Once I tried to come up with a solution to mark some stuff (on a HTML page) with dynamic values from red to green based on these values. The positive values green and the negative ones red.
Today I stumbled over this piece of code again. I thought it might be optimizable and did some benchmarking. After I found nothing else to optimize in this snippet (suggestions?), I decided to post it. Maybe, someone will some day need a piece of code like this, too.
sub calcColor ($$$)
{
my ($min, $max, $value) = @_; # min = the minimal (possible)
+value
# max = the maximal (possible)
+value
# value = the value you want a
+color for
my $color; # be strict
my $all = ($value < 0 ? $min : $max);# calculate with minimal or max
+imal value
$all || return 'FFFF00'; # avoid divisions by zero
$color = sprintf('%.2X', 255 - int($value/$all*255)); #calculate and
+ make hex
return ($value < 0 # return
? 'FF'.$color.'00' # either a red
: $color.'FF00' # or a green
);
}