File Coverage

lib/Graph/Easy/As_ascii.pm

Criterion	Covered	Total	%
statement	427	436	97.9
branch	248	288	86.1
condition	55	77	71.4
subroutine	28	28	100.0
pod	1	1	100.0
total	759	830	91.4

#############################################################################
# Render Nodes/Edges/Cells as ASCII/Unicode box drawing art
#
# (c) by Tels 2004-2007. Part of Graph::Easy
#############################################################################

package Graph::Easy::As_ascii;

$VERSION = '0.76';

use utf8;

#############################################################################
#############################################################################

package Graph::Easy::Edge::Cell;

use strict;
use warnings;

my $edge_styles = [
  {
  # style            hor, ver,   cross,	corner (SE, SW, NE, NW)
  'solid'	 => [ '--',  "|", '+', '+','+','+','+' ],	# simple line
  'double'	 => [ '==',  "H", "#", '#','#','#','#' ],	# double line
  'double-dash'	 => [ '= ',  '"', "#", '#','#','#','#' ],	# double dashed line
  'dotted'	 => [ '..',  ":", ':', '.','.','.','.' ],	# dotted
  'dashed'	 => [ '- ',  "'", '+', '+','+','+','+' ],	# dashed
  'dot-dash'	 => [ '.-',  "!", '+', '+','+','+','+' ],	# dot-dash
  'dot-dot-dash' => [ '..-', "!", '+', '+','+','+','+' ],	# dot-dot-dash
  'wave' 	 => [ '~~',  "}", '+', '*','*','*','*' ],	# wave
  'bold' 	 => [ '##',  "#", '#', '#','#','#','#' ],	# bold
  'bold-dash' 	 => [ '# ',  "#", '#', '#','#','#','#' ],	# bold-dash
  'wide' 	 => [ '##',  "#", '#', '#','#','#','#' ],	# wide
  'broad' 	 => [ '##',  "#", '#', '#','#','#','#' ],	# broad
  },
  {
  # style            hor, ver,   	    cross,     corner (SE, SW, NE, NW)
  'solid'	 => [ '─', '│', '┼',  '┌', '┐', '└', '┘' ],
  'double'	 => [ '═', '║', '╬',  '╔', '╗', '╚', '╝' ],
  'double-dash'	 => [ '═'.' ', '∥', '╬',  '╔', '╗', '╚', '╝' ], # double dashed
  'dotted'	 => [ '·', ':',     '┼',  '┌', '┐', '└', '┘' ], # dotted
  'dashed'	 => [ '╴', '╵', '┘',  '┌', '┐', '╵', '┘' ], # dashed
  'dot-dash'	 => [ '·'.'-',  "!",   '┼',  '┌', '┐', '└', '┘' ], # dot-dash
  'dot-dot-dash' => [ ('·' x 2).'-', "!",  '┼',  '┌', '┐', '└', '┘' ], # dot-dot-dash
  'wave' 	 => [ '∼', '≀',     '┼',  '┌', '┐', '└', '┘' ], # wave
  'bold' 	 => [ '━', '┃', '╋',  '┏', '┓', '┗', '┛' ], # bold
  'bold-dash' 	 => [ '━'.' ', '╻', '╋',  '┏', '┓', '┗', '┛' ], # bold-dash
  'broad' 	 => [ '▬', '▮', '█',  '█', '█', '█', '█' ], # wide
  'wide' 	 => [ '█', '█', '█',  '█', '█', '█', '█' ], # broad

# these two make it nec. to support multi-line styles for the vertical edge pieces
#  'broad-dash' 	 => [ '◼', '◼', '◼',  '◼', '◼', '◼', '◼' ], # broad-dash
#  'wide-dash' 	 => [ ('█'x 2) .'  ', '█', '█',  '█', '█', '█', '█' ], # wide-dash
  },
  ];

sub _edge_style
  {
  my ($self, $st) = @_;

  my $g = $self->{graph}->{_ascii_style} || 0;
  $st = $self->{style} unless defined $st;

  $edge_styles->[$g]->{ $st };
  }

  #    |       |        |        |        :        }       |
  # ===+=== ###+### ....!.... ~~~+~~~ ----+---  ...+... .-.+.-.-
  #    |       |        |        |        :        {       |

my $cross_styles = [
  # normal cross
  [
    {
    'boldsolid' 	=> '┿',
    'solidbold' 	=> '╂',
    'doublesolid' 	=> '╪',
    'soliddouble' 	=> '╫',
    'dashedsolid' 	=> '┤',
    'soliddashed' 	=> '┴',
    'doubledashed' 	=> '╧',
    'dasheddouble' 	=> '╢',
    },
    {
    'boldsolid'		=> '+',
    'dashedsolid'	=> '+',
    'dottedsolid'	=> '!',
    'dottedwave'	=> '+',
    'doublesolid'	=> '+',
    'dot-dashsolid'	=> '+',
    'dot-dot-dashsolid'	=> '+',
    'soliddotted'	=> '+',
    'solidwave'		=> '+',
    'soliddashed'	=> '+',
    'soliddouble'	=> 'H',
    'wavesolid'		=> '+',
    },
  ],
  undef,	# HOR, cannot happen
  undef,	# VER, cannot happen
  undef,
  undef,
  undef,
  undef,
  # S_E_W -+-
  #        |
  [
    {
    'solidsolid'		=> '┬',
    'boldbold'			=> '┳',
    'doubledouble'		=> '╦',
    'dasheddashed'		=> '╴',
    'dotteddotted'		=> '·',
    },
  ],
  # N_E_W  |
  #       -+-
  [
    {
    'solidsolid'		=> '┴',
    'boldbold'			=> '┻',
    'doubledouble'		=> '╩',
    'dotteddotted'		=> '·',
    },
  ],
  # E_N_S  |
  #        +-
  #        |
  [
    {
    'solidsolid'		=> '├',
    'boldbold'			=> '┣',
    'doubledouble'		=> '╠',
    'dotteddotted'		=> ':',
    },
  ],
  # W_N_S  |
  #       -+
  #        |
  [
    {
    'solidsolid'		=> '┤',
    'boldbold'			=> '┫',
    'doubledouble'		=> '╣',
    'dotteddotted'		=> ':',
    },
  ] ];

sub _arrow_style
  {
  my $self = shift;

  my $edge = $self->{edge};

  my $as = $edge->attribute('arrowstyle');
  $as = 'none' if $edge->{undirected};
  $as;
  }

sub _arrow_shape
  {
  my $self = shift;

  my $edge = $self->{edge};

  my $as = $edge->attribute('arrowshape');
  $as;
  }

sub _cross_style
  {
  my ($self, $st, $corner_type) = @_;

  my $g = $self->{graph}->{_ascii_style} || 0;

  # 0 => 1, 1 => 0
  $g = 1 - $g;

  # for ASCII, one style fist all (e.g a joint has still "+" as corner)
  $corner_type = 0 unless defined $corner_type;
  $corner_type = 0 if $g == 1;

  $cross_styles->[$corner_type]->[$g]->{ $st };
  }

sub _insert_label
  {
  my ($self, $fb, $xs, $ys, $ws, $hs, $align_ver) = @_;

  my $align = $self->{edge}->attribute('align');

  my ($lines,$aligns) = $self->_aligned_label($align);

  $ys = $self->{h} - scalar @$lines + $ys if $ys < 0;

  $ws ||= 0; $hs ||= 0;
  my $w = $self->{w} - $ws - $xs;
  my $h = $self->{h} - $hs - $ys;

  $self->_printfb_aligned ($fb, $xs, $ys, $w, $h, $lines, $aligns, $align_ver);
  }

sub _draw_hor
  {
  # draw a HOR edge piece
  my ($self, $fb) = @_;

  my $style = $self->_edge_style();

  my $w = $self->{w};
  # '-' => '-----', '.-' => '.-.-.-'
  # "(2 + ... )" to get space for the offset
  my $len = length($style->[0]);
  my $line = $style->[0] x (2 + $w / $len);

  # '.-.-.-' => '-.-.-' if $x % $ofs == 1 (e.g. on odd positions)
  my $ofs = $self->{rx} % $len;
  my $type = ($self->{type} & (~EDGE_MISC_MASK));
  substr($line,0,$ofs) = '' if $ofs != 0
    && ($type != EDGE_SHORT_E && $type != EDGE_SHORT_W);

  $line = substr($line, 0, $w) if length($line) > $w;

  # handle start/end point

  my $flags = $self->{type} & EDGE_FLAG_MASK;

  my $as = $self->_arrow_style();
  my $ashape; $ashape = $self->_arrow_shape() if $as ne 'none';

  my $x = 0;				# offset for the edge line
  my $xs = 1;				# offset for the edge label
  my $xr = 0;				# right offset for label
  if (($flags & EDGE_START_W) != 0)
    {
    $x++; chop($line);			# ' ---'
    $xs++;
    }
  if (($flags & EDGE_START_E) != 0)
    {
    chop($line);			# '--- '
    }

  if (($flags & EDGE_END_E) != 0)
    {
    # '--> '
    chop($line);
    substr($line,-1,1) = $self->_arrow($as, ARROW_RIGHT, $ashape) if $as ne 'none';
    $xr++;
    }
  if (($flags & EDGE_END_W) != 0)
    {
    # ' <--'
    substr($line,0,1) = ' ' if $as eq 'none';
    substr($line,0,2) = ' ' . $self->_arrow($as, ARROW_LEFT, $ashape) if $as ne 'none';
    $xs++;
    }

  $self->_printfb_line ($fb, $x, $self->{h} - 2, $line);

  $self->_insert_label($fb, $xs, 0, $xs+$xr, 2, 'bottom' )
   if ($self->{type} & EDGE_LABEL_CELL);

  }

sub _draw_ver
  {
  # draw a VER edge piece
  my ($self, $fb) = @_;

  my $style = $self->_edge_style();

  my $h = $self->{h};
  # '|' => '|||||', '{}' => '{}{}{}'
  my $line = $style->[1] x (1 + $h / length($style->[1]));
  $line = substr($line, 0, $h) if length($line) > $h;

  my $flags = $self->{type} & EDGE_FLAG_MASK;
  # XXX TODO: handle here start points
  # we get away with not handling them because in VER edges
  # starting points are currently invisible.

  my $as = $self->_arrow_style();
  if ($as ne 'none')
    {
    my $ashape = $self->_arrow_shape();
    substr($line,0,1) = $self->_arrow($as,ARROW_UP, $ashape)
      if (($flags & EDGE_END_N) != 0);
    substr($line,-1,1) = $self->_arrow($as,ARROW_DOWN, $ashape)
      if (($flags & EDGE_END_S) != 0);
    }
  $self->_printfb_ver ($fb, 2, 0, $line);

  $self->_insert_label($fb, 4, 1, 4, 2, 'middle')
    if ($self->{type} & EDGE_LABEL_CELL);

  }

sub _draw_cross
  {
  # draw a CROSS sections, or a joint (which is a 3/4 cross)
  my ($self, $fb) = @_;

  # vertical piece
  my $style = $self->_edge_style( $self->{style_ver} );

  my $invisible = 0;
  my $line;
  my $flags = $self->{type} & EDGE_FLAG_MASK;
  my $type = $self->{type} & EDGE_TYPE_MASK;
  my $as = $self->_arrow_style();
  my $y = $self->{h} - 2;

  print STDERR "# drawing cross at $self->{x},$self->{y} with flags $flags\n" if $self->{debug};

  if ($self->{style_ver} ne 'invisible')
    {
    my $h = $self->{h};
    # '|' => '|||||', '{}' => '{}{}{}'
    $line = $style->[1] x (2 + $h / length($style->[1]));

    $line = substr($line, 0, $h) if length($line) > $h;

    if ($as ne 'none')
      {
      my $ashape = $self->_arrow_shape();
      substr($line,0,1) = $self->_arrow($as,ARROW_UP, $ashape)
        if (($flags & EDGE_END_N) != 0);
      substr($line,-1,1) = $self->_arrow($as,ARROW_DOWN, $ashape)
        if (($flags & EDGE_END_S) != 0);
      }

    # create joints
    substr($line,0,$y) = ' ' x $y if $type == EDGE_S_E_W;
    substr($line,$y,2) = '  ' if $type == EDGE_N_E_W;

    $self->_printfb_ver ($fb, 2, 0, $line);
    }
  else { $invisible++; }

  # horizontal piece
  $style = $self->_edge_style();

  my $ashape; $ashape = $self->_arrow_style() if $as ne 'none';

  if ($self->{style} ne 'invisible')
    {
    my $w = $self->{w};
    # '-' => '-----', '.-' => '.-.-.-'
    my $len = length($style->[0]);
    $line = $style->[0] x (2 + $w / $len);

    # '.-.-.-' => '-.-.-' if $x % $ofs == 1 (e.g. on odd positions)
    my $ofs = $self->{rx} % $len;
    substr($line,0,$ofs) = '' if $ofs != 0;

    $line = substr($line, 0, $w) if length($line) > $w;

    my $x = 0;
    if (($flags & EDGE_START_W) != 0)
      {
      $x++; chop($line);		# ' ---'
      }
    if (($flags & EDGE_START_E) != 0)
      {
      chop($line);			# '--- '
      }
    if (($flags & EDGE_END_E) != 0)
      {
      # '--> '
      chop($line);
      substr($line,-1,1) = $self->_arrow($as, ARROW_RIGHT, $ashape)
       if $as ne 'none';
      }
    if (($flags & EDGE_END_W) != 0)
      {
      # ' <--'
      substr($line,0,1) = ' ' if $as eq 'none';
      substr($line,0,2) = ' ' . $self->_arrow($as, ARROW_LEFT, $ashape)
       if $as ne 'none';
      }

    substr($line,0,2) = '  ' if $type == EDGE_E_N_S;
    substr($line,2,$self->{w}-2) = ' ' x ($self->{w}-2) if $type == EDGE_W_N_S;

    $self->_printfb_line ($fb, $x, $y, $line);
    }
  else { $invisible++; }

  if (!$invisible)
    {
    # draw the crossing character only if both lines are visible
    my $cross = $style->[2];
    my $s = $self->{style} . $self->{style_ver};
    $cross = ($self->_cross_style($s,$type) || $cross); # if $self->{style_ver} ne $self->{style};

    $self->_printfb ($fb, 2, $y, $cross);
    }

  # done
  }

sub _draw_corner
  {
  # draw a corner (N_E, S_E etc)
  my ($self, $fb) = @_;

  my $type = $self->{type} & EDGE_TYPE_MASK;
  my $flags = $self->{type} & EDGE_FLAG_MASK;

  ############
  #   ........
  # 0 :      :
  # 1 :      :    label would appear here
  # 2 :  +---:    (w-3) = 3 chars wide
  # 3 :  |   :    always 1 char high
  #   .......:
  #    012345

  # draw the vertical piece

  # get the style
  my $style = $self->_edge_style();

  my $h = 1; my $y = $self->{h} -1;
  if ($type == EDGE_N_E || $type == EDGE_N_W)
    {
    $h = $self->{h} - 2; $y = 0;
    }
  # '|' => '|||||', '{}' => '{}{}{}'
  my $line = $style->[1] x (1 + $h / length($style->[1]));
  $line = substr($line, 0, $h) if length($line) > $h;

  my $as = $self->_arrow_style();
  my $ashape;
  if ($as ne 'none')
    {
    $ashape = $self->_arrow_shape();
    substr($line,0,1) = $self->_arrow($as, ARROW_UP, $ashape)
      if (($flags & EDGE_END_N) != 0);
    substr($line,-1,1) = $self->_arrow($as, ARROW_DOWN, $ashape)
      if (($flags & EDGE_END_S) != 0);
    }
  $self->_printfb_ver ($fb, 2, $y, $line);

  # horizontal piece
  my $w = $self->{w} - 3; $y = $self->{h} - 2; my $x = 3;
  if ($type == EDGE_N_W || $type == EDGE_S_W)
    {
    $w = 2; $x = 0;
    }

  # '-' => '-----', '.-' => '.-.-.-'
  my $len = length($style->[0]);
  $line = $style->[0] x (2 + $w / $len);

  # '.-.-.-' => '-.-.-' if $x % $ofs == 1 (e.g. on odd positions)
  my $ofs = ($x + $self->{rx}) % $len;
  substr($line,0,$ofs) = '' if $ofs != 0;

  $line = substr($line, 0, $w) if length($line) > $w;

  substr($line,-1,1) = ' ' if ($flags & EDGE_START_E) != 0;
  substr($line,0,1) = ' '  if ($flags & EDGE_START_W) != 0;

  if (($flags & EDGE_END_E) != 0)
    {
    substr($line,-1,1) = ' ' if $as eq 'none';
    substr($line,-2,2) = $self->_arrow($as, ARROW_RIGHT, $ashape) . ' ' if $as ne 'none';
    }
  if (($flags & EDGE_END_W) != 0)
    {
    substr($line,0,1) = ' ' if $as eq 'none';
    substr($line,0,2) = ' ' . $self->_arrow($as, ARROW_LEFT, $ashape) if $as ne 'none';
    }

  $self->_printfb_line ($fb, $x, $y, $line);

  my $idx = 3; 		# corner (SE, SW, NE, NW)
  $idx = 4 if $type == EDGE_S_W;
  $idx = 5 if $type == EDGE_N_E;
  $idx = 6 if $type == EDGE_N_W;

  # insert the corner character
  $self->_printfb ($fb, 2, $y, $style->[$idx]);
  }

sub _draw_loop_hor
  {
  my ($self, $fb) = @_;

  my $type = $self->{type} & EDGE_TYPE_MASK;
  my $flags = $self->{type} & EDGE_FLAG_MASK;

  ############
  #   ..........
  # 0 :        :
  # 1 :        :    label would appear here
  # 2 :  +--+  :    (w-6) = 2 chars wide
  # 3 :  |  v  :    1 char high
  #   .........:
  #    01234567

  ############
  #   ..........
  # 0 :  |  ^  :    ver is h-2 chars high
  # 1 :  |  |  :    label would appear here
  # 2 :  +--+  :    (w-6) = 2 chars wide
  # 3 :        :
  #   .........:
  #    01234567

  # draw the vertical pieces

  # get the style
  my $style = $self->_edge_style();

  my $h = 1; my $y = $self->{h} - 1;
  if ($type == EDGE_S_W_N)
    {
    $h = $self->{h} - 2; $y = 0;
    }
  # '|' => '|||||', '{}' => '{}{}{}'
  my $line = $style->[1] x (1 + $h / length($style->[1]));
  $line = substr($line, 0, $h) if length($line) > $h;

  my $as = $self->_arrow_style();
  my $ashape; $ashape = $self->_arrow_shape() if $as ne 'none';

  if ($self->{edge}->{bidirectional} && $as ne 'none')
    {
    substr($line,0,1)  = $self->_arrow($as, ARROW_UP, $ashape) if (($flags & EDGE_END_N) != 0);
    substr($line,-1,1) = $self->_arrow($as, ARROW_DOWN, $ashape) if (($flags & EDGE_END_S) != 0);
    }
  $self->_printfb_ver ($fb, $self->{w}-3, $y, $line);

  if ($as ne 'none')
    {
    substr($line,0,1)  = $self->_arrow($as, ARROW_UP, $ashape) if (($flags & EDGE_END_N) != 0);
    substr($line,-1,1) = $self->_arrow($as, ARROW_DOWN, $ashape) if (($flags & EDGE_END_S) != 0);
    }
  $self->_printfb_ver ($fb, 2, $y, $line);

  # horizontal piece
  my $w = $self->{w} - 6; $y = $self->{h} - 2; my $x = 3;

  # '-' => '-----', '.-' => '.-.-.-'
  my $len = length($style->[0]);
  $line = $style->[0] x (2 + $w / $len);

  # '.-.-.-' => '-.-.-' if $x % $ofs == 1 (e.g. on odd positions)
  my $ofs = ($x + $self->{rx}) % $len;
  substr($line,0,$ofs) = '' if $ofs != 0;

  $line = substr($line, 0, $w) if length($line) > $w;

  $self->_printfb_line ($fb, $x, $y, $line);

  my $corner_idx = 3; $corner_idx = 5 if $type == EDGE_S_W_N;

  # insert the corner characters
  $self->_printfb ($fb, 2, $y, $style->[$corner_idx]);
  $self->_printfb ($fb, $self->{w}-3, $y, $style->[$corner_idx+1]);

  my $align = 'bottom'; $align = 'top' if $type == EDGE_S_W_N;
  $self->_insert_label($fb, 4, 0, 4, 2, $align)
  if ($self->{type} & EDGE_LABEL_CELL);

  # done
  }

sub _draw_loop_ver
  {
  my ($self, $fb) = @_;

  my $type = $self->{type} & EDGE_TYPE_MASK;
  my $flags = $self->{type} & EDGE_FLAG_MASK;

  ############
  #   ........
  # 0 :      :  label would appear here
  # 1 :  +-- :
  # 2 :  |   :
  # 3 :  +-> :
  #   .......:
  #    012345

  #   ........
  # 0 :      :  label would appear here
  # 1 : --+  :
  # 2 :   |  :
  # 3 : <-+  :
  #   .......:
  #    012345

  ###########################################################################
  # draw the vertical piece

  # get the style
  my $style = $self->_edge_style();

  my $h = 1; my $y = $self->{h} - 3;
  # '|' => '|||||', '{}' => '{}{}{}'
  my $line = $style->[1] x (1 + $h / length($style->[1]));
  $line = substr($line, 0, $h) if length($line) > $h;

  my $x = 2; $x = $self->{w}-3 if ($type == EDGE_E_S_W);
  $self->_printfb_ver ($fb, $x, $y, $line);

  ###########################################################################
  # horizontal pieces

  my $w = $self->{w} - 3; $y = $self->{h} - 4;
  $x = 2; $x = 1 if ($type == EDGE_E_S_W);

  # '-' => '-----', '.-' => '.-.-.-'
  my $len = length($style->[0]);
  $line = $style->[0] x (2 + $w / $len);

  # '.-.-.-' => '-.-.-' if $x % $ofs == 1 (e.g. on odd positions)
  my $ofs = ($x + $self->{rx}) % $len;
  substr($line,0,$ofs) = '' if $ofs != 0;

  $line = substr($line, 0, $w) if length($line) > $w;

  my $as = $self->_arrow_style();
  my $ashape; $ashape = $self->_arrow_shape() if $as ne 'none';

  if ($self->{edge}->{bidirectional} && $as ne 'none')
    {
    substr($line,0,1)  = $self->_arrow($as, ARROW_LEFT, $ashape) if (($flags & EDGE_END_W) != 0);
    substr($line,-1,1) = $self->_arrow($as, ARROW_RIGHT, $ashape) if (($flags & EDGE_END_E) != 0);
    }

  $self->_printfb_line ($fb, $x, $y, $line);

  if ($as ne 'none')
    {
    substr($line,0,1)  = $self->_arrow($as, ARROW_LEFT, $ashape) if (($flags & EDGE_END_W) != 0);
    substr($line,-1,1) = $self->_arrow($as, ARROW_RIGHT, $ashape) if (($flags & EDGE_END_E) != 0);
    }

  $self->_printfb_line ($fb, $x, $self->{h} - 2, $line);

  $x = 2; $x = $self->{w}-3 if ($type == EDGE_E_S_W);

  my $corner_idx = 3; $corner_idx = 4 if $type == EDGE_E_S_W;

  # insert the corner characters
  $self->_printfb ($fb, $x, $y, $style->[$corner_idx]);
  $self->_printfb ($fb, $x, $self->{h}-2, $style->[$corner_idx+2]);

  $x = 4; $x = 3 if ($type == EDGE_E_S_W);
  $self->_insert_label($fb, $x, 0, $x, 4, 'bottom')
    if ($self->{type} & EDGE_LABEL_CELL);

  # done
  }

# which method to call for which edge type
my $draw_dispatch =
  {
  EDGE_HOR() => '_draw_hor',
  EDGE_VER() => '_draw_ver',

  EDGE_S_E() => '_draw_corner',
  EDGE_S_W() => '_draw_corner',
  EDGE_N_E() => '_draw_corner',
  EDGE_N_W() => '_draw_corner',

  EDGE_CROSS() => '_draw_cross',
  EDGE_W_N_S() => '_draw_cross',
  EDGE_E_N_S() => '_draw_cross',
  EDGE_N_E_W() => '_draw_cross',
  EDGE_S_E_W() => '_draw_cross',

  EDGE_N_W_S() => '_draw_loop_hor',
  EDGE_S_W_N() => '_draw_loop_hor',

  EDGE_E_S_W() => '_draw_loop_ver',
  EDGE_W_S_E() => '_draw_loop_ver',
  };

sub _draw_label
  {
  # This routine is cunningly named _draw_label, because it actually
  # draws the edge line(s). The label text will be drawn by the individual
  # routines called below.
  my ($self, $fb, $x, $y) = @_;

  my $type = $self->{type} & EDGE_TYPE_MASK;

  # for cross sections, we maybe need to draw one of the parts:
  return if $self->attribute('style') eq 'invisible' && $type ne EDGE_CROSS;

  my $m = $draw_dispatch->{$type};

  $self->_croak("Unknown edge type $type") unless defined $m;

  # store the coordinates of our upper-left corner (for seamless rendering)
  $self->{rx} = $x || 0; $self->{ry} = $y || 0;
  $self->$m($fb);
  delete $self->{rx}; delete $self->{ry};	# no longer needed
  }

#############################################################################
#############################################################################

package Graph::Easy::Node;

use strict;

sub _framebuffer
  {
  # generate an actual framebuffer consisting of spaces
  my ($self, $w, $h) = @_;

  print STDERR "# trying to generate framebuffer of undefined width for $self->{name}\n",
               join (": ", caller(),"\n") if !defined $w;

  my @fb;

  my $line = ' ' x $w;
  for my $y (1..$h)
    {
    push @fb, $line;
    }
  \@fb;
  }

sub _printfb_aligned
  {
  my ($self,$fb, $x1,$y1, $w,$h, $lines, $aligns, $align_ver) = @_;

  $align_ver = 'middle' unless $align_ver;

  # $align_ver eq 'middle':
  my $y = $y1 + ($h / 2) - (scalar @$lines / 2);
  if ($align_ver eq 'top')
    {
    $y = $y1;
    $y1 = 0;
    }
  if ($align_ver eq 'bottom')
    {
    $y = $h - scalar @$lines; $y1 = 0;
    }

  my $xc = ($w / 2);

  my $i = 0;
  while ($i < @$lines)
    {
    # get the line and her alignment
    my ($l,$al) = ($lines->[$i],$aligns->[$i]);

    my $x = 0;			# left is default

    $x = $xc - length($l) / 2 if $al eq 'c';
    $x = $w - length($l) if $al eq 'r';

    # now print the line (inlined print_fb_line for speed)
    substr ($fb->[int($y+$i+$y1)], int($x+$x1), length($l)) = $l;

    $i++;
    }
  }

sub _printfb_line
  {
  # Print one textline into a framebuffer
  # Caller MUST ensure proper size of FB, for speed reasons,
  # we do not check whether text fits!
  my ($self, $fb, $x, $y, $l) = @_;

  # [0] = '0123456789...'

  substr ($fb->[$y], $x, length($l)) = $l;
  }

sub _printfb
  {
  # Print (potential a multiline) text into a framebuffer
  # Caller MUST ensure proper size of FB, for speed reasons,
  # we do not check whether the text fits!
  my ($self, $fb, $x, $y, @lines) = @_;

  # [0] = '0123456789...'
  # [1] = '0123456789...' etc

  for my $l (@lines)
    {
#    # XXX DEBUG:
#    if ( $x + length($l) > length($fb->[$y]))
#      {
#      require Carp;
#      Carp::confess("substr outside framebuffer");
#      }

    substr ($fb->[$y], $x, length($l)) = $l; $y++;
    }
  }

sub _printfb_ver
  {
  # Print a string vertical into a framebuffer.
  # Caller MUST ensure proper size of FB, for speed reasons,
  # we do not check whether text fits!
  my ($self, $fb, $x, $y, $line) = @_;

  # this more than twice as fast as:
  #  "@pieces = split//,$line; _printfb(...)"

  my $y1 = $y + length($line);
  substr ($fb->[$y1], $x, 1) = chop($line) while ($y1-- > $y);
  }

 # for ASCII and box drawing:

 # the array contains for each style:
 # upper left edge
 # upper right edge
 # lower right edge
 # lower left edge
 # hor style (top edge)
 # hor style (bottom side)
 # ver style (right side) (multiple characters possible)
 # ver style (left side) (multiple characters possible)
 # T crossing (see drawing below)
 # T to right
 # T to left
 # T to top
 # T shape (to bottom)

 #
 # +-----4-----4------+
 # |     |     |      |
 # |     |     |      |
 # |     |     |      |
 # 1-----0-----3------2		1 = T to right, 2 = T to left, 3 T to top
 # |     |			0 = cross, 4 = T shape
 # |     |
 # |     |
 # +-----+

my $border_styles =
  [
  {
  solid =>		[ '+', '+', '+', '+', '-',   '-',   [ '|'      ], [ '|'     ], '+', '+', '+', '+', '+' ],
  dotted =>		[ '.', '.', ':', ':', '.',   '.',   [ ':'      ], [ ':'     ], '.', '.', '.', '.', '.' ],
  dashed =>		[ '+', '+', '+', '+', '- ',  '- ',  [ "'"      ], [ "'"     ], '+', '+', '+', '+', '+' ],
  'dot-dash' =>		[ '+', '+', '+', '+', '.-',  '.-',  [ '!'      ], [ '!'     ], '+', '+', '+', '+', '+' ],
  'dot-dot-dash' =>	[ '+', '+', '+', '+', '..-', '..-', [ '|', ':' ], [ '|',':' ], '+', '+', '+', '+', '+' ],
  bold =>		[ '#', '#', '#', '#', '#',   '#',   [ '#'      ], [ '#'     ], '#', '#', '#', '#', '#' ],
  'bold-dash' =>	[ '#', '#', '#', '#', '# ',  '# ',  ['#',' '   ], [ '#',' ' ], '#', '#', '#', '#', '#' ],
  double =>		[ '#', '#', '#', '#', '=',   '=',   [ 'H'      ], [ 'H'     ], '#', '#', '#', '#', '#' ],
  'double-dash' =>	[ '#', '#', '#', '#', '= ',  '= ',  [ '"'      ], [ '"'     ], '#', '#', '#', '#', '#' ],
  wave =>		[ '+', '+', '+', '+', '~',   '~',   [ '{', '}' ], [ '{','}' ], '+', '+', '+', '+', '+' ],
  broad =>		[ '#', '#', '#', '#', '#',   '#',   [ '#'      ], [ '#'     ], '#', '#', '#', '#', '#' ],
  wide =>		[ '#', '#', '#', '#', '#',   '#',   [ '#'      ], [ '#'     ], '#', '#', '#', '#', '#' ],
  none =>		[ ' ', ' ', ' ', ' ', ' ',   ' ',   [ ' '      ], [ ' '     ], ' ', ' ', ' ', ' ', ' ' ],
  },
  {
  solid =>		[ '┌', '┐', '┘', '└', '─', '─',     [ '│' ], [ '│' ], '┼', '├', '┤', '┴', '┬' ],
  double =>		[ '╔', '╗', '╝', '╚', '═', '═',     [ '║' ], [ '║' ], '┼', '├', '┤', '┴', '┬' ],
  dotted =>		[ '┌', '┐', '┘', '└', '⋯', '⋯', [ '⋮' ], [ '⋮' ], '┼', '├', '┤', '┴', '┬' ],
  dashed =>		[ '┌', '┐', '┘', '└', '−', '−', [ '╎' ], [ '╎' ], '┼', '├', '┤', '┴', '┬' ],
  'dot-dash' =>		[ '┌', '┐', '┘', '└', '·'.'-', '·'.'-', ['!'], ['!'], '┼', '├', '┤', '┴', '┬' ],
  'dot-dot-dash' =>	[ '┌', '┐', '┘', '└', ('·' x 2) .'-', ('·' x 2) .'-', [ '│', ':' ], [ '│', ':' ], '┼', '├', '┤', '┴', '┬' ],
  bold =>		[ '┏', '┓', '┛', '┗', '━', '━', [ '┃' ], [ '┃' ], '┼', '├', '┤', '┴', '┬' ],
  'bold-dash' =>	[ '┏', '┓', '┛', '┗', '━'.' ', '━'.' ', [ '╻' ], [ '╻' ], '┼', '├', '┤', '┴', '┬' ],
  'double-dash' =>	[ '╔', '╗', '╝', '╚', '═'.' ', '═'.' ', [ '∥' ], [ '∥' ], '┼', '├', '┤', '┴', '┬' ],
  wave =>		[ '┌', '┐', '┘', '└', '∼',  '∼', [ '≀' ], [ '≀' ], '┼', '├', '┤', '┴', '┬' ],
  broad =>		[ '▛', '▜', '▟', '▙', '▀', '▄', [ '▌' ], [ '▐' ], '▄', '├', '┤', '┴', '┬' ],
  wide =>		[ '█', '█', '█', '█', '█', '█', [ '█' ], [ '█' ], '█', '█', '█', '█', '█' ],
  none =>		[ ' ', ' ', ' ', ' ', ' ', ' ',  [ ' ' ], [ ' ' ], ' ', ' ', ' ', ' ', ' ', ],
  },
  ];

 # for boxart and rounded corners on node-borders:
 # upper left edge
 # upper right edge
 # lower right edge
 # lower left edge

my $rounded_edges = [ '╭', '╮', '╯', '╰', ];

 # for ASCII/boxart drawing slopes/slants
 #             lower-left to upper right (repeated twice)
 #                   lower-right to upper left (repeated twice)
my $slants = [
  # ascii
  {
  solid	 	 => [ '/'  , '\\'   ],
  dotted	 => [ '.' , '.'     ],
  dashed	 => [ '/ ', '\\ '   ],
  'dot-dash'	 => [ './', '.\\'   ],
  'dot-dot-dash' => [ '../', '..\\' ],
  bold	 	 => [ '#' , '#'     ],
  'bold-dash' 	 => [ '# ' , '# '   ],
  'double' 	 => [ '/' , '\\'    ],
  'double-dash'	 => [ '/ ' , '\\ '  ],
  wave	 	 => [ '/ ' , '\\ '  ],
  broad	 	 => [ '#' , '#'     ],
  wide	 	 => [ '#' , '#'     ],
  },
  # boxart
  {
  solid	 	 => [ '╱'  , '╲'   ],
  dotted	 => [ '⋰' , '⋱'    ],
  dashed	 => [ '╱ ', '╲ '   ],
  'dot-dash'	 => [ '.╱', '.╲'   ],
  'dot-dot-dash' => [ '⋰╱', '⋱╲' ],
  bold	 	 => [ '#' , '#'    ],
  'bold-dash' 	 => [ '# ' , '# '  ],
  'double' 	 => [ '╱' , '╲'    ],
  'double-dash'	 => [ '╱ ' , '╲ '  ],
  wave	 	 => [ '╱ ' , '╲ '  ],
  broad	 	 => [ '#' , '#'    ],
  wide	 	 => [ '#' , '#'    ],
  },
  ];

 # ASCII and box art: the different point shapes and styles
my $point_shapes =
  [ {
    filled =>
      {
      'star'		=> '*',
      'square'		=> '#',
      'dot'		=> '.',
      'circle'		=> 'o',  # unfortunately, there is no filled o in ASCII
      'cross'		=> '+',
      'diamond'		=> '<>',
      'x'		=> 'X',
      },
    closed =>
      {
      'star'		=> '*',
      'square'		=> '#',
      'dot'		=> '.',
      'circle'		=> 'o',
      'cross'		=> '+',
      'diamond'		=> '<>',
      'x'		=> 'X',
      },
    },
    {
    filled =>
      {
      'star'		=> '★',
      'square'		=> '■',
      'dot'		=> '·',
      'circle'		=> '●',
      'cross'		=> '+',
      'diamond'		=> '◆',
      'x'		=> '╳',
      },
    closed =>
      {
      'star'		=> '☆',
      'square'		=> '□',
      'dot'		=> '·',
      'circle'		=> '○',
      'cross'		=> '+',
      'diamond'		=> '◇',
      'x'		=> '╳',
      },
    }
  ];

sub _point_style
  {
  my ($self, $shape, $style) = @_;

  return '' if $shape eq 'invisible';

  if ($style =~ /^(star|square|dot|circle|cross|diamond)\z/)
    {
    # support the old "pointstyle: diamond" notion:
    $shape = $style; $style = 'filled';
    }

  $style = 'filled' unless defined $style;
  my $g = $self->{graph}->{_ascii_style} || 0;
  $point_shapes->[$g]->{$style}->{$shape};
  }

sub _border_style
  {
  my ($self, $style, $type) = @_;

  # make a copy so that we can modify it
  my $g = $self->{graph}->{_ascii_style} || 0;
  my $s = [ @{ $border_styles->[ $g ]->{$style} } ];

  die ("Unknown $type border style '$style'") if @$s == 0;

  my $shape = 'rect';
  $shape = $self->attribute('shape') unless $self->isa_cell();
  return $s unless $shape eq 'rounded';

  # if shape: rounded, overlay the rounded edge pieces
  splice (@$s, 0, 4, @$rounded_edges)
    if $style =~ /^(solid|dotted|dashed|dot-dash|dot-dot-dash)\z/;

  # '####' => ' ### '
  splice (@$s, 0, 4, (' ', ' ', ' ', ' '))
    if $g == 0 || $style =~ /^(bold|wide|broad|double|double-dash|bold-dash)\z/;

  $s;
  }

#############################################################################
# different arrow styles and shapes in ASCII and boxart

my $arrow_form =
  {
  normal => 0,
  sleek => 1,			# slightly squashed
  };

my $arrow_shapes =
  {
  triangle => 0,
  diamond => 1,
  box => 2,
  dot => 3,
  inv => 4,			# an inverted triangle
  line => 5,
  cross => 6,
  x => 7,
  };

# todo: ≪ ≫

my $arrow_styles =
  [
    [
    # triangle
      {
      open   => [ '>', '<', '^', 'v' ],
      closed => [ '>', '<', '^', 'v' ],
      filled => [ '>', '<', '^', 'v' ],
      },
      {
      open   => [ '>', '<', '∧', '∨' ],
      closed => [ '▷', '◁', '△', '▽' ],
      filled => [ '▶', '◀', '▲', '▼' ],
      }
    ], [
    # diamond
      {
      open   => [ '>', '<', '^', 'v' ],
      closed => [ '>', '<', '^', 'v' ],
      filled => [ '>', '<', '^', 'v' ],
      },
      {
      open   => [ '>', '<', '∧', '∨' ],
      closed => [ '◇', '◇', '◇', '◇' ],
      filled => [ '◆', '◆', '◆', '◆' ],
      }
    ], [
    # box
      {
      open   => [ ']', '[', '°', 'u' ],
      closed => [ 'D', 'D', 'D', 'D' ],
      filled => [ '#', '#', '#', '#' ],
      },
      {
      open   => [ '⊐', '⊐', '⊓', '⊔' ],
      closed => [ '◻', '◻', '◻', '◻' ],
      filled => [ '◼', '◼', '◼', '◼' ],
      }
    ], [
    # dot
      {
      open   => [ ')', '(', '^', 'u' ],
      closed => [ 'o', 'o', 'o', 'o' ],
      filled => [ '*', '*', '*', '*' ],
      },
      {
      open   => [ ')', '(', '◠', '◡' ],
      closed => [ '○', '○', '○', '○' ],
      filled => [ '●', '●', '●', '●' ],
      }
    ], [
    # inv
      {
      open   => [ '<', '>', 'v', '^' ],
      closed => [ '<', '>', 'v', '^' ],
      filled => [ '<', '>', 'v', '^' ],
      },
      {
      open   => [ '<', '>', '∨', '∧' ],
      closed => [ '◁', '▷', '▽', '△' ],
      filled => [ '◀', '▶', '▼', '▲' ],
      }
    ], [
    # line
      {
      open   => [ '|', '|', '_', '-' ],
      closed => [ '|', '|', '_', '-' ],
      filled => [ '|', '|', '_', '-' ],
      },
      {
      open   => [ '⎥', '⎢', '_', '¯' ],
      closed => [ '⎥', '⎢', '_', '¯' ],
      filled => [ '⎥', '⎢', '_', '¯' ],
      }
    ], [
    # cross
      {
      open   => [ '+', '+', '+', '+' ],
      closed => [ '+', '+', '+', '+' ],
      filled => [ '+', '+', '+', '+' ],
      },
      {
      open   => [ '┼', '┼', '┼', '┼' ],
      closed => [ '┼', '┼', '┼', '┼' ],
      filled => [ '┼', '┼', '┼', '┼' ],
      }
    ], [
    # x
      {
      open   => [ 'x', 'x', 'x', 'x' ],
      closed => [ 'x', 'x', 'x', 'x' ],
      filled => [ 'x', 'x', 'x', 'x' ],
      },
      {
      open   => [ 'x', 'x', 'x', 'x' ],
      closed => [ 'x', 'x', 'x', 'x' ],
      filled => [ '⧓', '⧓', 'x', 'x' ],
      }
    ]
  ];

sub _arrow
  {
  # return an arror, depending on style and direction
  my ($self, $style, $dir, $shape) = @_;

  $shape = '' unless defined $shape;
  $shape = $arrow_shapes->{$shape} || 0;

  my $g = $self->{graph}->{_ascii_style} || 0;
  $arrow_styles->[$shape]->[$g]->{$style}->[$dir];
  }

# To convert an HTML arrow to Unicode:
my $arrow_dir = {
  '>' => 0,
  '<' => 1,
  '^' => 2,
  'v' => 3,
  };

sub _unicode_arrow
  {
  # return an arror in unicode, depending on style and direction
  my ($self, $shape, $style, $arrow_text) = @_;

  $shape = '' unless defined $shape;
  $shape = $arrow_shapes->{$shape} || 0;

  my $dir = $arrow_dir->{$arrow_text} || 0;

  $arrow_styles->[$shape]->[1]->{$style}->[$dir];
  }

#############################################################################

#
# +---4---4---4---+
# |   |   |   |   |
# |   |   |   |   |
# |   |   |   |   |
# 1---0---3---0---2	1 = T to right, 2 = T to left, 3 T to top
# |   |       |   |	0 = cross, 4 = T shape
# |   |       |   |
# |   |       |   |
# +---+       +---+

sub _draw_border
  {
  # draws a border into the framebuffer
  my ($self, $fb, $do_right, $do_bottom, $do_left, $do_top, $x, $y) = @_;

  return if $do_right.$do_left.$do_bottom.$do_top eq 'nonenonenonenone';

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

  my $w = $self->{w};
  if ($do_top ne 'none')
    {
    my $style = $self->_border_style($do_top, 'top');

    # top-left corner piece is only there if we have a left border
    my $tl = $style->[0]; $tl = '' if $do_left eq 'none';

    # generate the top border
    my $top = $style->[4] x (($self->{w}) / length($style->[4]) + 1);

    my $len = length($style->[4]);

    # for seamless rendering
    if (defined $x)
      {
      my $ofs = $x % $len;
      substr($top,0,$ofs) = '' if $ofs != 0;
      }

    # insert left upper corner (if it is there)
    substr($top,0,1) = $tl if $tl ne '';

    $top = substr($top,0,$w) if length($top) > $w;

    # top-right corner piece is only there if we have a right border
    substr($top,-1,1) = $style->[1] if $do_right ne 'none';

    # if the border must be collapsed, modify top-right edge piece:
    if ($self->{border_collapse_right})
      {
      # place "4" (see drawing above)
      substr($top,-1,1) = $style->[10];
      }

    # insert top row into FB
    $self->_printfb( $fb, 0,0, $top);
    }

  if ($do_bottom ne 'none')
    {
    my $style = $self->_border_style($do_bottom, 'bottom');

    # bottom-left corner piece is only there if we have a left border
    my $bl = $style->[3]; $bl = '' if $do_left eq 'none';

    # the bottom row '+--------+' etc
    my $bottom = $style->[5] x (($self->{w}) / length($style->[5]) + 1);

    my $len = length($style->[5]);

    # for seamless rendering
    if (defined $x)
      {
      my $ofs = $x % $len;
      substr($bottom,0,$ofs) = '' if $ofs != 0;
      }

    # insert left bottom corner (if it is there)
    substr($bottom,0,1) = $bl if $bl ne '';

    $bottom = substr($bottom,0,$w) if length($bottom) > $w;

    # bottom-right corner piece is only there if we have a right border
    substr($bottom,-1,1) = $style->[2] if $do_right ne 'none';

    # if the border must be collapsed, modify bottom-right edge piece:
    if ($self->{border_collapse_right} || $self->{border_collapse_bottom})
      {
      if ($self->{rightbelow_count} > 0)
        {
        # place a cross or T piece (see drawing above)
        my $piece = 8;	# cross
        # inverted T
        $piece = 11 if $self->{rightbelow_count} < 2 && !$self->{have_below};
        $piece = 10 if $self->{rightbelow_count} < 2 && !$self->{have_right};
        substr($bottom,-1,1) = $style->[$piece];
        }
      }

    # insert bottom row into FB
    $self->_printfb( $fb, 0,$self->{h}-1, $bottom);
    }

  return if $do_right.$do_left eq 'nonenone';	# both none => done

  my $style = $self->_border_style($do_left, 'left');
  my $left = $style->[6];
  my $lc = scalar @{ $style->[6] } - 1;		# count of characters

  $style = $self->_border_style($do_right, 'right');
  my $right = $style->[7];
  my $rc = scalar @{ $style->[7] } - 1;		# count of characters

  my (@left, @right);
  my $l = 0; my $r = 0;				# start with first character
  my $s = 1; $s = 0 if $do_top eq 'none';

  my $h = $self->{h} - 2;
  $h ++ if defined $x && $do_bottom eq 'none';	# for seamless rendering
  for ($s..$h)
    {
    push @left, $left->[$l]; $l ++; $l = 0 if $l > $lc;
    push @right, $right->[$r]; $r ++; $r = 0 if $r > $rc;
    }
  # insert left/right columns into FB
  $self->_printfb( $fb, 0, $s, @left) unless $do_left eq 'none';
  $self->_printfb( $fb, $w-1, $s, @right) unless $do_right eq 'none';

  $self;
  }

sub _draw_label
  {
  # Draw the node label into the framebuffer
  my ($self, $fb, $x, $y, $shape) = @_;

  if ($shape eq 'point')
    {
    # point-shaped nodes do not show their label in ASCII
    my $style = $self->attribute('pointstyle');
    my $shape = $self->attribute('pointshape');
    my $l = $self->_point_style($shape,$style);

    $self->_printfb_line ($fb, 2, $self->{h} - 2, $l) if $l;
    return;
    }

  #        +----
  #        | Label
  # 2,1: ----^

  my $w = $self->{w} - 4; my $xs = 2;
  my $h = $self->{h} - 2; my $ys = 0.5;
  my $border = $self->attribute('borderstyle');
  if ($border eq 'none')
    {
    $w += 2; $h += 2;
    $xs = 1; $ys = 0;
    }

  my $align = $self->attribute('align');
  $self->_printfb_aligned ($fb, $xs, $ys, $w, $h, $self->_aligned_label($align));
  }

sub as_ascii
  {
  # renders a node or edge like:
  # +--------+    ..........    ""
  # | A node | or : A node : or " --> "
  # +--------+    ..........    ""
  my ($self, $x,$y) = @_;

  my $shape = 'rect';
  $shape = $self->attribute('shape') unless $self->isa_cell();

  if ($shape eq 'edge')
    {
    my $edge = Graph::Easy::Edge->new();
    my $cell = Graph::Easy::Edge::Cell->new( edge => $edge, x => $x, y => $y );
    $cell->{w} = $self->{w};
    $cell->{h} = $self->{h};
    $cell->{att}->{label} = $self->label();
    $cell->{type} =
     Graph::Easy::Edge::Cell->EDGE_HOR +
     Graph::Easy::Edge::Cell->EDGE_LABEL_CELL;
    return $cell->as_ascii();
    }

  # invisible nodes, or very small ones
  return '' if $shape eq 'invisible' || $self->{w} == 0 || $self->{h} == 0;

  my $fb = $self->_framebuffer($self->{w}, $self->{h});

  # point-shaped nodes do not have a border
  if ($shape ne 'point')
    {
    #########################################################################
    # draw our border into the framebuffer

    my $cache = $self->{cache};
    my $b_top = $cache->{top_border} || 'none';
    my $b_left = $cache->{left_border} || 'none';
    my $b_right = $cache->{right_border} || 'none';
    my $b_bottom = $cache->{bottom_border} || 'none';

    $self->_draw_border($fb, $b_right, $b_bottom, $b_left, $b_top);
    }

  ###########################################################################
  # "draw" the label into the framebuffer (e.g. the node/edge and the text)

  $self->_draw_label($fb, $x, $y, $shape);

  join ("\n", @$fb);
  }

1;
__END__