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.Dd November 17, 2007
.Dt AG_SOCKET 3
.Os
.ds vT Agar API Reference
.ds oS Agar 1.3
.Sh NAME
.Nm AG_Socket
.Nd agar socket widget
.Sh SYNOPSIS
.Bd -literal
#include <agar/core.h>
#include <agar/gui.h>
.Ed
.Sh DESCRIPTION
The
.Nm
widget is a place holder for one or more drag-and-droppable
.Xr AG_Icon 3
widgets (or subclasses of it).
.Nm
also provides a boolean
.Sq state
binding and a numerical
.Sq count
binding.
.Sh INHERITANCE HIERARCHY
.Xr AG_Object 3 ->
.Xr AG_Widget 3 ->
.Nm .
.Sh INITIALIZATION
.nr nS 1
.Ft "AG_Socket *"
.Fn AG_SocketNew "AG_Widget *parent" "Uint flags"
.Pp
.Ft "AG_Socket *"
.Fn AG_SocketFromSurface "AG_Widget *parent" "Uint flags" "AG_Surface *s"
.Pp
.Ft "AG_Socket *"
.Fn AG_SocketFromBMP "AG_Widget *parent" "Uint flags" "const char *file"
.Pp
.Ft void
.Fn AG_SocketInsertFn "AG_Socket *socket" "int (*fn)(AG_Socket *, AG_Icon *)"
.Pp
.Ft void
.Fn AG_SocketRemoveFn "AG_Socket *socket" "void (*fn)(AG_Socket *, AG_Icon *)"
.Pp
.Ft void
.Fn AG_SocketOverlayFn "AG_Socket *socket" "AG_EventFn fn" "const char *fmt" "..."
.Pp
.Ft void
.Fn AG_SocketSetPadding "AG_Socket *socket" "int left" "int right" "int top" "int bottom"
.Pp
.Ft void
.Fn AG_SocketBgRect "AG_Socket *socket" "Uint width" "Uint height"
.Pp
.Ft void
.Fn AG_SocketBgCircle "AG_Socket *socket" "Uint radius"
.Pp
.Ft void
.Fn AG_SocketBgPixmap "AG_Socket *socket" "AG_Surface *s"
.Pp
.Ft void
.Fn AG_SocketBgPixmapNODUP "AG_Socket *socket" "AG_Surface *s"
.Pp
.nr nS 0
The
.Fn AG_SocketNew
function allocates, initializes, and attaches a new
.Nm
widget.
The
.Fn AG_SocketFromSurface
and
.Fn AG_SocketFromBMP
variants also set a background image for the socket, typically used to show
the type of icons that can be drag-and-dropped onto the socket.
The
.Fa flags
may include:
.Pp
.Bl -tag -width "AG_SOCKET_STICKY_STATE "
.It AG_SOCKET_STICKY_STATE
Mouse click should toggle the boolean state.
.El
.Pp
The
.Fn AG_SocketInsertFn
function configures a callback routine
.Fn fn
that will be invoked whenever the user tries to drop an icon onto the
socket.
A pointer to the socket and the icon being dropped will be passed to that
function.
Typically, this routine will use
.Fn AG_SocketInsertIcon
to assign the icon to the socket.
If
.Fn fn
returns 1, the drag-and-drop item will be destroyed.
.Pp
The
.Fn AG_SocketRemoveFn
function registers a callback routine that will be invoked before an icon
is removed from a socket.
.Pp
The
.Fn AG_SocketOverlayFn
registers a routine that will be invoked in rendering context to draw items
on top of the socket (and any contained icons).
.Pp
The
.Fn AG_SocketSetPadding
function sets the padding around the socket's icon area in pixels.
.Pp
.Fn AG_SocketBgRect
configures the socket to use a rectangular shape of the given
dimensions in pixels.
.Pp
.Fn AG_SocketBgCircle
arranges for the socket to use a circular shape of the given radius in pixels.
.Pp
.Fn AG_SocketBgPixmap
uses the given surface as background image.
The
.Fn AG_SocketBgPixmapNODUP
variant prevents the surface from being copied.
.Sh EVENTS
The
.Nm
widget reacts to the following events:
.Pp
.Bl -tag -compact -width "window-mousebuttondown "
.It window-mousemotion
Toggle the
.Dv AG_SOCKET_MOUSEOVER
flag and raise the
.Sq socket-mouseoverlap
event whenever the cursor moves in and out of the socket area.
If the cursor moves out of the area (and
.Dv AG_SOCKET_STICKY_STATE
is not set), the boolean state reverts to 0.
.It window-mousebuttondown
Set the boolean state of the socket to 1.
If the socket contains an icon, start the drag-and-drop process.
.It window-mousebuttonup
Set the boolean state of the socket back to 0, unless the
.Dv AG_SOCKET_STICKY_STATE
flag is set.
.El
.Pp
The
.Nm
widget generates the following events:
.Pp
.Bl -tag -compact -width 2n
.It Fn socket-mouseoverlap "int state"
Cursor has moved inside or outside socket area.
.It Fn socket-click "int state"
User has clicked on the socket area.
.El
.Sh BINDINGS
The
.Nm
widget provides the following bindings.
.Pp
.Bl -tag -compact -width "BOOL *state "
.It Va BOOL *state
A generic boolean state associated with the socket.
.It Va INT *count
A generic "count" associated with the socket.
Typically used when the socket contains a stack of items.
.El
.Sh EXAMPLES
See
.Pa demos/sockets
in the Agar source distribution.
.Sh STRUCTURE DATA
For the
.Ft AG_Socket
object:
.Pp
.Bl -tag -width "AG_Icon *icon "
.It Ft AG_Icon *icon
Icon in socket or NULL (read-only).
.El
.Sh SEE ALSO
.Xr AG_Button 3 ,
.Xr AG_Pixmap 3 ,
.Xr AG_Surface 3 ,
.Xr AG_Intro 3 ,
.Xr AG_Widget 3 ,
.Xr AG_Window 3
.Sh HISTORY
The
.Nm
widget first appeared in Agar 1.0.