my-asciiart.perl

   1 #!/usr/bin/perl
   2
   3 if ($#ARGV < 1) {
   4         print STDERR "Usage: $ARGV0 <revision range>\n";
   5         exit(1);
   6 }
   7
   8 open INPUT, 'git rev-list --parents ' . join(' ', @ARGV) . '|';
   9
  10 %commits=();
  11 @list=();
  12
  13 sub add_parents ($$) {
  14         my $parents = $_[0];
  15         my $y = $_[1];
  16         foreach my $parent (split / /,$parents) {
  17                 if ($commits->{$parent} == undef) {
  18                         $commits->{$parent} = {
  19                                 'y' => $y++,
  20                                 'sha1' => $parent
  21                         };
  22                 } else {
  23                         if ($commits->{$parent}->{y} < $y) {
  24                                 $commits->{$parent}->{y} = $y++;
  25                         } else {
  26                                 $y = $commits->{$parent}->{y} + 1;
  27                         }
  28                 }
  29         }
  30 }
  31
  32 # expects output of `rev-list --parents --topo-order`
  33 $i = 0;
  34 while (<INPUT>) {
  35         if (/^([0-9a-f]{40}) ?(.*)$/) {
  36                 $sha1 = $1;
  37                 $parents = $2;
  38                 if ($commits->{$sha1} == undef) {
  39                         $commits->{$sha1} = {
  40                                 'y' => 0,
  41                                 'sha1' => $sha1,
  42                         };
  43                 } else {
  44                         $commits->{$sha1}->{index} = $#list;
  45                 }
  46                 $commits->{$sha1}->{parents} = $parents;
  47                 $list[$i] = $commits->{$sha1};
  48                 $commits->{$sha1}->{index} = $i++;
  49                 add_parents($parents, $commits->{$sha1}->{y});
  50         }
  51 }
  52 close INPUT;
  53
  54 if ($#list >= 26) {
  55         print STDERR "Cannot draw more than 26 revs.";
  56         exit(1);
  57 }
  58
  59 # make labels
  60 $height = 0;
  61 for ($i = 0; $i <= $#list; $i++) {
  62         $list[$i]->{x} = $#list - $i;
  63         $list[$i]->{label} = chr(0x41 + $list[$i]->{x});
  64         if ($height < $list[$i]->{y}) {
  65                 $height = $list[$i]->{y};
  66         }
  67 }
  68
  69 # make a canvas
  70 $width = $#list * 2 + 1;
  71 $height = $height * 2 + 1;
  72 @canvas = ();
  73 for ($i = 0; $i < $height; $i++) {
  74         $canvas[$i] = ' ' x $width . "\n";
  75 }
  76
  77 sub set_cell ($$$) {
  78         my $x = $_[0];
  79         my $y = $_[1];
  80         my $c = $_[2];
  81         $canvas[$y] = substr($canvas[$y], 0, $x) . $c .
  82                 substr($canvas[$y], $x + 1);
  83 }
  84
  85 sub get_cell ($$) {
  86         my $x = $_[0];
  87         my $y = $_[1];
  88         return substr($canvas[$y], $x, 1);
  89 }
  90
  91 sub msg($) {
  92         my $info = $_[0];
  93         return $info->{label} . ": " . $info->{x} . ", " . $info->{y};
  94 }
  95
  96 sub draw_line ($$) {
  97         my $commit1 = $_[0];
  98         my $commit2 = $_[1];
  99         my $x1 = $commit1->{x};
 100         my $y1 = $commit1->{y};
 101         my $x2 = $commit2->{x};
 102         my $y2 = $commit2->{y};
 103         if ($y1 == $y2) {
 104                 for (my $i = $x1 * 2 - 1; $i > $x2 * 2; $i--) {
 105                         set_cell($i, $y1 * 2, "-");
 106                 }
 107         } else {
 108                 my $is_straight = 0;
 109                 my $factor = ($y2 - $y1) / ($x1 - $x2);
 110                 my $i;
 111                 if ($x1 - $x2 == $y2 - $y1) {
 112                         $is_straight = 1;
 113                         for ($i = $x1 * 2 - 1; $i > $x2 * 2; $i -= 2) {
 114                                 my $y = $y1 * 2 + ($x1 * 2 - $i) * $factor;
 115                                 my $c = get_cell($i, int($y));
 116                                 if ($c ne ' ' && $c ne '-') {
 117                                         $is_straight = 0;
 118                                 }
 119                         }
 120                 }
 121                 if ($is_straight) {
 122                         for ($i = $x1 * 2 - 1; $i > $x2 * 2; $i--) {
 123                                 my $y = $y1 * 2 + ($x1 * 2 - $i) * $factor;
 124                                 my $c = (get_cell($i, int($y)) ne ' ') ?
 125                                         '+' : '/';
 126                                 set_cell($i, int($y), $c);
 127                         }
 128                 } else {
 129                         set_cell($x1 * 2 - 1, $y1 * 2 + 1, '\'');
 130                         for ($i = $x1 * 2 - 2; $i > $x2 * 2 + 1; $i--) {
 131                                 set_cell($i, $y1 * 2 + 1, '-');
 132                         }
 133                         set_cell($x2 * 2 + 1, $y1 * 2 + 1, ',');
 134                         for ($i = $y1 * 2 + 2; $i < $y2 * 2; $i++) {
 135                                 my $c = (get_cell($x2 * 2, $i) ne ' ') ?
 136                                         '+' : '|';
 137                                 set_cell($x2 * 2, $i, $c);
 138                         }
 139                 }
 140         }
 141 }
 142
 143 # draw it
 144 for ($i = 0; $i <= $#list; $i++) {
 145         $info = $list[$i];
 146         $x = $info->{x} * 2;
 147         $y = $info->{y} * 2;
 148         set_cell ($x, $y, $info->{label});
 149         foreach my $parent (split / /,$info->{parents}) {
 150                 if ($commits->{$parent}->{index} != undef) {
 151                         draw_line($info, $commits->{$parent});
 152                 }
 153         }
 154 }
 155
 156 print @canvas;
 157