NAME
MIDI::RtController::Filter::CC - Control-change based RtController filters
VERSION
version 0.0603
SYNOPSIS
use curry;
use MIDI::RtController ();
use MIDI::RtController::Filter::CC ();
my $control = MIDI::RtController->new(
input => 'keyboard',
output => 'usb',
);
my $filter = MIDI::RtController::Filter::CC->new(rtc => $control);
$filter->control(1); # CC#01 = mod-wheel
$filter->channel(0);
$filter->range_bottom(10);
$filter->range_top(100);
$filter->range_step(2);
$filter->time_step(0.25);
$control->add_filter('breathe', all => $filter->curry::breathe);
$control->run;DESCRIPTION
MIDI::RtController::Filter::CC is a (growing) collection of control-change based MIDI::RtController filters.
Passing all to the add_filter method means that any MIDI event will cause this filter to be triggered.
Making filters
All filter methods must accept the object, a MIDI device name, a delta-time, and a MIDI event ARRAY reference, like:
sub breathe ($self, $device, $delta, $event) {
return 0 if $self->running;
my ($event_type, $chan, $control, $value) = $event->@*;
...
return $boolean;
}A filter also must return a boolean value. This tells MIDI::RtController to continue processing other known filters or not.
ATTRIBUTES
rtc
$rtc = $filter->rtc;The required MIDI::RtController instance provided in the constructor.
channel
$channel = $filter->channel;
$filter->channel($number);The current MIDI channel value between 0 and 15.
Default: 0
control
$control = $filter->control;
$filter->control($number);Return or set the control change number between 0 and 127.
Default: 1 (mod-wheel)
value
$value = $filter->value;
$filter->value($number);Return or set the control change value. This is a generic setting that can be used by filters to set state. This often a whole number between 0 and 127, but can take any number.
Default: 0
initial_point
$initial_point = $filter->initial_point;
$filter->initial_point($number);Return or set the control change initial point number between 0 and 127.
Default: 0
range_bottom
$range_bottom = $filter->range_bottom;
$filter->range_bottom($number);The current iteration lowest number value.
Default: 0
range_top
$range_top = $filter->range_top;
$filter->range_top($number);The current iteration highest number value.
Default: 127
range_step
$range_step = $filter->range_step;
$filter->range_step($number);A number greater than zero representing the current iteration step size between bottom and top.
Default: 1
time_step
$time_step = $filter->time_step;
$filter->time_step($number);The current iteration step in seconds (probably fractions).
Default: 0.25 (a quarter of a second)
step_up
$step_up = $filter->step_up;
$filter->step_up($number);The current iteration upward step.
Default: 2
step_down
$step_down = $filter->step_down;
$filter->step_down($number);The current iteration downward step.
Default: 1
running
$running = $filter->running;
$filter->running($boolean);Are we running a filter?
Default: 0
stop
$stop = $filter->stop;
$filter->stop($boolean);Stop running a filter.
Default: 0
METHODS
new
$filter = MIDI::RtController::Filter::CC->new(%arguments);Return a new MIDI::RtController::Filter::CC object.
single
$control->add_filter('single', all => $filter->curry::single);This filter sets a single control change message, over the MIDI channel once.
breathe
$control->add_filter('breathe', all => $filter->curry::breathe);This filter sets the running flag, then iterates between the range_bottom and range_top by range_step increments, sending a control change message, over the MIDI channel every iteration, until stop is seen.
Passing all means that any MIDI event will cause this filter to be triggered.
scatter
$control->add_filter('scatter', all => $filter->curry::scatter);This filter sets the running flag, chooses a random number between the range_bottom and range_top, and sends that as the value of a control change message, over the MIDI channel, every iteration, until stop is seen.
The initial_point is used as the first CC# message, then the randomization takes over.
stair_step
$control->add_filter('stair_step', all => $filter->curry::stair_step);This filter sets the running flag, uses the initial_point for the fist CC# message, then adds step_up or subtracts step_down from that number successively, sending the value as a control change message, over the MIDI channel, every iteration, until stop is seen.
ramp
$control->add_filter('ramp', all => $filter->curry::ramp);This filter ramps-up (or down) a control change message, over the MIDI channel, from range_bottom until the range_top is reached.
SEE ALSO
The eg/*.pl program(s) in this distribution
AUTHOR
Gene Boggs <gene.boggs@gmail.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2025 by Gene Boggs.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.