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