DRAWMUX(2) DRAWMUX(2)
NAME
drawmux - multiplex stream of draw requests
SYNOPSIS
include "drawmux.m";
drawmux := load Drawmux Drawmux->PATH;
init: fn(): (string, ref Draw->Display);
newviewer: fn(fd: ref Sys->FD);
DESCRIPTION
Drawmux puts itself between the invoking application and
/dev/draw (see draw(3)), so that the contents of the current
display can be replicated elsewhere.
Init returns a new Display (see draw-display(2)) represent-
ing a connection to a virtual display device. Subsequent
Draw requests to that display (see draw-intro(2)) are for-
warded to the underlying draw(3) device to appear on the
physical display, but can also replicated elsewhere, typi-
cally in a window on a remote display.
Newviewer prepares the virtual display end of a Drawmux con-
nection for each new viewer of the display created by a pre-
vious call to init. The file descriptor fd is a connection
to the viewer. The remote viewer must first write 24 bytes
on that connection, containing two decimal numbers (each 11
digits and a space), giving the identifier of a public
screen on the viewer's display, on which newviewer will
replicate the Drawmux display, and the log (base 2) of the
number of bits per pixel for windows created on that screen.
The remote viewer must then use Sys->export (see sys-
dial(2)) to export its /dev/draw, which newviewer expects to
find as the root of the exported hierarchy. Subsequent draw
operations on the Drawmux display will be replicated on the
public screen exported by the viewer. Shutting down the
connection shuts down the multiplexor for that viewer.
SEE ALSO
wm-dmview(1), draw-intro(2), draw(3)
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