Croaks when all data points have the same value

[gphat]

Croaks when all data points have the same value

[djzort]

You can do something like

                # if all the values are the same, then manually set min and max
                unless ($series->range->span) {
                    $series->range->max($i->{values}->[0] + 1);
                    $series->range->min($i->{values}->[0] - 1);
                }

or perhaps +/- 5%

                # if all the values are the same, then manually set min and max
                unless ($series->range->span < 1) {
                    $series->range->max($i->{values}->[0] * 1.05);
                    $series->range->min($i->{values}->[0] * 0.95);
                }

[djzort]

where $series is...

my $series = Chart::Clicker::Data::Series->new( %$i );

[koknat]

Thanks, that worked very well.

BTW, the reason that all data points have the same value is that I run chart::clicker in an automated process, on real data. Occasionally all data points are equal.

[djzort]

I have a similar use case, were we are graphing the channel frequency of a device. Which shouldn't actually change very often :)

[gphat]

Could you try using a fudge amount on the axis?

$ctx->range_axis->fudge_amount(.015);

This will add a small amount of space above and below (effectively increasing the range) and maybe preventing that error.

[djzort]

fudge_amount probably wont give you what you are after if the values are all 0. (since 0 - 0 * 0.015 is still 0)

here is the code that it uses...

    if($self->fudge_amount) {
        my $span = $self->range->span;
        my $lower = $self->range->lower;
        $self->range->lower($lower - abs($span * $self->fudge_amount));
        my $upper = $self->range->upper;
        $self->range->upper($upper + ($span * $self->fudge_amount));
    }

People should be careful to drop the minimum value below zero (to negative) only if that value is appropriate in the graph. also be careful that the fudge amount doesn't expose a meaningless negative value in the axis.

So this is probably better in those cases, with no fudge_amount

                # if all the values are the same, then manually set min and max
                unless ($series->range->span) {
                    $series->range->max($i->{values}->[0] + 1);
                    my $min = $i->{values}->[0] -1;
                    $min = 0 if $min < 0;
                    $series->range->min($min)
                }

though, IMO you should always have at least a fudge_around value of 0.05 - simply so that if a plateau in values appears that people don't confuse it with truncated graphing. noting the exception for going negative

[koknat]

Thanks djzort, I used your code.

There are also times where I only have one data point. A chart is somewhat meaningless, but I'd still rather have a flat-line chart than no chart at all. As a workaround, I push an identical data point onto my $i->{values}

[djzort]

maybe put this in the examples/ directory?