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package Chart::Clicker::Renderer::StackedArea;
use Moose;
extends 'Chart::Clicker::Renderer::Area';
use Graphics::Primitive::Brush;
use Graphics::Primitive::Path;
use Graphics::Primitive::Operation::Fill;
use Graphics::Primitive::Operation::Stroke;
use Graphics::Primitive::Paint::Gradient::Linear;
use Graphics::Primitive::Paint::Solid;
has '+additive' => ( default => sub { 1 } );
override('finalize', sub {
    my ($self) = @_;
    my $height = $self->height;
    my $width = $self->width;
    my $clicker = $self->clicker;
    my %accum;
    my $dses = $clicker->get_datasets_for_context($self->context);
    foreach my $ds (@{ $dses }) {
        foreach my $series (@{ $ds->series }) {
            # TODO if undef...
            my $ctx = $clicker->get_context($ds->context);
            my $domain = $ctx->domain_axis;
            my $range = $ctx->range_axis;
            my $lastx; # used for completing the path
            my @vals = @{ $series->values };
            my @keys = @{ $series->keys };
            my $startx;
            my $biggest;
            my @replays;
            for(0..($series->key_count - 1)) {
                my $key = $keys[$_];
                my $x = $domain->mark($width, $key);
                next unless defined($x);
                my $val = $vals[$_];
                if(exists($accum{$key})) {
                    # Store the previous value
                    push(@replays, [ $x, $accum{$key}]);
                    # Add this value to the accumulator, then replace
                    # it's value with the total
                    $val = $accum{$key} += $val;
                } else {
                    push(@replays, [ $x, 0 ]);
                    $accum{$key} = $val;
                }
                my $ymark = $range->mark($height, $val);
                next unless defined($ymark);
                my $y = $height - $ymark;
                if(defined($biggest)) {
                    $biggest = $y if $y > $biggest;
                } else {
                    $biggest = $y;
                }
                if($_ == 0) {
                    $startx = $x;
                    $self->move_to($x, $y);
                } else {
                    $self->line_to($x, $y);
                }
                $lastx = $x;
            }
            my $color = $self->clicker->color_allocator->next;
            my $op = Graphics::Primitive::Operation::Stroke->new;
            $op->preserve(1);
            $op->brush($self->brush->clone);
            $op->brush->color($color);
            $self->do($op);
            while(my $pt = pop(@replays)) {
                $self->line_to($pt->[0], $height - $range->mark($height, $pt->[1]));
            }
            $self->close_path;
            my $paint;
            if($self->opacity) {
                my $clone = $color->clone;
                $clone->alpha($self->opacity);
                $paint = Graphics::Primitive::Paint::Solid->new(
                    color => $clone
                );
            } elsif($self->fade) {
                my $clone = $color->clone;
                $clone->alpha($self->opacity);
                $paint = Graphics::Primitive::Paint::Gradient::Linear->new(
                    line => Geometry::Primitive::Line->new(
                        start => Geometry::Primitive::Point->new(x => 0, y => 0),
                        end => Geometry::Primitive::Point->new(x => 1, y => $biggest),
                    ),
                    style => 'linear'
                );
                $paint->add_stop(1.0, $color);
                $paint->add_stop(0, $clone);
            } else {
                $paint = Graphics::Primitive::Paint::Solid->new(
                    color => $color->clone
                );
            }
            my $fillop = Graphics::Primitive::Operation::Fill->new(
                paint => $paint
            );
            $self->do($fillop);
        }
    }
    return 1;
});
__PACKAGE__->meta->make_immutable;
no Moose;
1;
__END__
HideShow 52 lines of Pod
=head1 NAME
Chart::Clicker::Renderer::StackedArea - Stacked Area renderer
=head1 DESCRIPTION
Chart::Clicker::Renderer::StackedArea renders a dataset as line-like
polygons stacked atop one another.
=begin HTML
<p><img src="http://www.onemogin.com/clicker/chart-clicker-examples/area/stacked-area.png" width="500" height="250" alt="Stacked Area Chart" /></p>
=end HTML
=head1 SYNOPSIS
  my $ar = Chart::Clicker::Renderer::StackedArea->new({
      fade => 1,
      brush => Graphics::Primitive::Brush->new({
          width => 2
      })
  });
=head1 ATTRIBUTES
=head2 brush
Set/Get the brush that informs the line surrounding the area renders
individual segments.
=head2 fade
Set/Get the fade flag, which turns on or off a gradient in the area renderer.
=head2 opacity
Set the alpha value for the renderer, which makes things more or less opaque.
=head1 AUTHOR
Cory G Watson <gphat@cpan.org>
=head1 SEE ALSO
L<Chart::Clicker::Renderer>, perl(1)
=head1 LICENSE
You can redistribute and/or modify this code under the same terms as Perl
itself.