make relationship mapper segments adapt to node+edge size of graph

diff --git a/stemmaweb/lib/stemmaweb/Controller/Relation.pm b/stemmaweb/lib/stemmaweb/Controller/Relation.pm
index c44b544..0082624 100644 (file)
--- a/stemmaweb/lib/stemmaweb/Controller/Relation.pm
+++ b/stemmaweb/lib/stemmaweb/Controller/Relation.pm
@@ -70,18 +70,30 @@ sub text :Chained('/') :PathPart('relation') :CaptureArgs(1) {
        my( $self, $c, $textid ) = @_;
        # If the tradition has more than 500 ranks or so, split it up.
        my $tradition = $c->model('Directory')->tradition( $textid );
+       # See how big the tradition is. Edges are more important than nodes
+       # when it comes to rendering difficulty.
+       my $numnodes = scalar $tradition->collation->readings;
+       my $numedges = scalar $tradition->collation->paths;
        my $length = $tradition->collation->end->rank;
-       if( $length > 700 ) {
+       # We should display no more than roughly 500 nodes, or roughly 700
+       # edges, at a time.
+       my $segments = $numnodes / 500;
+       if( $numedges / 700 > $segments ) {
+               $segments = $numedges / 700;
+       }
+       my $segsize = sprintf( "%.0f", $length / $segments );
+       my $margin = sprintf( "%.0f", $segsize / 10 );
+       if( $segments > 1 ) {
                # Segment the tradition in order not to overload the browser.
-               # Split it up into units of 500 ranks, but have each segment show
-               # 550 ranks so that overlap works.
                my @divs;
                my $r = 0;
-               while( $r + 50 < $length ) {
+               while( $r + $margin < $length ) {
                        push( @divs, $r );
-                       $r += 500;
+                       $r += $segsize;
                }
                $c->stash->{'textsegments'} = [];
+               $c->stash->{'segsize'} = $segsize;
+               $c->stash->{'margin'} = $margin;
                foreach my $i ( 0..$#divs ) {
                        my $seg = { 'start' => $divs[$i] };
                        $seg->{'display'} = "Segment " . ($i+1);
@@ -100,16 +112,17 @@ sub main :Chained('text') :PathPart('') :Args(0) {
        my $collation = $tradition->collation;
        my $svgopts;
        if( $startseg ) {
-               # Only render the subgraph from startseg to +550 or end,
+               # Only render the subgraph from startseg to endseg or to END,
                # whichever is less.
+               my $endseg = $startseg + $c->stash->{'segsize'} + $c->stash->{'margin'};
                $svgopts = { 'from' => $startseg };
-               $svgopts->{'to'} = $startseg + 550
-                       if $startseg + 550 < $collation->end->rank;
+               $svgopts->{'to'} = $endseg if $endseg < $collation->end->rank;
        } elsif( exists $c->stash->{'textsegments'} ) {
                # This is the unqualified load of a long tradition. We implicitly start 
                # at zero, but go only as far as 550.
+               my $endseg = $c->stash->{'segsize'} + $c->stash->{'margin'};
                $startseg = 0;
-               $svgopts = { 'to' => 550 };
+               $svgopts = { 'to' => $endseg };
        }
        my $svg_str = $collation->as_svg( $svgopts );
        $svg_str =~ s/\n//gs;