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#==========================================================================
#              Copyright (c) 1995-1998 Martien Verbruggen
#--------------------------------------------------------------------------
#
#   Name:
#       GD::Graph::pie.pm
#
# $Id: pie.pm,v 1.21 2007/04/26 03:16:09 ben Exp $
#
#==========================================================================

package GD::Graph::pie;

($GD::Graph::pie::VERSION) = '$Revision: 1.21 $' =~ /\s([\d.]+)/;

use strict;

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

use GD;
use GD::Graph;
use GD::Graph::utils qw(:all);
use GD::Graph::colour qw(:colours :lists);
use GD::Text::Align;
use Carp;

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

my $ANGLE_OFFSET = 90;

my %Defaults = (
 
    # Set the height of the pie.
    # Because of the dependency of this on runtime information, this
    # is being set in GD::Graph::pie::initialise
 
    #   pie_height => _round(0.1*${'width'}),
    pie_height  => undef,
 
    # Do you want a 3D pie?
    '3d'        => 1,
 
    # The angle at which to start the first data set
    # 0 is at the front/bottom
    start_angle => 0,

# Angle below which a label on a pie slice is suppressed.
    suppress_angle => 0,    # CONTRIB idea ryan <xomina@bitstream.net>

# and some public attributes without defaults
    label       => undef,

# This misnamed attribute is used for pie marker colours
    axislabelclr => 'black',
);

# PRIVATE
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( pie_height => _round(0.1 * $self->{height}) );
    $self->set_value_font(gdTinyFont);
    $self->set_label_font(gdSmallFont);
}

# PUBLIC methods, documented in pod
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_coords()           or return;
    $self->draw_text()              or return;
    $self->draw_pie()               or return;
    $self->draw_data()              or return;

return $self->{graph};
}

sub set_label_font # (fontname)
{
    my $self = shift;
    $self->_set_font('gdta_label', @_) or return;
    $self->{gdta_label}->set_align('bottom', 'center');
}

sub set_value_font # (fontname)
{
    my $self = shift;
    $self->_set_font('gdta_value', @_) or return;
    $self->{gdta_value}->set_align('center', 'center');
}

# Inherit defaults() from GD::Graph

# inherit checkdata from GD::Graph

# Setup the coordinate system and colours, calculate the
# relative axis coordinates in respect to the canvas size.

sub setup_coords()
{
    my $self = shift;

# Make sure we're not reserving space we don't need.
    $self->{'3d'} = 0           if     $self->{pie_height} <= 0;
    $self->set(pie_height => 0) unless $self->{'3d'};

my $tfh = $self->{title} ? $self->{gdta_title}->get('height') : 0;
    my $lfh = $self->{label} ? $self->{gdta_label}->get('height') : 0;

# Calculate the bounding box for the pie, and
    # some width, height, and centre parameters (don't forget fenceposts!)
    $self->{bottom} = 
        $self->{height} - $self->{pie_height} - $self->{b_margin} -
        ( $lfh ? $lfh + $self->{text_space} : 0 ) - 1;
    $self->{top} = 
        $self->{t_margin} + ( $tfh ? $tfh + $self->{text_space} : 0 );

return $self->_set_error('Vertical size too small') 
        if $self->{bottom} - $self->{top} <= 0;

$self->{left} = $self->{l_margin};
    $self->{right} = $self->{width} - $self->{r_margin} - 1;

# ensure that the center is a single pixel, not a half-pixel position
    $self->{right}--  if ($self->{right} - $self->{left}) % 2;
    $self->{bottom}-- if ($self->{bottom} - $self->{top}) % 2;

return $self->_set_error('Horizontal size too small')
        if $self->{right} - $self->{left} <= 0;

$self->{w} = $self->{right}  - $self->{left} + 1;
    $self->{h} = $self->{bottom} - $self->{top} + 1;

$self->{xc} = ($self->{right}  + $self->{left})/2; 
    $self->{yc} = ($self->{bottom} + $self->{top})/2;

return $self;
}

# inherit open_graph from GD::Graph

# Setup the parameters for the text elements
sub setup_text
{
    my $self = shift;

if ( $self->{title} ) 
    {
        #print "'$s->{title}' at ($s->{xc},$s->{t_margin})\n";
        $self->{gdta_title}->set(colour => $self->{tci});
        $self->{gdta_title}->set_text($self->{title});
    }

if ( $self->{label} ) 
    {
        $self->{gdta_label}->set(colour => $self->{lci});
        $self->{gdta_label}->set_text($self->{label});
    }

$self->{gdta_value}->set(colour => $self->{alci});

return $self;
}

# Put the text on the canvas.
sub draw_text
{
    my $self = shift;

$self->{gdta_title}->draw($self->{xc}, $self->{t_margin}) 
        if $self->{title}; 
    $self->{gdta_label}->draw($self->{xc}, $self->{height} - $self->{b_margin})
        if $self->{label};
    
    return $self;
}

# draw the pie, without the data slices
sub draw_pie
{
    my $self = shift;

my $left = $self->{xc} - $self->{w}/2;

$self->{graph}->arc(
        $self->{xc}, $self->{yc}, 
        $self->{w}, $self->{h},
        0, 360, $self->{acci}
    );

$self->{graph}->arc(
        $self->{xc}, $self->{yc} + $self->{pie_height}, 
        $self->{w}, $self->{h},
        0, 180, $self->{acci}
    ) if ( $self->{'3d'} );

$self->{graph}->line(
        $left, $self->{yc},
        $left, $self->{yc} + $self->{pie_height}, 
        $self->{acci}
    );

$self->{graph}->line(
        $left + $self->{w}, $self->{yc},
        $left + $self->{w}, $self->{yc} + $self->{pie_height}, 
        $self->{acci}
    );

return $self;
}

# Draw the data slices

sub draw_data
{
    my $self = shift;

my $total = 0;
    my @values = $self->{_data}->y_values(1);   # for now, only one pie..
    for (@values)
    {   
        $total += $_ 
    }

return $self->_set_error("Pie data total is <= 0") 
        unless $total > 0;

my $ac = $self->{acci};         # Accent colour
    my $pb = $self->{start_angle};

for (my $i = 0; $i < @values; $i++)
    {
        next unless $values[$i];
        # Set the data colour
        my $dc = $self->set_clr_uniq($self->pick_data_clr($i + 1));

# Set the angles of the pie slice
        # Angle 0 faces down, positive angles are clockwise 
        # from there.
        #         ---
        #        /   \
        #        |    |
        #        \ | /
        #         ---
        #          0
        # $pa/$pb include the start_angle (so if start_angle
        # is 90, there will be no pa/pb < 90.
        my $pa = $pb;
        $pb += my $slice_angle = 360 * $values[$i]/$total;

# Calculate the end points of the lines at the boundaries of
        # the pie slice
        my ($xe, $ye) = cartesian(
                $self->{w}/2, $pa, 
                $self->{xc}, $self->{yc}, $self->{h}/$self->{w}
            );

$self->{graph}->line($self->{xc}, $self->{yc}, $xe, $ye, $ac);

# Draw the lines on the front of the pie
        $self->{graph}->line($xe, $ye, $xe, $ye + $self->{pie_height}, $ac)
            if in_front($pa) && $self->{'3d'};

# Make an estimate of a point in the middle of the pie slice
        # And fill it
        ($xe, $ye) = cartesian(
                3 * $self->{w}/8, ($pa+$pb)/2,
                $self->{xc}, $self->{yc}, $self->{h}/$self->{w}
            );

$self->{graph}->fillToBorder($xe, $ye, $ac, $dc);

# If it's 3d, colour the front ones as well
        #
        # if one slice is very large (>180 deg) then we will need to
        # fill it twice.  sbonds.
        #
        # Independently noted and fixed by Jeremy Wadsack, in a slightly
        # different way.
        if ($self->{'3d'}) 
        {
            foreach my $fill ($self->_get_pie_front_coords($pa, $pb)) 
            {
                my ($fx,$fy) = @$fill;
                my $new_y = $fy + $self->{pie_height}/2;
                # Edge case (literally): if lines have converged, back up 
                # looking for a gap to fill
                while ( $new_y > $fy ) {
                    if ($self->{graph}->getPixel($fx,$new_y) != $ac) {
                        $self->{graph}->fillToBorder($fx, $new_y, $ac, $dc);
                        last;
                    }
                } continue { $new_y-- }
            }
        }
    }

# CONTRIB Jeremy Wadsack
    #
    # Large text, sticking out over the pie edge, could cause 3D pies to
    # fill improperly: Drawing the text for a given slice before the
    # next slice was drawn and filled could make the slice boundary
    # disappear, causing the fill colour to flow out.  With this
    # implementation, all the text is on top of the pie.

$pb = $self->{start_angle};
    for (my $i = 0; $i < @values; $i++)
    {
        next unless $values[$i];

my $pa = $pb;
        $pb += my $slice_angle = 360 * $values[$i]/$total;

next if $slice_angle <= $self->{suppress_angle};

my ($xe, $ye) = 
            cartesian(
                3 * $self->{w}/8, ($pa+$pb)/2,
                $self->{xc}, $self->{yc}, $self->{h}/$self->{w}
            );

$self->put_slice_label($xe, $ye, $self->{_data}->get_x($i));
    }

return $self;

} #GD::Graph::pie::draw_data

sub _get_pie_front_coords # (angle 1, angle 2)
{
    my $self = shift;
    my $pa = level_angle(shift);
    my $pb = level_angle(shift);
    my @fills = ();

if (in_front($pa))
    {
        if (in_front($pb))
        {
            # both in front
            # don't do anything
            # Ah, but if this wraps all the way around the back
            # then both pieces of the front need to be filled.
            # sbonds.
            if ($pa >= $pb ) 
            {
                # This takes care of the left bit on the front
                # Since we know exactly where we are, and in which
                # direction this works, we can just get the coordinates
                # for $pa.
                my ($x, $y) = cartesian(
                    $self->{w}/2, $pa,
                    $self->{xc}, $self->{yc}, $self->{h}/$self->{w}
                );

# and move one pixel to the left, but only if we don't
                # fall out of the pie!.
                push @fills, [$x - 1, $y]
                    if $x - 1 > $self->{xc} - $self->{w}/2;

# Reset $pa to the right edge of the front arc, to do
                # the right bit on the front.
                $pa = level_angle(-$ANGLE_OFFSET);
            }
        }
        else
        {
            # start in front, end in back
            $pb = $ANGLE_OFFSET;
        }
    }
    else
    {
        if (in_front($pb))
        {
            # start in back, end in front
            $pa = $ANGLE_OFFSET - 180;
        }
        elsif ( # both in back, but wrapping around the front
                # CONTRIB kedlubnowski, Dan Rosendorf 
            $pa >= $pb && ($pa < 0 || $pb > 0)
            or $pa < 0 && $pb > 0
        ) 
        {   
            $pa=$ANGLE_OFFSET - 180;
            $pb=$ANGLE_OFFSET;
        }
        else
        {
            return;
        }
    }

my ($x, $y) = cartesian(
        $self->{w}/2, ($pa + $pb)/2,
        $self->{xc}, $self->{yc}, $self->{h}/$self->{w}
    );

push @fills, [$x, $y];

return @fills;
}

# return true if this angle is on the front of the pie
# XXX UGLY! We need to leave a slight room for error because of rounding
# problems
sub in_front
{
    my $a = level_angle(shift);
    return 
        $a > ($ANGLE_OFFSET - 180 + 0.00000001) && 
        $a < $ANGLE_OFFSET - 0.000000001;
}

# XXX Ugh! I need to fix this. See the GD::Text module for better ways
# of doing this.
# return a value for angle between -180 and 180
sub level_angle # (angle)
{
    my $a = shift;
    return level_angle($a-360) if ( $a > 180 );
    return level_angle($a+360) if ( $a <= -180 );
    return $a;
}

# put the slice label on the pie
sub put_slice_label
{
    my $self = shift;
    my ($x, $y, $label) = @_;

return unless defined $label;

$self->{gdta_value}->set_text($label);
    $self->{gdta_value}->draw($x, $y);
}

# return x, y coordinates from input
# radius, angle, center x and y and a scaling factor (height/width)
#
# $ANGLE_OFFSET is used to define where 0 is meant to be
sub cartesian
{
    my ($r, $phi, $xi, $yi, $cr) = @_;

return map _round($_), (
        $xi + $r * cos(PI * ($phi + $ANGLE_OFFSET)/180), 
        $yi + $cr * $r * sin(PI * ($phi + $ANGLE_OFFSET)/180)
    )
}

"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