add underlay files for listdirectives

As was noted, 'listdirectives' didn't include the underlay files that make
it really worthwhile.  I've just gone through all the plugin
documentation, modified it to remove installation information and renamed
the files to match the directives rather than the plugins.  This can now
serve as useful underlay.

I've only gone through plugins in the 'plugins' dir.  I did not go through
the 'contrib' dir.

1 files changed, 28 insertions, 0 deletions

diff --git a/underlays/basewiki/directive/linkmap.mdwn b/underlays/basewiki/directive/linkmap.mdwn
new file mode 100644
index 000000000..8466e0465
--- /dev/null
+++ b/underlays/basewiki/directive/linkmap.mdwn
@@ -0,0 +1,28 @@
+The `linkmap` directive is supplied by the [[!iki plugins/linkmap]] plugin.
+
+This directive uses [graphviz](http://www.graphviz.org/) to generate a graph showing the links between a
+set of pages in the wiki. Example usage:
+
+	\[[!linkmap pages="* and !blog/* and !*/Discussion"]]
+
+Only links between mapped pages will be shown; links pointing to or from
+unmapped pages will be omitted. If the pages to include are not specified,
+the links between all pages (and other files) in the wiki are mapped. For
+best results, only a small set of pages should be mapped, since otherwise
+the map can become very large, unweildy, and complicated. Also, the map is
+rebuilt whenever one of the mapped pages is changed, which can make the
+wiki a bit slow.
+
+Here are descriptions of all the supported parameters to the `linkmap`
+directive:
+
+* `pages` - A [[ikiwiki/PageSpec]] of the pages to map.
+* `height`, `width` - Limit the size of the map to a given height and width,
+  in inches. Both must be specified for the limiting to take effect, otherwise
+  the map's size is not limited.
+
+[[!if test="enabled(linkmap)" then="""
+Here is an example link map, of the index page and all pages it links to:
+
+[[!linkmap pages="index or (backlink(index) and !*.png)"]]
+"""]]