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#==========================================================================
#              Copyright (c) 1995-1998 Martien Verbruggen
#--------------------------------------------------------------------------
#
#   Name:
#       GD::Graph::axestype.pm
#
# $Id: axestype.pm,v 1.45 2007/04/26 03:16:09 ben Exp $
#
#==========================================================================

package GD::Graph::axestype;

($GD::Graph::axestype::VERSION) = '$Revision: 1.45 $' =~ /\s([\d.]+)/;

use strict;
 
use GD::Graph;
use GD::Graph::utils qw(:all);
use Carp;

@GD::Graph::axestype::ISA = qw(GD::Graph);

use constant PI => 4 * atan2(1,1);

my %Defaults = (
 
    # Set the length for the 'short' ticks on the axes.
    x_tick_length           => 4,
    y_tick_length           => 4,
 
    # Do you want ticks to span the entire width of the graph?
    x_long_ticks            => 0,
    y_long_ticks            => 0,
 
    # Number of ticks for the y axis
    y_tick_number       => 5,
    x_tick_number       => undef,       # CONTRIB Scott Prahl
    x_tick_offset       => 0,           # CONTRIB Damon Brodi
 
    # Skip every nth label. if 1 will print every label on the axes,
    # if 2 will print every second, etc..
    x_label_skip        => 1,
    y_label_skip        => 1,

# When skipping labels, also skip the last one.
    x_last_label_skip	=> 0,

# Do we want ticks on the x axis?
    x_ticks             => 1,
    x_all_ticks         => 0,

# Where to place the x and y labels
    x_label_position    => 3/4,
    y_label_position    => 1/2,

# vertical printing of x labels
    x_labels_vertical   => 0,
 
    # Draw axes as a box? (otherwise just left and bottom)
    box_axis            => 1,

# Disable axes?
    # undef -> all axes, 0 -> Only line for bars, other -> no axes at all.
    no_axes             => undef,
 
    # Use two different axes for the first and second dataset. The first
    # will be displayed using the left axis, the second using the right
    # axis. You cannot use more than two datasets when this option is on.
    two_axes            => 0,

# Which axis to use for each dataset. This only is in effect when
    # two_axes is true. The axis number will wrap around, just like
    # the dclrs array.
    use_axis            => [1, 2],
 
    # Print values on the axes?
    x_plot_values       => 1,
    y_plot_values       => 1,
 
    # Space between axis and text
    axis_space          => 4,
 
    # Do you want bars to be drawn on top of each other, or side by side?
    overwrite           => 0,

# This will replace 'overwrite = 2'. For now, it is hardcoded to set
    # overwrite to 2
    cumulate            => 0,

# Do you want me to correct the width of the graph, so that bars are
    # always drawn with a nice integer number of pixels?
    #
    # The GD::Graph::bars::initialise sub will switch this on.
    # Do not set this to anything else than undef!
    correct_width       => undef,

# XXX The following two need to get better defaults. Maybe computed.
    # Draw the zero axis in the graph in case there are negative values
    zero_axis           =>  0,

# Draw the zero axis, but do not draw the bottom axis, in case
    # box-axis == 0
    # This also moves the x axis labels to the zero axis
    zero_axis_only      =>  0,

# Size of the legend markers
    legend_marker_height    => 8,
    legend_marker_width     => 12,
    legend_spacing          => 4,
    legend_placement        => 'BC',        # '[BR][LCR]'
    lg_cols                 => undef,

# Display the y values above the bar or point in the graph.
    show_values             => undef,
    hide_overlapping_values => 0,
    values_vertical         => undef,   # vertical?
    values_space            => 4,       # extra spacing
    values_format           => undef,   # how to format the value
    
    # Draw the X axis left and the y1 axis at the bottom (y2 at top)
    rotate_chart            => undef,

# CONTRIB Edwin Hildebrand
    # How narrow is a dataset allowed to become before we drop the
    # accents?
    accent_treshold         => 4,

# Format of the numbers on the x and y axis
    y_number_format         => undef,
    y1_number_format        => undef,       # CONTRIB Andrew OBrien
    y2_number_format        => undef,       # CONTRIB Andrew OBrien
    x_number_format         => undef,       # CONTRIB Scott Prahl

# and some attributes without default values
    x_label         => undef,
    y_label         => undef,
    y1_label        => undef,
    y2_label        => undef,
    x_min_value     => undef,
    x_max_value     => undef,
    y_min_value     => undef,
    y1_min_value    => undef,
    y2_min_value    => undef,
    y_max_value     => undef,
    y1_max_value    => undef,
    y2_max_value    => undef,
    y_min_range     => undef,               # CONTRIB Ben Tilly
    y1_min_range     => undef,
    y2_min_range     => undef,

borderclrs      => undef,

# XXX
    # Multiple inheritance (linespoints and mixed) finally bit me. The
    # _has_defaults and set methods can only work correctly when the
    # spot where the defaults are kept are in a mutual parent, which
    # would be this. The odd implementation of SUPER doesn't help

# XXX points
    # The size of the marker to use in the points and linespoints graphs
    # in pixels
    marker_size => 4,

# attributes with no default
    markers => undef,

# XXX lines
    # The width of the line to use in the lines and linespoints graphs
    # in pixels
    line_width      => 1,

# Set the scale of the line types
    line_type_scale => 8,

# Which line types to use
    line_types      => [1],

# Skip undefined values, and don't draw them at all
    skip_undef      => 0,

# XXX bars
    # Spacing between the bars and groups of bars
    bar_width       => undef,
    bar_spacing     => 0,
    bargroup_spacing=> 0,                   # CONTRIB Grant McLean

# cycle through colours per data point, not set
    cycle_clrs      => 0,

# colour of the shadow
    shadowclr       => 'dgray',
    shadow_depth    => 0,

# XXX mixed
    default_type    => 'lines',
    types           => undef,
);

sub _has_default { 
    my $self = shift;
    my $attr = shift || return;
    exists $Defaults{$attr} || $self->SUPER::_has_default($attr);
}

sub initialise
{
    my $self = shift;

$self->SUPER::initialise();

while (my($key, $val) = each %Defaults) 
        { $self->{$key} = $val }

$self->set_x_label_font(GD::gdSmallFont);
    $self->set_y_label_font(GD::gdSmallFont);
    $self->set_x_axis_font(GD::gdTinyFont);
    $self->set_y_axis_font(GD::gdTinyFont);
    $self->set_legend_font(GD::gdTinyFont);
    $self->set_values_font(GD::gdTinyFont);
}

# PUBLIC
sub plot
{
    my $self = shift;
    my $data = shift;

$self->check_data($data)            or return;
    $self->init_graph()                 or return;
    $self->setup_text()                 or return;
    $self->setup_legend();
    $self->setup_coords()               or return;
    $self->draw_text();
    unless (defined $self->{no_axes})
    {
        $self->draw_axes();
        $self->draw_ticks()             or return;
    }
    $self->draw_data()                  or return;
    $self->draw_values()                or return;
    $self->draw_legend();

return $self->{graph}
}

sub set
{
    my $self = shift;
    my %args = @_;

for (keys %args) 
    { 
        /^tick_length$/ and do 
        {
            $self->{x_tick_length} = 
            $self->{y_tick_length} = $args{$_};
            delete $args{$_};
            next;
        };
        /^long_ticks$/ and do 
        {
            $self->{x_long_ticks} = 
            $self->{y_long_ticks} = $args{$_};
            delete $args{$_};
            next;
        };
        /^overwrite$/ and do
        {
            $self->{cumulate} = 1 if $args{$_} == 2;
            $self->{overwrite} = $args{$_};
            delete $args{$_};
            next;
        };
        /^cumulate$/ and do
        {
            $self->{cumulate} = $args{$_};
            # XXX And for now
            $self->{overwrite} = 2 if $args{$_};
            delete $args{$_};
            next;
        };
    }

return $self->SUPER::set(%args);
}

sub setup_text
{
    my $self = shift;

$self->{gdta_x_label}->set(colour => $self->{lci});
    $self->{gdta_y_label}->set(colour => $self->{lci});
    $self->{xlfh} = $self->{gdta_x_label}->get('height');
    $self->{ylfh} = $self->{gdta_y_label}->get('height');

$self->{gdta_x_axis}->set(colour => $self->{alci});
    $self->{gdta_y_axis}->set(colour => $self->{alci});
    $self->{xafh} = $self->{gdta_x_axis}->get('height');
    $self->{yafh} = $self->{gdta_x_axis}->get('height');

$self->{gdta_title}->set(colour => $self->{tci});
    $self->{gdta_title}->set_align('top', 'center');
    $self->{tfh} = $self->{gdta_title}->get('height');

$self->{gdta_legend}->set(colour => $self->{legendci});
    $self->{gdta_legend}->set_align('top', 'left');
    $self->{lgfh} = $self->{gdta_legend}->get('height');

$self->{gdta_values}->set(colour => $self->{valuesci});
    unless ($self->{rotate_chart})
    {
        if ($self->{values_vertical})
        {
            $self->{gdta_values}->set_align('center', 'left');
        }
        else
        {
            $self->{gdta_values}->set_align('bottom', 'center');
        }
    }
    else
    {
        if ($self->{values_vertical})
        {
            $self->{gdta_values}->set_align('top', 'center');
        }
        else
        {
            $self->{gdta_values}->set_align('center', 'left');
        }
    }

return $self;
}

sub set_x_label_font # (fontname)
{
    my $self = shift;
    $self->_set_font('gdta_x_label', @_);
}
sub set_y_label_font # (fontname)
{
    my $self = shift;
    $self->_set_font('gdta_y_label', @_);
}
sub set_x_axis_font # (fontname)
{
    my $self = shift;
    $self->_set_font('gdta_x_axis', @_);
}

sub set_y_axis_font # (fontname)
{
    my $self = shift;
    $self->_set_font('gdta_y_axis', @_);
}

sub set_values_font
{
    my $self = shift;
    $self->_set_font('gdta_values', @_);
}

sub set_legend # List of legend keys
{
    my $self = shift;
    $self->{legend} = [@_];
}

sub set_legend_font # (font name)
{
    my $self = shift;
    $self->_set_font('gdta_legend', @_);
}

sub get_hotspot
{
    my $self = shift;
    my $ds = shift;     # Which data set
    my $np = shift;     # Which data point?

if (defined $np && defined $ds)
    {
        return @{$self->{_hotspots}->[$ds]->[$np]};
    }
    elsif (defined $ds)
    {
        return @{$self->{_hotspots}->[$ds]};
    }
    else
    {
        return @{$self->{_hotspots}};
    }
}

sub _set_feature_coords
{
    my $self = shift;
    my $feature = shift;
    my $type = shift;
    $self->{_feat_coords}->{$feature} = [ $type, @_ ];
}

sub _set_text_feature_coords
{
    my $self = shift;
    my $feature = shift;
    $self->_set_feature_coords($feature, "rect", @_[0,1,4,5]);
}

sub get_feature_coordinates
{
    my $self = shift;
    my $feature = shift;
    if ($feature)
    {
        $self->{_feat_coords}->{$feature};
    }
    else
    {
        $self->{_feat_coords};
    }
}

# PRIVATE

# inherit check_data from GD::Graph

#
# calculate the bottom of the bounding box for the graph
#
sub setup_bottom_boundary
{
    my $self = shift;
    $self->{bottom} = $self->{height} - $self->{b_margin} - 1;
    if (! $self->{rotate_chart})
    {
        # X label
        $self->{bottom} -= $self->{xlfh} + $self->{text_space}
            if $self->{xlfh};
        # X axis tick labels
        $self->{bottom} -= $self->{x_label_height} + $self->{axis_space}
            if $self->{xafh};
    }
    else
    {
        # Y1 label
        $self->{bottom} -= $self->{ylfh} + $self->{text_space}
            if $self->{y1_label};
        # Y1 axis labels
        $self->{bottom} -= $self->{y_label_height}[1] + $self->{axis_space}
            if $self->{y_label_height}[1];
    }
}
#
# Calculate the top of the bounding box for the graph
#
sub setup_top_boundary
{
    my $self = shift;

$self->{top} = $self->{t_margin};
    # Chart title
    $self->{top} += $self->{tfh} + $self->{text_space} if $self->{tfh};
    if (! $self->{rotate_chart})
    {
        # Make sure the text for the y axis tick markers fits on the canvas
        $self->{top} = $self->{yafh}/2 if $self->{top} == 0;
    }
    else
    {
        if ($self->{two_axes})
        {
            # Y2 label
            $self->{top} += $self->{ylfh} + $self->{text_space}
                if $self->{y2_label};
            # Y2 axis labels
            $self->{top} += $self->{y_label_height}[2] + $self->{axis_space}
                if $self->{y_label_height}[2];
        }
    }
}
#
# calculate the left of the bounding box for the graph
#
sub setup_left_boundary
{
    my $self = shift;

$self->{left} = $self->{l_margin};
    if (! $self->{rotate_chart})
    {
        # Y1 label
        $self->{left} += $self->{ylfh} + $self->{text_space}
            if $self->{y1_label};
        # Y1 axis labels
        $self->{left} += $self->{y_label_len}[1] + $self->{axis_space}
            if $self->{y_label_len}[1];
    }
    else
    {
        # X label
        $self->{left} += $self->{xlfh} + $self->{text_space}
            if $self->{x_label};
        # X axis labels
        $self->{left} += $self->{x_label_width} + $self->{axis_space}
            if $self->{x_label_width};
    }
}
#
# calculate the right of the bounding box for the graph
#
sub setup_right_boundary
{
    my $self = shift;
    $self->{right} = $self->{width} - $self->{r_margin} - 1;

if (! $self->{rotate_chart})
    {
        if ($self->{two_axes})
        {
            # Y2 label
            $self->{right} -= $self->{ylfh} + $self->{text_space}
                if $self->{y2_label};
            # Y2 axis label
            $self->{right} -= $self->{y_label_len}[2] + $self->{axis_space}
                if $self->{y_label_len}[2];
        }
    }
    else
    {
        # Adjust right margin to allow last label of y axes. Only do
        # this when the right margin doesn't have enough space
        # already.
        #
        # TODO Don't assume rightmost label is the same as the
        # longest label (stored in y_label_len) The worst that can
        # happen now is that we reserve too much space.
    
        my $max_len = $self->{y_label_len}[1];
        if ($self->{two_axes})
        {
            $max_len = $self->{y_label_len}[2] if 
            $self->{y_label_len}[2] > $max_len;
        }
        $max_len = int ($max_len/2);
    
        if ($self->{right} + $max_len >= $self->{width} - $self->{r_margin})
        {
            $self->{right} -= $max_len;
        }
    }
}

sub _setup_boundaries
{
    my $self = shift;

$self->setup_bottom_boundary();
    $self->setup_top_boundary();
    $self->setup_left_boundary();
    $self->setup_right_boundary();

if ($self->correct_width && !$self->{x_tick_number})
    {
        if (! $self->{rotate_chart})
        {
            # Make sure we have a nice integer number of pixels
            $self->{r_margin} += ($self->{right} - $self->{left}) %
                ($self->{_data}->num_points + 1);
            
            $self->setup_right_boundary();
        }
        else
        {
            # Make sure we have a nice integer number of pixels
            $self->{b_margin} += ($self->{bottom} - $self->{top}) %
                ($self->{_data}->num_points + 1);
            
            $self->setup_bottom_boundary();
        }
    }

return $self->_set_error('Vertical size too small')
        if $self->{bottom} <= $self->{top};
    return $self->_set_error('Horizontal size too small')   
        if $self->{right} <= $self->{left};

return $self;
}

# This method should return 1 if the width of the graph needs to be
# corrected to whole integers, and 0 if not. The default behaviour is to
# not correct the width. Individual classes should override this by
# setting the $self->{correct_width} attribute in their initialise
# method. Only in complex cases (see mixed.pm) should this method be
# overridden
sub correct_width { $_[0]->{correct_width} }

sub setup_x_step_size_v
{
    my $s = shift;

# calculate the step size for x data
    # CONTRIB Changes by Scott Prahl
    if (defined $s->{x_tick_number})
    {
        my $delta = ($s->{right} - $s->{left})/($s->{x_max} - $s->{x_min});
        # 'True' numerical X axis addition # From: Gary Deschaines
        if (defined($s->{x_min_value}) && defined($s->{x_max_value}))
        {
            $s->{x_offset} = $s->{left};
            $s->{x_step} = $delta;
        }
        else
        {
            $s->{x_offset} = 
                ($s->{true_x_min} - $s->{x_min}) * $delta + $s->{left};
            $s->{x_step} = 
                ($s->{true_x_max} - $s->{true_x_min}) * 
                $delta/($s->{_data}->num_points - 1);
        }
    }
    else
    {
        $s->{x_step} = ($s->{right} - $s->{left})/($s->{_data}->num_points + 1);
        $s->{x_offset} = $s->{left};
    }
}

sub setup_x_step_size_h
{
    my $s = shift;

# calculate the step size for x data
    # CONTRIB Changes by Scott Prahl
    if (defined $s->{x_tick_number})
    {
        my $delta = ($s->{bottom} - $s->{top})/($s->{x_max} - $s->{x_min});
        # 'True' numerical X axis addition # From: Gary Deschaines
        if (defined($s->{x_min_value}) && defined($s->{x_max_value}))
        {
            $s->{x_offset} = $s->{top};
            $s->{x_step} = $delta;
        }
        else
        {
            $s->{x_offset} = 
                ($s->{true_x_min} - $s->{x_min}) * $delta + $s->{top};
            $s->{x_step} = 
                ($s->{true_x_max} - $s->{true_x_min}) * 
                $delta/($s->{_data}->num_points - 1);
        }
    }
    else
    {
        $s->{x_step} = ($s->{bottom} - $s->{top})/($s->{_data}->num_points + 1);
        $s->{x_offset} = $s->{top};
    }
}

sub setup_coords
{
    my $s = shift;

# Do some sanity checks
    $s->{two_axes} = 0 if $s->{_data}->num_sets < 2 || $s->{two_axes} < 0;
    $s->{two_axes} = 1 if $s->{two_axes} > 1;

delete $s->{y_label2} unless $s->{two_axes};

# Set some heights for text
    $s->{tfh}  = 0 unless $s->{title};
    $s->{xlfh} = 0 unless $s->{x_label};

# Make sure the y1 axis has a label if there is one set for y in
    # general
    $s->{y1_label} = $s->{y_label} if !$s->{y1_label} && $s->{y_label};

# Set axis tick text heights and widths to 0 if they don't need to
    # be plotted.
    $s->{xafh} = 0, $s->{xafw} = 0 unless $s->{x_plot_values}; 
    $s->{yafh} = 0, $s->{yafw} = 0 unless $s->{y_plot_values};

# Calculate minima and maxima for the axes
    $s->set_max_min() or return;

# Create the labels for the axes, and calculate the max length
    $s->create_y_labels();
    $s->create_x_labels(); # CONTRIB Scott Prahl

# Calculate the boundaries of the chart
    $s->_setup_boundaries() or return;

# CONTRIB Scott Prahl
    # make sure that we can generate valid x tick marks
    undef($s->{x_tick_number}) if $s->{_data}->num_points < 3;
    undef($s->{x_tick_number}) if
        !defined $s->{x_max} || 
        !defined $s->{x_min} || 
        $s->{x_max} == $s->{x_min};

$s->{rotate_chart} ? $s->setup_x_step_size_h() :
                         $s->setup_x_step_size_v();

# get the zero axis level
    my ($zl, $zb) = $s->val_to_pixel(0, 0, 1);
    my ($min,$val,$max) = $s->{rotate_chart} 
        ? ( $s->{left}, $zl, $s->{right} )
        : ( $s->{top}, $zb, $s->{bottom} );
    
    $s->{zeropoint} = $min > $val ? $min : $max < $val ? $max : $val;

# More sanity checks
    $s->{x_label_skip} = 1      if $s->{x_label_skip}  < 1;
    $s->{y_label_skip} = 1      if $s->{y_label_skip}  < 1;
    $s->{y_tick_number} = 1     if $s->{y_tick_number} < 1;

return $s;
}

sub create_y_labels
{
    my $self = shift;

# XXX This should really be y_label_width
    $self->{y_label_len}[$_]    = 0 for 1, 2;
    $self->{y_label_height}[$_] = 0 for 1, 2;

for my $t (0 .. $self->{y_tick_number})
    {
        # XXX Ugh, why did I ever do it this way? How bloody obscure.
        for my $axis (1 .. ($self->{two_axes} + 1))
        {
            my $label = $self->{y_min}[$axis] +
                $t * ($self->{y_max}[$axis] - $self->{y_min}[$axis]) /
                $self->{y_tick_number};
            
            $self->{y_values}[$axis][$t] = $label;

if (my ($fmt) = grep defined, map($self->{"y${_}_number_format"},$axis,'') )
            {
                $label = ref $fmt eq 'CODE' ?
                    $fmt->($label) :
                    sprintf($fmt, $label);
            }
            
            $self->{gdta_y_axis}->set_text($label);
            my $len = $self->{gdta_y_axis}->get('width');

$self->{y_labels}[$axis][$t] = $label;

# TODO Allow vertical y labels
            $self->{y_label_len}[$axis] = $len 
                if $len > $self->{y_label_len}[$axis];
            $self->{y_label_height}[$axis] = $self->{yafh};
        }
    }
}

sub get_x_axis_label_length
{
    my $self = shift;

my @values = $self->{x_tick_number} ? 
        @{$self->{x_values}} : 
        $self->{_data}->x_values;

my $maxlen = 0;
    foreach my $label (@values)
    {
        $self->{gdta_x_axis}->set_text($label);
        my $len = $self->{gdta_x_axis}->get('width');
        $maxlen = $len if $maxlen < $len;
    }

return $maxlen;
}

# CONTRIB Scott Prahl
sub create_x_labels
{
    my $self = shift;
    my $maxlen = 0;

$self->{x_label_height} = 0;
    $self->{x_label_width} = 0;

if (defined $self->{x_tick_number})
    {
        # We want to emulate numerical x axes
        foreach my $t (0..$self->{x_tick_number})
        {
            my $label =
                $self->{x_min} +
                $t * ($self->{x_max} - $self->{x_min})/$self->{x_tick_number};

$self->{x_values}[$t] = $label;

if (defined $self->{x_number_format})
            {
                $label = ref $self->{x_number_format} eq 'CODE' ?
                    &{$self->{x_number_format}}($label) :
                    sprintf($self->{x_number_format}, $label);
            }

$self->{gdta_x_label}->set_text($label);
            my $len = $self->{gdta_x_label}->get('width');

$self->{x_labels}[$t] = $label;
            $maxlen = $len 
                if $len > $self->{x_label_height};
        }
    }
    else
    {
        $maxlen = $self->get_x_axis_label_length;
    }

$self->{x_label_height} = $self->{x_labels_vertical} ?
        $maxlen : $self->{xafh};
    $self->{x_label_width} = $self->{x_labels_vertical} ?
        $self->{xafh} : $maxlen;
}

#
# The drawing of labels for the axes. This is split up in the four
# positions a label can appear in, depending on a few settings. These
# settings are all dealt with in the draw_x_labels and draw_y_labels
# subroutines, which in turn call the appropriate directional label
# drawer
#
sub draw_left_label
{
    my ($self, $label, $align) = @_;

$label->set_align('top', 'left');
    my $tx = $self->{l_margin};
    my $ty = $self->{bottom} - $align * ($self->{bottom} - $self->{top}) + 
        $align * $label->get('width');
    $label->draw($tx, $ty, PI/2);
}

sub draw_bottom_label
{
    my ($self, $label, $align) = @_;

$label->set_align('bottom', 'left');
    my $tx = $self->{left} + $align * ($self->{right} - $self->{left}) - 
        $align * $label->get('width');
    my $ty = $self->{height} - $self->{b_margin};
    $label->draw($tx, $ty, 0);
}

sub draw_top_label
{
    my ($self, $label, $align) = @_;

$label->set_align('top', 'left');
    my $tx = $self->{left} + $align * ($self->{right} - $self->{left}) - 
        $align * $label->get('width');
    my $ty = $self->{t_margin};
    $ty += $self->{tfh} + $self->{text_space} if $self->{tfh};
    $label->draw($tx, $ty, 0);
}

sub draw_right_label
{
    my ($self, $label, $align) = @_;

$label->set_align('bottom', 'left');
    my $tx = $self->{width} - $self->{r_margin};
    my $ty = $self->{bottom} - $align * ($self->{bottom} - $self->{top}) + 
        $align * $label->get('width');
    $label->draw($tx, $ty, PI/2);
}

sub draw_x_label
{
    my $self = shift;
    my ($tx, $ty, $a);

my @coords; # coordinates of the label drawn

return unless $self->{x_label};

$self->{gdta_x_label}->set_text($self->{x_label});
    if ($self->{rotate_chart})
    {
        @coords = $self->draw_left_label($self->{gdta_x_label}, 
                               $self->{x_label_position});
    }
    else
    {
        @coords = $self->draw_bottom_label($self->{gdta_x_label}, 
                               $self->{x_label_position});
    }
    $self->_set_text_feature_coords("x_label", @coords);
}

sub draw_y_labels
{
    my $self = shift;

my @coords; # coordinates of the labels drawn

if (defined $self->{y1_label}) 
    {
        $self->{gdta_y_label}->set_text($self->{y1_label});
        if ($self->{rotate_chart})
        {
            @coords = $self->draw_bottom_label($self->{gdta_y_label}, 
                                     $self->{y_label_position});
        }
        else
        {
            @coords = $self->draw_left_label($self->{gdta_y_label}, 
                                   $self->{y_label_position});
        }
        $self->_set_text_feature_coords("y1_label", @coords);
        $self->_set_text_feature_coords("y_label", @coords);
    }
    if ( $self->{two_axes} && defined $self->{y2_label} ) 
    {
        $self->{gdta_y_label}->set_text($self->{y2_label});
        if ($self->{rotate_chart})
        {
            @coords = $self->draw_top_label($self->{gdta_y_label}, 
                                  $self->{y_label_position});
        }
        else
        {
            @coords = $self->draw_right_label($self->{gdta_y_label}, 
                                    $self->{y_label_position});
        }
        $self->_set_text_feature_coords("y2_label", @coords);
    }
}

sub draw_text
{
    my $self = shift;

if ($self->{title})
    {
        my $xc = $self->{left} + ($self->{right} - $self->{left})/2;
        $self->{gdta_title}->set_align('top', 'center');
        $self->{gdta_title}->set_text($self->{title});
        my @coords = $self->{gdta_title}->draw($xc, $self->{t_margin});
        $self->_set_text_feature_coords("title", @coords);
    }

$self->draw_x_label();
    $self->draw_y_labels();
}

sub draw_axes
{
    my $self = shift;

my ($l, $r, $b, $t) = 
        ( $self->{left}, $self->{right}, $self->{bottom}, $self->{top} );
    
    # Sanity check for zero_axis and zero_axis_only
    unless ($self->{y_min}[1] < 0 && $self->{y_max}[1] > 0)
    {
        $self->{zero_axis} = 0;
        $self->{zero_axis_only} = 0;
    }

if ( $self->{box_axis} ) 
    {
        $self->{graph}->filledRectangle($l+1, $t+1, $r-1, $b-1, $self->{boxci})
            if $self->{boxci};

$self->{graph}->rectangle($l, $t, $r, $b, $self->{fgci});
    }
    else
    {
        $self->{graph}->line($l, $t, $l, $b, $self->{fgci});
        $self->{graph}->line($l, $b, $r, $b, $self->{fgci}) 
            unless ($self->{zero_axis_only});
        $self->{graph}->line($r, $b, $r, $t, $self->{fgci}) 
            if ($self->{two_axes});
    }

if ($self->{zero_axis} or $self->{zero_axis_only})
    {
        my ($x, $y) = $self->val_to_pixel(0, 0, 1);
        $self->{graph}->line($l, $y, $r, $y, $self->{fgci});
    }

$self->_set_feature_coords("axes", "rect", $l, $b, $r, $t);
}

#
# Ticks and values for y axes
#
sub draw_y_ticks_h
{
    my $self = shift;

for my $t (0 .. $self->{y_tick_number}) 
    {
        for my $axis (1 .. ($self->{two_axes} + 1)) 
        {
            my $value = $self->{y_values}[$axis][$t];
            my $label = $self->{y_labels}[$axis][$t];
            
            my ($x, $y) = $self->val_to_pixel(0, $value, -$axis);
            $y = ($axis == 1) ? $self->{bottom} : $self->{top};
            
            if ($self->{y_long_ticks}) 
            {
                $self->{graph}->line( 
                    $x, $self->{bottom}, 
                    $x, $self->{top}, 
                    $self->{fgci} 
                ) unless ($axis-1);
            } 
            else 
            {
                $self->{graph}->line( 
                    $x, $y, 
                    $x, $y  - $self->{y_tick_length}, 
                    $self->{fgci} 
                );
            }

next 
                if $t % ($self->{y_label_skip}) || ! $self->{y_plot_values};

$self->{gdta_y_axis}->set_text($label);
            if ($axis == 1)
            {
                $self->{gdta_y_axis}->set_align('top', 'center');
                $y += $self->{axis_space};
            }
            else
            {
                $self->{gdta_y_axis}->set_align('bottom', 'center');
                $y -= $self->{axis_space};
            }
            $self->{gdta_y_axis}->draw($x, $y);
        }
    }

return $self;
}

sub draw_y_ticks_v
{
    my $self = shift;

for my $t (0 .. $self->{y_tick_number}) 
    {
        # XXX Ugh, why did I ever do it this way? How bloody obscure.
        for my $axis (1 .. ($self->{two_axes} + 1)) 
        {
            my $value = $self->{y_values}[$axis][$t];
            my $label = $self->{y_labels}[$axis][$t];
            
            my ($x, $y) = $self->val_to_pixel(0, $value, -$axis);
            $x = ($axis == 1) ? $self->{left} : $self->{right};

if ($self->{y_long_ticks}) 
            {
                $self->{graph}->line( 
                    $x, $y, 
                    $x + $self->{right} - $self->{left}, $y, 
                    $self->{fgci} 
                ) unless ($axis-1);
            } 
            else 
            {
                $self->{graph}->line( 
                    $x, $y, 
                    $x + (3 - 2 * $axis) * $self->{y_tick_length}, $y, 
                    $self->{fgci} 
                );
            }

next 
                if $t % ($self->{y_label_skip}) || ! $self->{y_plot_values};

$self->{gdta_y_axis}->set_text($label);
            if ($axis == 1)
            {
                $self->{gdta_y_axis}->set_align('center', 'right');
                $x -= $self->{axis_space};
            }
            else
            {
                $self->{gdta_y_axis}->set_align('center', 'left');
                $x += $self->{axis_space};
            }
            $self->{gdta_y_axis}->draw($x, $y);
        }
    }

return $self;
}

sub draw_y_ticks
{
    #TODO Clean this up!
    $_[0]->{rotate_chart} ? goto &draw_y_ticks_h : goto &draw_y_ticks_v;
}

#
# Ticks and values for x axes
#
sub draw_x_ticks_h
{
    my $self = shift;

for (my $i = 0; $i < $self->{_data}->num_points; $i++) 
    {
        my ($x, $y) = $self->val_to_pixel($i + 1, 0, 1);

$x = $self->{left} unless $self->{zero_axis_only};

# Skip unwanted axis ticks
        next unless 
	    $self->{x_all_ticks} or 
	    ($i - $self->{x_tick_offset}) % $self->{x_label_skip} == 0 or
	    $i == $self->{_data}->num_points - 1 && !$self->{x_last_label_skip};

# Draw the tick on the X axis
        if ($self->{x_ticks})
        {
            if ($self->{x_long_ticks})
            {
                $self->{graph}->line($self->{left}, $y, $self->{right}, $y, 
                    $self->{fgci});
            }
            else
            {
                $self->{graph}->line( $x, $y, $x + $self->{x_tick_length}, $y,
                    $self->{fgci});
            }
        }

# Skip unwanted axis tick labels.
        next unless 
	    ($i - $self->{x_tick_offset}) % $self->{x_label_skip} == 0 or
	    $i == $self->{_data}->num_points - 1 && !$self->{x_last_label_skip};

my $text = $self->{_data}->get_x($i);
        if (defined $text)
        {
            $self->{gdta_x_axis}->set_text($text);

# Draw the tick label
            my $angle = 0;
            if ($self->{x_labels_vertical})
            {
                $self->{gdta_x_axis}->set_align('bottom', 'center');
                $angle = PI/2;
            }
            else
            {
                $self->{gdta_x_axis}->set_align('center', 'right');
            }
            $self->{gdta_x_axis}->draw($x - $self->{axis_space}, $y, $angle);
        } 
        elsif ($INC{'warnings.pm'} && warnings::enabled('uninitialized') || $^W ) 
        {
            carp("Uninitialized label value at index $i");
        }
    }

return $self;
}

sub draw_x_ticks_v
{
    my $self = shift;

for (my $i = 0; $i < $self->{_data}->num_points; $i++) 
    {
        my ($x, $y) = $self->val_to_pixel($i + 1, 0, 1);

$y = $self->{bottom} unless $self->{zero_axis_only};

if ($self->{x_ticks})
        {
            if ($self->{x_long_ticks})
            {
                $self->{graph}->line($x, $self->{bottom}, $x, $self->{top},
                    $self->{fgci});
            }
            else
            {
                $self->{graph}->line($x, $y, $x, $y - $self->{x_tick_length},
                    $self->{fgci});
            }
        }

# Skip unwanted axis tick labels.
        next unless 
	    ($i - $self->{x_tick_offset}) % $self->{x_label_skip} == 0 or
	    $i == $self->{_data}->num_points - 1 && !$self->{x_last_label_skip};

my $text = $self->{_data}->get_x($i);
        if (defined $text)
        {
            $self->{gdta_x_axis}->set_text($text);

my $angle = 0;
            if ($self->{x_labels_vertical})
            {
                $self->{gdta_x_axis}->set_align('center', 'right');
                $angle = PI/2;
            }
            else
            {
                $self->{gdta_x_axis}->set_align('top', 'center');
            }
            $self->{gdta_x_axis}->draw($x, $y + $self->{axis_space}, $angle);
        } 
        elsif ($INC{'warnings.pm'} && warnings::enabled('uninitialized') || $^W ) 
        {
            carp("Uninitialized label value at index $i");
        }
    }

return $self;
}

sub draw_x_ticks
{
    #TODO Clean this up!
    $_[0]->{rotate_chart} ? goto &draw_x_ticks_h : goto &draw_x_ticks_v;
}

# CONTRIB Scott Prahl
# Assume x array contains equally spaced x-values
# and generate an appropriate axis
#
####
# 'True' numerical X axis addition 
# From: Gary Deschaines
#
# These modification to draw_x_ticks_number pass x-tick values to the
# val_to_pixel subroutine instead of x-tick indices when ture numerical
# x-axis mode is detected.  Also, x_tick_offset and x_label_skip are
# processed differently when true numerical x-axis mode is detected to
# allow labeled major x-tick marks and un-labeled minor x-tick marks.
#
# For example:
#
#      x_tick_number =>  14,
#      x_ticks       =>   1,
#      x_long_ticks  =>   1,
#      x_tick_length =>  -4,
#      x_min_value   => 100,
#      x_max_value   => 800,
#      x_tick_offset =>   2,
#      x_label_skip  =>   2,
#
#
#      ~         ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~         ~
#      |         |    |    |    |    |    |    |    |    |    |    |         |
#   1 -|         |    |    |    |    |    |    |    |    |    |    |         |
#      |         |    |    |    |    |    |    |    |    |    |    |         |
#   0 _|_________|____|____|____|____|____|____|____|____|____|____|_________|
#                |    |    |    |    |    |    |    |    |    |    |
#               200       300       400       500       600       700
sub draw_x_ticks_number
{
    my $self = shift;

for my $i (0 .. $self->{x_tick_number})
    {
        my ($value, $x, $y);

if (defined($self->{x_min_value}) && defined($self->{x_max_value}))
        {
            next if ($i - $self->{x_tick_offset}) < 0;
            next if ($i + $self->{x_tick_offset}) > $self->{x_tick_number};
            $value = $self->{x_values}[$i];
            ($x, $y) = $self->val_to_pixel($value, 0, 1);
        }
        else
        {
            $value = ($self->{_data}->num_points - 1)
                        * ($self->{x_values}[$i] - $self->{true_x_min})
                        / ($self->{true_x_max} - $self->{true_x_min});
            ($x, $y) = $self->val_to_pixel($value + 1, 0, 1);
        }

$y = $self->{bottom} unless $self->{zero_axis_only};

if ($self->{x_ticks})
        {
            if ($self->{x_long_ticks})
            {
                # XXX This mod needs to be done everywhere ticks are
                # drawn
                if ( $self->{x_tick_length} >= 0 ) 
                {
                    $self->{graph}->line($x, $self->{bottom}, 
                        $x, $self->{top}, $self->{fgci});
                } 
                else 
                {
                    $self->{graph}->line(
                        $x, $self->{bottom} - $self->{x_tick_length}, 
                        $x, $self->{top}, $self->{fgci});
                }
            }
            else
            {
                $self->{graph}->line($x, $y, 
                    $x, $y - $self->{x_tick_length}, $self->{fgci} );
            }
        }

# If we have to skip labels, we'll do it here.
        # Make sure to always draw the last one.
        next if $i % $self->{x_label_skip} and
		    $i != $self->{_data}->num_points - 1;

$self->{gdta_x_axis}->set_text($self->{x_labels}[$i]);

if ($self->{x_labels_vertical})
        {
            $self->{gdta_x_axis}->set_align('center', 'right');
            my $yt = $y + $self->{text_space}/2;
            $self->{gdta_x_axis}->draw($x, $yt, PI/2);
        }
        else
        {
            $self->{gdta_x_axis}->set_align('top', 'center');
            my $yt = $y + $self->{text_space}/2;
            $self->{gdta_x_axis}->draw($x, $yt);
        }
    }

return $self;
}

sub draw_ticks
{
    my $self = shift;

$self->draw_y_ticks() or return;

return $self 
        unless $self->{x_plot_values};

if (defined $self->{x_tick_number})
    {
        $self->draw_x_ticks_number() or return;
    }
    else
    {
        $self->draw_x_ticks() or return;
    }

return $self;
}

sub draw_data
{
    my $self = shift;

# Calculate bar_spacing from bar_width
    if ($self->{bar_width})
    {
        my $chart_width = !$self->{rotate_chart} ? 
            $self->{right} - $self->{left} :
            $self->{bottom} - $self->{top};
        my $n_bars = $self->{_data}->num_points;
        my $n_sets = $self->{_data}->num_sets;
        my $bar_space = $chart_width/($n_bars + 1) /
            ($self->{overwrite} ? 1 : $n_sets);
        $self->{bar_spacing} = $bar_space - $self->{bar_width};
        $self->{bar_spacing} = 0 if $self->{bar_spacing} < 0;
    }

# XXX is this comment still pertinent?
    # The drawing of 'cumulated' sets needs to be done in reverse,
    # for area and bar charts. This is mainly because of backward
    # compatibility

for (my $dsn = 1; $dsn <= $self->{_data}->num_sets; $dsn++)
    {
        $self->draw_data_set($dsn) or return;
    }

return $self
}

#
# Draw the values of the data point with the bars, lines or markers
sub draw_values
{
    my $self = shift;
    
    return $self unless $self->{show_values};
    
    my $text_angle = $self->{values_vertical} ? PI/2 : 0;
    my (@bars,@others);

if ($self->isa('GD::Graph::mixed') ) {
        # 1-indexed, like data-sets themselves
        my @types = $self->types;
        push @{'bars' eq $types[$_ - 1] ? \@bars : \@others}, $_ for 1 .. @types;
        $self->GD::Graph::bars::draw_values(@bars) if @bars;
    } else { 
        @others = 1 .. $self->{_data}->num_sets;
    }

foreach my $dsn ( @others )
    {
        my @values = $self->{_data}->y_values($dsn) or
                return $self->_set_error("Impossible illegal data set: $dsn",
                    $self->{_data}->error);
        my @display = $self->{show_values}->y_values($dsn) or next;

for (my $i = 0; $i < @values; $i++)
        {
            next unless defined $display[$i];
            my ($xp, $yp);
            if (defined($self->{x_min_value}) && defined($self->{x_max_value}))
            {
                ($xp, $yp) = $self->val_to_pixel(
                    $self->{_data}->get_x($i), $values[$i], $dsn);
            }
            else    
            {
                ($xp, $yp) = $self->val_to_pixel($i+1, $values[$i], $dsn);
            }
            $yp -= $self->{values_space};

my $value = $display[$i];
            if (defined $self->{values_format})
            {
                $value = ref $self->{values_format} eq 'CODE' ?
                    &{$self->{values_format}}($value) :
                    sprintf($self->{values_format}, $value);
            }

$self->{gdta_values}->set_text($value);
            $self->{gdta_values}->draw($xp, $yp, $text_angle);
        }
    }

return $self
}

#
# draw_data_set is in sub classes
#
sub draw_data_set
{
    # ABSTRACT
    my $self = shift;
    $self->die_abstract( "sub draw_data missing, ")
}

#
# This method corrects the minimum and maximum y values for chart
# types that need to always include a zero point.
# This is supposed to be called before the methods that pick
# good-looking values.
#
# Input: current minimum and maximum.
# Output: new minimum and maximum.
#
sub _correct_y_min_max
{
    my $self = shift;
    my ($min, $max) = @_;

# Make sure bars and area always have a zero offset
    # Only bars and areas need 
    return ($min, $max)
        unless $self->isa("GD::Graph::bars") or $self->isa("GD::Graph::area");

# If either $min or $max are 0, we can return
    return ($min, $max) if $max == 0 or $min == 0;

# If $min and $max on opposite end of zero axis, no work needed
    return ($min, $max) unless $min/$max > 0;

if ($min > 0)
    {
        $min = 0;
    }
    else
    {
        $max = 0;
    }

return ($min, $max);
}

#
# Figure out the maximum values for the vertical exes, and calculate
# a more or less sensible number for the tops.
#
sub set_max_min
{
    my $self = shift;

# XXX fix to calculate min and max for each data set
    # independently, and store in an array. Then, based on use_axis,
    # pick the minimust and maximust for each axis, and use those.

# First, calculate some decent values
    if ( $self->{two_axes} ) 
    {
        my $min_range_1 = defined($self->{y1_min_range})
                ? $self->{y1_min_range}
                : $self->{y_min_range};
        my $min_range_2 = defined($self->{y2_min_range})
                ? $self->{y2_min_range}
                : $self->{y_min_range};

my(@y_min, @y_max);
        for my $nd (1 .. $self->{_data}->num_sets)
        {
            my $axis = $self->{use_axis}->[$nd - 1];
            my($y_min, $y_max) = $self->{_data}->get_min_max_y($nd);
            if (!defined $y_min[$axis] || $y_min[$axis] > $y_min)
            {
                $y_min[$axis] = $y_min;
            }
            if (!defined $y_max[$axis] || $y_max[$axis] < $y_max)
            {
                $y_max[$axis] = $y_max;
            }
        }

(
            $self->{y_min}[1], $self->{y_max}[1],
            $self->{y_min}[2], $self->{y_max}[2],
            $self->{y_tick_number}
        ) = _best_dual_ends(
            $self->_correct_y_min_max($y_min[1], $y_max[1]),
              $min_range_1,
            $self->_correct_y_min_max($y_min[2], $y_max[2]),
              $min_range_2,
            $self->{y_tick_number}
        );
    } 
    else 
    {
        my ($y_min, $y_max);
        if ($self->{cumulate})
        {
            my $data_set = $self->{_data}->copy();
            $data_set->cumulate;
            ($y_min, $y_max) = $data_set->get_min_max_y($data_set->num_sets);
        }
        else
        {
            ($y_min, $y_max) = $self->{_data}->get_min_max_y_all;
        }
        ($y_min, $y_max) = $self->_correct_y_min_max($y_min, $y_max);
        ($self->{y_min}[1], $self->{y_max}[1], $self->{y_tick_number}) =
            _best_ends($y_min, $y_max, @$self{'y_tick_number','y_min_range'});
    }

if (defined($self->{x_tick_number}))
    {
        if (defined($self->{x_min_value}) && defined($self->{x_max_value}))
        {
            $self->{true_x_min} = $self->{x_min_value};
            $self->{true_x_max} = $self->{x_max_value};
        }
        else
        {
            ($self->{true_x_min}, $self->{true_x_max}) = 
                $self->{_data}->get_min_max_x;
        }
        ($self->{x_min}, $self->{x_max}, $self->{x_tick_number}) =
            _best_ends($self->{true_x_min}, $self->{true_x_max},
                    @$self{'x_tick_number','x_min_range'});
    }

# Overwrite these with any user supplied ones
    $self->{y_min}[1] = $self->{y_min_value}  if defined $self->{y_min_value};
    $self->{y_min}[2] = $self->{y_min_value}  if defined $self->{y_min_value};

$self->{y_max}[1] = $self->{y_max_value}  if defined $self->{y_max_value};
    $self->{y_max}[2] = $self->{y_max_value}  if defined $self->{y_max_value};

$self->{y_min}[1] = $self->{y1_min_value} if defined $self->{y1_min_value};
    $self->{y_max}[1] = $self->{y1_max_value} if defined $self->{y1_max_value};

$self->{y_min}[2] = $self->{y2_min_value} if defined $self->{y2_min_value};
    $self->{y_max}[2] = $self->{y2_max_value} if defined $self->{y2_max_value};

$self->{x_min}    = $self->{x_min_value}  if defined $self->{x_min_value};
    $self->{x_max}    = $self->{x_max_value}  if defined $self->{x_max_value};

if (
        $self->{two_axes} && !defined $self->{y1_min_value} && !defined $self->{y2_min_value}
        && !defined $self->{y1_max_value} && !defined $self->{y2_max_value}
    )
    {
        # If we have two axes, we need to make sure that the zero is at
        # the same spot.
        # And we need to change the number of ticks on the axes

my $l_range = $self->{y_max}[1] - $self->{y_min}[1];
        my $r_range = $self->{y_max}[2] - $self->{y_min}[2];

my $l_top = $self->{y_max}[1]/$l_range;
        my $r_top = $self->{y_max}[2]/$r_range;
        my $l_bot = $self->{y_min}[1]/$l_range;
        my $r_bot = $self->{y_min}[2]/$r_range;

if ($l_top > $r_top)
        {
            $self->{y_max}[2] = $l_top * $r_range;
            $self->{y_min}[1] = $r_bot * $l_range;
            $self->{y_tick_number} *= 1 + abs $r_bot - $l_bot;
        }
        else
        {
            $self->{y_max}[1] = $r_top * $l_range;
            $self->{y_min}[2] = $l_bot * $r_range;
            $self->{y_tick_number} *= 1 + abs $r_top - $l_top;
        }
    }

# Check to see if we have sensible values
    if ($self->{two_axes}) 
    {
        for my $i (1 .. $self->{_data}->num_sets)
        {
            my ($min, $max) = $self->{_data}->get_min_max_y($i);
            return $self->_set_error("Minimum for y" . $i . " too large")
                if $self->{y_min}[$self->{use_axis}[$i-1]] > $min;
            return $self->_set_error("Maximum for y" . $i . " too small")
                if $self->{y_max}[$self->{use_axis}[$i-1]] < $max;
        }
    }

return $self;
}

# CONTRIB Scott Prahl
#
# Calculate best endpoints and number of intervals for an axis and
# returns ($nice_min, $nice_max, $n), where $n is the number of
# intervals and
#
#    $nice_min <= $min < $max <= $nice_max
#
# Usage:
#       ($nmin,$nmax,$nint) = _best_ends(247, 508);
#       ($nmin,$nmax) = _best_ends(247, 508, 5); 
#           use 5 intervals
#       ($nmin,$nmax,$nint) = _best_ends(247, 508, [4..7]);   
#           best of 4,5,6,7 intervals
#       ($nmin,$nmax,$nint) = _best_ends(247, 508, 'auto');
#           best of 3,4,5,6 intervals
#       ($nmin,$nmax,$nint) = _best_ends(247, 508, [2..5]);
#           best of 2,3,4,5 intervals
sub _best_ends 
{
    my ($min, $max, $n_ref, $min_range) = @_;

# Adjust for the min range if need be
    ($min, $max) = _fit_vals_range($min, $max, $min_range);

my ($best_min, $best_max, $best_num) = ($min, $max, 1);

# Check that min and max are not the same, and not 0
    ($min, $max) = ($min) ? ($min * 0.5, $min * 1.5) : (-1,1)
        if ($max == $min);
    
    # mgjv - Sometimes, for odd values, and only one data set, this will be
    # necessary _after_ the previous step, not before. Data sets of one
    # long with negative values were causing infinite loops later on.
    ($min, $max) = ($max, $min) if ($min > $max);

my @n = ref($n_ref) ? @$n_ref : $n_ref;

if (@n <= 0)
    {
        @n = (3..6);
    }
    else
    {
        @n = map { ref($_) ? @$_ : /(\d+)/i ? $1 : (3..6) } @n;
    }

my $best_fit = 1e30;
    my $range = $max - $min;

# create array of interval sizes
    my $s = 1;
    while ($s < $range) { $s *= 10 }
    while ($s > $range) { $s /= 10 }
    my @step = map {$_ * $s} (0.2, 0.5, 1, 2, 5);

for my $n (@n) 
    {                               
        # Try all numbers of intervals
        next if ($n < 1);

for my $step (@step) 
        {
            next if ($n != 1) and ($step < $range/$n) || ($step <= 0); 
            # $step too small

my ($nice_min, $nice_max, $fit)
                    = _fit_interval($min, $max, $n, $step);

next if $best_fit <= $fit;

$best_min = $nice_min;
            $best_max = $nice_max;
            $best_fit = $fit;
            $best_num = $n;
        }
    }
    return ($best_min, $best_max, $best_num)
}

# CONTRIB Ben Tilly
#
# Calculate best endpoints and number of intervals for a pair of axes
# where it is trying to line up the scale of the two intervals.  It
# returns ($nice_min_1, $nice_max_1, $nice_min_2, $nice_max_2, $n),
# where $n is the number of intervals and
#
#    $nice_min_1 <= $min_1 < $max_1 <= $nice_max_1
#    $nice_min_2 <= $min_2 < $max_2 <= $nice_max_2
#
# and 0 will appear at the same point on both axes.
#
# Usage:
#       ($nmin_1,$nmax_1,$nmin_2,$nmax_2,$nint) = _best_dual_ends(247, 508, undef, -1, 5, undef, [2..5]);
# etc.  (The usage of the last arguments just parallels _best_ends.)
#
sub _best_dual_ends
{
    my ($min_1, $max_1) = _fit_vals_range(splice @_, 0, 3);
    my ($min_2, $max_2) = _fit_vals_range(splice @_, 0, 3);
    my @rem_args = @_;

# Fix the situation where both min_1 and max_1 are 0, which makes it
    # loop forever
    ($min_1, $max_1) = (0, 1) unless $min_1 or $max_1;

my $scale_1 = _max(abs($min_1), abs($max_1));
    my $scale_2 = _max(abs($min_2), abs($max_2));

$scale_1 = defined($scale_2) ? $scale_2 : 1 unless defined($scale_1);
    $scale_2 = $scale_1 unless defined($scale_2);

my $ratio = $scale_1 / ($scale_2 || 1);
    my $fact_1 = my $fact_2 = 1;

while ($ratio < sqrt(0.1))
    {
        $ratio *= 10;
        $fact_2 *= 10;
    }
    while ($ratio > sqrt(10))
    {
        $ratio /= 10;
        $fact_1 *= 10;
    }

my ($best_min_1, $best_max_1, $best_min_2, $best_max_2, $best_n, $best_fit)
            = ($min_1, $max_1, $min_2, $max_2, 1, 1e10);

# Now try all of the ratios of "simple numbers" in the right size-range
    foreach my $frac
    (
        [1,1], [1,2], [1,3], [2,1], [2,3], [2,5],
        [3,1], [3,2], [3,4], [3,5], [3,8], [3,10],
        [4,3], [4,5], [5,2], [5,3], [5,4], [5,6],
        [5,8], [6,5], [8,3], [8,5], [10,3]
    )
    {
        my $bfact_1 = $frac->[0] * $fact_1;
        my $bfact_2 = $frac->[1] * $fact_2;

my $min = _min( $min_1/$bfact_1, $min_2/$bfact_2 );
        my $max = _max( $max_1/$bfact_1, $max_2/$bfact_2 );

my ($bmin, $bmax, $n) = _best_ends($min, $max, @rem_args);
        my ($bmin_1, $bmax_1) = ($bfact_1*$bmin, $bfact_1*$bmax);
        my ($bmin_2, $bmax_2) = ($bfact_2*$bmin, $bfact_2*$bmax);

my $fit = _measure_interval_fit($bmin_1, $min_1, $max_1, $bmax_1)
                + _measure_interval_fit($bmin_2, $min_2, $max_2, $bmax_2);

next if $best_fit < $fit;

(
            $best_min_1, $best_max_1, $best_min_2, $best_max_2, 
            $best_n,     $best_fit
        ) = (
            $bmin_1,     $bmax_1,     $bmin_2,     $bmax_2,
            $n,          $fit
        );
    }

return ($best_min_1, $best_max_1, $best_min_2, $best_max_2, $best_n);
}

# Takes $min, $max, $step_count, $step_size.  Assumes $min <= $max and both
# $step_count and $step_size are positive.  Returns the fitted $min, $max,
# and a $fit statistic (where smaller is better).  Failure to fit the
# interval results in a poor fit statistic. :-)
sub _fit_interval
{
    my ($min, $max, $step_count, $step_size) = @_;

my $nice_min = $step_size * int($min/$step_size);
    $nice_min  -= $step_size if ($nice_min > $min);
    my $nice_max   = ($step_count == 1)
            ? $step_size * int($max/$step_size + 1)
            : $nice_min + $step_count * $step_size;

my $fit = _measure_interval_fit($nice_min, $min, $max, $nice_max);

# Prevent division by zero errors further up
    return ($min, $max, 0) if ($step_size == 0);
    return ($nice_min, $nice_max, $fit);
}

# Takes 2 values and a minimum range.  Returns a min and max which holds
# both values and is at least that minimum size
sub _fit_vals_range
{
    my ($min, $max, $min_range) = @_;

($min, $max) = ($max, $min) if $max < $min;

if (defined($min_range) and $min_range > $max - $min)
    {
        my $nice_min = $min_range * int($min/$min_range);
        $nice_min = $nice_min - $min_range if $min < $nice_min;
        my $nice_max = $max < $nice_min + $min_range
                ? $nice_min + $min_range
                : $max;
        ($min, $max) = ($nice_min, $nice_max);
    }
    return (0+$min, 0+$max);
}

# Takes $bmin, $min, $max, $bmax and returns a fit statistic for how well
# ($bmin, $bmax) encloses the interval ($min, $max).  Smaller is better,
# and failure to fit will be a very bad fit.  Assumes that $min <= $max
# and $bmin < $bmax.
sub _measure_interval_fit
{
    my ($bmin, $min, $max, $bmax) = @_;
    return 1000 if $bmin > $min or $bmax < $max;

my $range = $max - $min;
    my $brange = $bmax - $bmin;

return $brange < 10 * $range
            ? ($brange / $range)
            : 10;
 }

sub _get_bottom
{
    my $self = shift;
    my ($ds, $np) = @_;
    my $bottom = $self->{zeropoint};

if ($self->{cumulate} && $ds > 1)
    {
        my $left;
        my $pvalue = $self->{_data}->get_y_cumulative($ds - 1, $np);
        ($left, $bottom) = $self->val_to_pixel($np + 1, $pvalue, $ds);
        $bottom = $left if $self->{rotate_chart};
    }

return $bottom;
}

#
# Convert value coordinates to pixel coordinates on the canvas.
# TODO Clean up all the rotate_chart stuff
#
sub val_to_pixel    # ($x, $y, $dataset) or ($x, $y, -$axis) in real coords
{                   # return [x, y] in pixel coords
    my $self = shift;
    my ($x, $y, $i) = @_;

# XXX use_axis
    my $axis = 1;
    if ( $self->{two_axes} ) {
        $axis = $i < 0 ? -$i : $self->{use_axis}[$i - 1];
    }
    
    my $y_min = $self->{y_min}[$axis];
    my $y_max = $self->{y_max}[$axis];
    my $y_range = ($y_max - $y_min) || 1; 
    # XXX the above might be an appropriate place for a conditional warning

my $y_step = $self->{rotate_chart} ?
        abs(($self->{right} - $self->{left}) / $y_range) :
        abs(($self->{bottom} - $self->{top}) / $y_range);

my $ret_x;
    my $origin = $self->{rotate_chart} ? $self->{top} : $self->{left};

if (defined($self->{x_min_value}) && defined($self->{x_max_value}))
    {
        $ret_x = $origin + ($x - $self->{x_min}) * $self->{x_step};
    }
    else
    {
        $ret_x = ($self->{x_tick_number} ? $self->{x_offset} : $origin) 
            + $x * $self->{x_step};
    }
    my $ret_y = $self->{rotate_chart} ? 
        $self->{left} + ($y - $y_min) * $y_step :
        $self->{bottom} - ($y - $y_min) * $y_step;

return $self->{rotate_chart} ?
        (_round($ret_y), _round($ret_x)) :
        (_round($ret_x), _round($ret_y));
}

#
# Legend
#
sub setup_legend
{
    my $self = shift;

return unless defined $self->{legend};

my $maxlen = 0;
    my $num = 0;

# Save some variables
    $self->{r_margin_abs} = $self->{r_margin};
    $self->{b_margin_abs} = $self->{b_margin};

foreach my $legend (@{$self->{legend}})
    {
        if (defined($legend) and $legend ne "")
        {
            $self->{gdta_legend}->set_text($legend);
            my $len = $self->{gdta_legend}->get('width');
            $maxlen = ($maxlen > $len) ? $maxlen : $len;
            $num++;
        }
        last if $num >= $self->{_data}->num_sets;
    }

$self->{lg_num} = $num or return; 
    # not actually bug 20792 (unsure that this will ever get hit, but if it does..!)

# calculate the height and width of each element
    my $legend_height = _max($self->{lgfh}, $self->{legend_marker_height});

$self->{lg_el_width} = 
        $maxlen + $self->{legend_marker_width} + 3 * $self->{legend_spacing};
    $self->{lg_el_height} = $legend_height + 2 * $self->{legend_spacing};

my ($lg_pos, $lg_align) = split(//, $self->{legend_placement});

if ($lg_pos eq 'R')
    {
        # Always work in one column
        $self->{lg_cols} = 1;
        $self->{lg_rows} = $num;

# Just for completeness, might use this in later versions
        $self->{lg_x_size} = $self->{lg_cols} * $self->{lg_el_width};
        $self->{lg_y_size} = $self->{lg_rows} * $self->{lg_el_height};

# Adjust the right margin for the rest of the graph
        $self->{r_margin} += $self->{lg_x_size};

# Set the x starting point
        $self->{lg_xs} = $self->{width} - $self->{r_margin};

# Set the y starting point, depending on alignment
        if ($lg_align eq 'T')
        {
            $self->{lg_ys} = $self->{t_margin};
        }
        elsif ($lg_align eq 'B')
        {
            $self->{lg_ys} = $self->{height} - $self->{b_margin} - 
                $self->{lg_y_size};
        }
        else # default 'C'
        {
            my $height = $self->{height} - $self->{t_margin} - 
                $self->{b_margin};

$self->{lg_ys} = 
                int($self->{t_margin} + $height/2 - $self->{lg_y_size}/2) ;
        }
    }
    else # 'B' is the default
    {
        # What width can we use
        my $width = $self->{width} - $self->{l_margin} - $self->{r_margin};

(!defined($self->{lg_cols})) and 
            $self->{lg_cols} = int($width/$self->{lg_el_width}) || 1; # bug 20792
        
        $self->{lg_cols} = _min($self->{lg_cols}, $num);

$self->{lg_rows} = 
            int($num / $self->{lg_cols}) + (($num % $self->{lg_cols}) ? 1 : 0);

$self->{lg_x_size} = $self->{lg_cols} * $self->{lg_el_width};
        $self->{lg_y_size} = $self->{lg_rows} * $self->{lg_el_height};

# Adjust the bottom margin for the rest of the graph
        $self->{b_margin} += $self->{lg_y_size};

# Set the y starting point
        $self->{lg_ys} = $self->{height} - $self->{b_margin};

# Set the x starting point, depending on alignment
        if ($lg_align eq 'R')
        {
            $self->{lg_xs} = $self->{width} - $self->{r_margin} - 
                $self->{lg_x_size};
        }
        elsif ($lg_align eq 'L')
        {
            $self->{lg_xs} = $self->{l_margin};
        }
        else # default 'C'
        {
            $self->{lg_xs} =  
                int($self->{l_margin} + $width/2 - $self->{lg_x_size}/2);
        }
    }
}

sub draw_legend
{
    my $self = shift;

return unless defined $self->{legend};

my $xl = $self->{lg_xs} + $self->{legend_spacing};
    my $y  = $self->{lg_ys} + $self->{legend_spacing} - 1;
    
    my $i = 0;
    my $row = 1;
    my $x = $xl;    # start position of current element

foreach my $legend (@{$self->{legend}})
    {
        $i++;
        last if $i > $self->{_data}->num_sets;

my $xe = $x;    # position within an element

next unless defined($legend) && $legend ne "";

$self->draw_legend_marker($i, $xe, $y);

$xe += $self->{legend_marker_width} + $self->{legend_spacing};
        my $ys = int($y + $self->{lg_el_height}/2 - $self->{lgfh}/2);

$self->{gdta_legend}->set_text($legend);
        $self->{gdta_legend}->draw($xe, $ys);

$x += $self->{lg_el_width};

if (++$row > $self->{lg_cols})
        {
            $row = 1;
            $y += $self->{lg_el_height};
            $x = $xl;
        }
    }
}

#
# This will be virtual; every sub class should define their own
# if this one doesn't suffice
#
sub draw_legend_marker # data_set_number, x, y
{
    my $s = shift;
    my $n = shift;
    my $x = shift;
    my $y = shift;

my $g = $s->{graph};

my $ci = $s->set_clr($s->pick_data_clr($n));
    return unless defined $ci;

$y += int($s->{lg_el_height}/2 - $s->{legend_marker_height}/2);

$g->filledRectangle(
        $x, $y, 
        $x + $s->{legend_marker_width}, $y + $s->{legend_marker_height},
        $ci
    );

$g->rectangle(
        $x, $y, 
        $x + $s->{legend_marker_width}, $y + $s->{legend_marker_height},
        $s->{acci}
    );
}

"Just another true value";

.	Edit
..	Edit
Data.pm	Edit
Error.pm	Edit
FAQ.pod	Edit
area.pm	Edit
axestype.pm	Edit
bars.pm	Edit
colour.pm	Edit
hbars.pm	Edit
lines.pm	Edit
linespoints.pm	Edit
mixed.pm	Edit
pie.pm	Edit
points.pm	Edit
utils.pm	Edit