Non-optimal values for tick marks

[koknat]

By default Chart::Clicker chooses non-optimal values for tick marks (such as 0.30, 1.40, 2.50, 3.60, 4.70, 5.80).

I created a subroutine getrange() which creates tick marks to produce a chart which is easier to read.
In the example above, if getrange() is given a min of 0.30 and a max of 5.80, the tick marks returned will be [0, 1, 2, 3, 4, 5, 6]

my $Yrange = getrange( $min, $max, { integer => 1 } );
$ctx->range_axis->tick_values($Yrange);   

sub getrange {
    my ( $min, $max, $options ) = @_;
    # $min and $max are the minimum and maximum values of the input data
    return if not defined $min or not defined $max;
    my $span = $max - $min;
    my $n = substr( sprintf( "%.6e", $span ), 0, 8 );     # First few number 1.000000 to 9.999999
    my $e = substr( sprintf( "%.6e", $span ), 9, 11 );    # exponent with sign such as +01
    my $step;
    if ( $n > 5 ) {
        $step = 1 * 10**($e);                            # 5.01 to 9.99
    } elsif ( $n > 2 ) {
        $step = 5 * 10**( $e - 1 );                      # 2.01 to 3.00
    } else {
        $step = 2 * 10**( $e - 1 );                      # 1.00 to 2.00
    }
    if ( $options->{integer} ) {
        # This forces steps to be integers.  If max is 2.2, then step is 1 (not 0.5)
        use POSIX;
        $step = ceil($step);
    }
    my $range;
    if ( $max/$step == int($max/$step) ) {
        $range = [ map { $_ * $step }  int( $min / $step ) .. int( $max / $step ) ];
    } else {
        $range = [ map { $_ * $step }  int( $min / $step ) .. int( $max / $step ) + 1 ];
    }
    return $range;
}  
sub test_getrange {
    my @minmax = ( 0.30, 5.80,  0, 0.85,  0, 1.1,  0, 2.2,  0, 5.8,  0, 8,  0, 15,  0, 28,  0, 44,  0, 58,  0, 88,  0, 100,  0, 102,  0, 1020,  -7, 21,  18, 45,  18, 49 );
    while (@minmax) {
        my $min = shift @minmax;
        my $max = shift @minmax;
        my $range = getrange( $min, $max, { integer => 1 } );
        say "\n$min  $max\n    " . join ' ', @{$range};
    }
    exit 0;
}

[gphat]

I'd be happy to accept a patch that adds a new DivisionType (See Axis.pm and DivisionType.pm).

[gphat]

Oops, closed accidentally. :)

[gphat]

Closing due to inactivity.