 ,
.Xr AG_Widget 3 ,
.Xr AG_Window 3
.Sh HISTORY
The
.Nm
widget first appeared in Agar 1.0.
"ucombo-expanded" and "ucombo-selected" appeared in Agar 1.7.0.