ref: 0644aa11c120a581eec1d47c66208e08b946ec08
dir: /man/2/ir/
.TH IR 2
.SH NAME
ir \- infrared remote control module
.SH SYNOPSIS
.EX
include "ir.m";
ir := load Ir Ir->PATH; # for real remotes
simir := load Ir Ir->SIMPATH; # for keyboard simulator
init: fn(irc: chan of int, pidc: chan of int): int;
translate: fn(key: int): int;
.EE
.SH DESCRIPTION
Programs running with the Prefab
toolkit (see
.IR prefab-intro (2))
are controlled by an infrared remote
control device.
If such a device is not present, the system may simulate
it from the keyboard by loading the module in file
.BR Ir->SIMPATH .
Although originally designed for use with Prefab,
these modules are general enough to be used directly by non-Prefab
applications.
.PP
The
.B Ir
module defines codes
for representing the remote control keys.
Whether the remote is real or simulated, the
.B init
function does the appropriate actions to initialize the device, and then spawns
a process to return the codes on the
.I irc
channel.
The process ID of that process
is sent on the channel
.I pidc
when the process starts;
.BR init 's
caller must receive it.
It can be used to kill the controlling process when the application finishes.
.PP
The codes are:
.PP
.TP
.BR Ir\->ChanUP ", " Ir\->ChanDN
The Channel-Up and Channel-Down buttons.
The keyboard equivalents are
.B r
and
.BR c .
.TP
.B Ir\->Enter
The Enter button.
The keyboard equivalent is the \s-1SPACE\s0 bar.
.TP
.B Ir\->EOF
An end of file from the remote device.
After sending one, no more codes will be sent on
.IR irc .
.TP
.B Ir\->Error
An unknown or invalid input from the remote device.
.TP
.BR Ir\->FF ", " Ir\->Rew
The Fast-Forward and Rewind buttons.
The keyboard equivalents are
.B k
and
.BR j .
.TP
.B Ir\->Mute
The Mute button.
There is no keyboard equivalent.
.TP
.B Ir\->Power
The Power button.
The keyboard equivalent is the
.B Delete
key.
.TP
.B Ir\->Rcl
The Recall button.
The keyboard equivalent is
.BR x .
.TP
.B Ir\->Record
The Record button.
There is no keyboard equivalent.
.TP
.B Ir\->Select
The Select button.
The keyboard equivalent is the
.B Return
or
.B Enter
key.
.TP
.BR Ir\->Up ", " Ir\->Dn
The Up and Down buttons.
The keyboard equivalents are
.B i
and
.BR m .
.TP
.BR Ir\->VolUP ", " Ir\->VolDN
The Volume-Up and Volume-Down buttons.
The keyboard equivalents are
.B t
and
.BR v .
.TP
.B
Ir\->Zero\fR,\fP Ir\->One\fR,\fP Ir\->Two\fR, etc.
.PD
The digit buttons, 0 through 9.
The keyboard equivalents are the corresponding numeral keys.
.PP
The
.B translate
function converts the device's raw codes into the constants defined by
the module.
For example, with the simulated remote control,
.B translate('3')
returns
.BR Ir->Three .
.B Translate
is only necessary for programs that wish to manage their own simulation of the remote.
.PP
Programs
that drive the remote control directly,
must load the appropriate Ir implementation module and initialise it.
The following example uses the absence of a simulator module
to infer that a real remote control is available.
.PP
.EX
implement Irtest;
include "sys.m";
include "draw.m";
include "ir.m";
Irtest: module
{
init: fn(ctxt: ref Draw->Context, argv: list of string);
};
init(nil: ref Draw->Context, nil: list of string)
{
sys := load Sys Sys->PATH;
# First try the keyboard Ir simulator.
# If that is not present, use Ir directly.
ir := load Ir Ir->SIMPATH;
if(ir == nil)
ir = load Ir Ir->PATH;
if(ir == nil){
sys->print("Ir module not loaded: %r\en");
return;
}
irc := chan of int;
pidc := chan of int;
if(ir->init(irc, pidc) < 0){
sys->print("Can't initialize Ir device: %r\en");
return;
}
pid := <-pidc;
while((irraw := <-irc) != Ir->EOF) {
irval := ir->translate(irraw);
if(irval == Ir->Power)
break;
sys->print("command %d -> %d\en", irraw, irval);
}
kill(pid);
}
.EE
.PP
.IR Mux (1)
provides one model for the use of an infrared remote control to control
a group of applications.
.B Init
is invoked once by
.IR mux ,
and the codes then multiplexed between its applications as follows.
.I Mux
creates a graphics context for each application
(see
.IR draw-context (2)).
This context includes channels to the
.B mux
program and to the
.B Ir
device:
.B Draw->Context.ctomux
and
.BR Draw->Context.cinput .
Applications do not see the
.B Ir->Rcl
command.
Instead,
.I mux
program intercepts it and reactivates its own menu.
The following example establishes communication with
.I mux
and then reads
.B Ir
commands until it see
.BR Ir->Enter .
.PP
.EX
implement Command;
include "sys.m";
include "draw.m";
include "ir.m";
Command: module
{
init: fn(ref Draw->Context; list of string);
};
init(ctxt: ref Draw->Context; argv: list of string)
{
sys := load Sys Sys->PATH;
# Tell mux to start sending input.
ctxt.ctomux <-= Draw->AMstartinput;
for(;;) {
key := <-ctxt.cinput;
sys->print("command %d\en", key);
if(key == Ir->Enter)
break;
}
# Tell mux this thread is going away.
ctxt.ctomux <-= Draw->AMexit;
}
.EE
.SH SOURCE
.B /appl/lib/ir.b
.br
.B /appl/lib/irmpath.b
.br
.B /appl/lib/irsim.b
.SH SEE ALSO
.IR limbo (1),
.IR mux (1),
.IR intro (2),
.IR draw-intro (2),
.IR prefab-intro (2)