scripts/thinkpad/blc.pl

#!/usr/bin/perl -w

# Files containing current and max brightness values
my $cur_file = "/sys/class/backlight/intel_backlight/brightness";
my $max_file = "/sys/class/backlight/intel_backlight/max_brightness";
my $last_file = "/home/jpm/.config/blc.last";

sub to_percent
{
        my $value = shift;
        if ($value eq "Permission Denied") {
                return $value;
        } else {
                $value = int($value/get_max()*100);
                return $value . '%';
        }
}

sub get_offset
{
        return int(get_max()/100);
}

sub get_current
{
        open(my $c,'<',"$cur_file");
        my $current = <$c>;
        close $c;
        chomp $current;
        return $current;
}

sub get_max
{
        open(my $m,'<',"$max_file");
        my $max = <$m>;
        close $m;
        chomp $max;
        return $max;
}

sub get_min
{
        return int((get_max()/100)+2);
}

sub writable
{
        if (! -w $cur_file) {
                return 0;
        } else {
                return 1;
        }
}

sub increment
{
        if (writable()) {
                my $current = get_current();
                my $max = get_max();
                my $target = $current+get_offset();
                if ($target > $max) {
                        $target = $max;
                }
                open(my $c,'>',"$cur_file");
                print $c $target;
                close $c;
                return $target;
        } else {
                return "Permission Denied";
        }
}

sub decrement
{
        if (writable()) {
                my $current = get_current();
                my $min = get_min();
                my $target = $current-get_offset();
                if ($target < $min) {
                        $target = $min;
                }
                open(my $c,'>',"$cur_file");
                print $c $target;
                close $c;
                return $target;
        } else {
                return "Permission Denied";
        }
}

sub set
{
        my $value = shift;
        if (writable()) {
                $current = get_current();
                if ($value > $current) {
                        for (my $i=$current;$i<=$value;$i++) {
                                open(my $c,'>',"$cur_file");
                                print $c $i;
                                close $c;
                        }
                } else {
                        for (my $i=$current;$i>=$value;$i--) {
                                open(my $c,'>',"$cur_file");
                                print $c $i;
                                close $c;
                        }
                }
                return $value;
        } else {
                return "Permission Denied";
        }
}

sub help
{
        print "
Backlight Control

Usage: blc.pl [--silent|--notify] [OPTION] [VALUE]

With no option the backlight information is printed as JSON.

Output printed to STDOUT unless:

--silent  Do not display output (overrides --notify)
--notify  Send output to notification daemon. --notify=N will
          change the display duration in ms. Default is 200ms

Output option must preceed the first Action option.

Actions:

= VALUE   Set backlight to specific value. VALUE greater than
          100 will be treated as absolute value. VALUE eqaul to
          or less than 100 will be treated as a percentage
++        Increment by 1%
+= VALUE  Increment by VALUE percent
--        Decrement by 1%
-= VALUE  Decrement by VALUE percent

Actions corrected to 1% or 100% if over or under. All actions
provide output as a percentage, with the % symbol.

Final percentage printed as below, skipping other options.

Print:

==        Print current absolute value
^         Print maximum absolute value
%         Print current percentage (does not include % symbol)
--help    Help (not impacted by --silent or --notify)
--HELP    Advanced help (same as above)

Any other option will be printed literally";
}

sub advanced
{
        $current = get_current();
        $max = get_max();
        print ".

Print functions can be strung together but command will exit
with the first non-print option. eg.

        \$ blc.pl == / ^
        21/100
        \$ blc.pl == ++
        ('==' ignored)
        (Backlight incremented)

Escape options with \\ in quotes to display them literally. eg.

        \$ blc.pl == / ^ '\\=' % \'\\%\'
        " . $current . "/" . $max . "=" . int($current/$max*100) . "%

Only one \'\\' is removed per block. eg.

        \$ blc.pl '\\% \\'
        % \\

";
}

my $current = get_current();
my (@output, $target, $silent, $notify);

if (scalar @ARGV) {
        for (my $i=0;$i<scalar @ARGV;$i++) {
                if ($ARGV[$i] eq '++') {
                        $target = increment();
                        @output = to_percent($target);
                        last;
                } elsif ($ARGV[$i] eq '+=') {
                        for (my $i=0;$i<scalar @ARGV;$i++) {
                                if ($ARGV[$i] eq '+=') {
                                        if (defined $ARGV[($i+1)]) {
                                                $count = $ARGV[($i+1)];
                                                for (my $j=0;$j<$count;$j++) {
                                                        $target = increment();
                                                        if ($target eq
                                                        "Permission Denied") {
                                                                last;
                                                        }
                                                }
                                                @output = to_percent($target);
                                        } else {
                                                @output =
                                                ("No value after $ARGV[$i]");
                                        }
                                        last;
                                }
                        }
                        last;
                } elsif ($ARGV[$i] eq '--') {
                        $target = decrement();
                        @output = to_percent($target);
                        last;
                } elsif ($ARGV[$i] eq '-=') {
                        for (my $i=0;$i<scalar @ARGV;$i++) {
                                if ($ARGV[$i] eq '-=') {
                                        if (defined $ARGV[($i+1)]) {
                                                $count = $ARGV[($i+1)];
                                                for (my $j=0;$j<$count;$j++) {
                                                        $target = decrement();
                                                        if ($target eq
                                                        "Permission Denied") {
                                                                last;
                                                        }
                                                }
                                                @output = to_percent($target);
                                        } else {
                                                @output =
                                                ("No value after $ARGV[$i]");
                                        }
                                        last;
                                }
                        }
                        last;
                } elsif ($ARGV[$i] eq '=') {
                        $target = $ARGV[($i+1)];
                        if (defined $target) {
                                if ($target < 1) {
                                        $target = set(get_min());
                                } elsif ($target > get_max()) {
                                        $target = set(get_max());
                                } elsif ($target > 100) {
                                        $target = set($target);
                                } else {
                                        $target = set(
                                                int((get_max()*$target/100)+1)
                                        );
                                }
                                if ($target eq "Permission Denied") {
                                        @output = $target;
                                } else {
                                        @output = to_percent($target);
                                }
                                last;
                        } else {
                                @output = ("No value after $ARGV[$i]");
                                last;
                        }
                } elsif ($ARGV[$i] eq '%') {
                        push @output,int(get_current()/get_max()*100);
                } elsif ($ARGV[$i] eq '^') {
                        push @output,get_max();
                } elsif ($ARGV[$i] eq '==') {
                        push @output,get_current();
                } elsif ($ARGV[$i] eq '--help') {
                        help();
                        print " (see --HELP).\n\n";
                        exit();
                } elsif ($ARGV[$i] eq '--HELP') {
                        help();
                        advanced();
                        exit();
                } elsif ($ARGV[$i] eq '--silent') {
                        $silent = 'TRUE';
                } elsif ($ARGV[$i] =~ /^--notify/) {
                        $notify = 'TRUE';
                        if ($ARGV[$i] =~ /=[0-9]+$/) {
                                $duration = $ARGV[$i];
                                $duration =~ s/.*=([0-9]+)/$1/;
                        } else {
                                $duration = 200;
                        }
                } else {
                        my $add = $ARGV[$i];
                        $add =~ s/\\//;
                        push @output,$add;
                }
        }
} else {
        @output = (
                '{"Backlight":{"Max":"'
                . get_max()
                . '","Current":"'
                . get_current()
                . '","Percentage","'
                .  int(get_current()/get_max()*100)
                . '%"}}'
        );
}


open(my $fh,'>',$last_file);
print $fh get_current();
close($fh);

if ($silent) {
        exit();
} elsif ($notify) {
        # Don't output anything if the value didn't change
        if ($current == get_current()) {
                exit();
        }
        my $concat;
        foreach (@output) {
                $concat .= $_;
        }
        system "notify-send --urgency=normal -i "
                . "/usr/share/icons/Papirus-Dark-Grey/48x48/status/"
                . "notification-display-brightness.svg -t "
                . $duration
                . ' "'
                . $concat
                . '"';
        exit();
} else {
        print foreach @output;
        print "\n";
        exit();
}