gamma table generator in perl

[Arduino] / Desk_LED_dimmer / gamma.pl

diff --git a/Desk_LED_dimmer/gamma.pl b/Desk_LED_dimmer/gamma.pl
new file mode 100755 (executable)
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--- /dev/null
+++ b/Desk_LED_dimmer/gamma.pl
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+#!/usr/bin/perl
+use warnings;
+use strict;
+
+# Generate an LED gamma-correction table for Arduino sketches.
+# https://learn.adafruit.com/led-tricks-gamma-correction/the-longer-fix
+
+my ( $gamma, $max_in, $max_out ) = @ARGV;
+ 
+$gamma   ||= 2.8;      # Correction factor
+$max_in  ||= 255,      # Top end of INPUT range
+$max_out ||= 255;      # Top end of OUTPUT range
+
+print "// gamma.pl $gamma $max_in $max_out\n"; 
+print "const uint8_t PROGMEM gamma[] = {";
+foreach my $i ( 0 .. $max_in ) {
+       print "," if $i > 0;
+       print "\n  " if $i % 15 == 0;
+       printf("%3d", int(
+               ( ($i / $max_in) ** $gamma ) * $max_out + 0.5)
+       );
+}
+print " };\n";
+