Draw nodes with at least l edges.

README.md

@@ -3,7 +3,7 @@
 [vimwiki](https://github.com/vimwiki/vimwiki) directory and builds a
 graph between the encountered files and their internal references. The
 code supports vimwiki-style links `[[link]]`, `[[link|description]]`
-and markdown-style links `(description)[link]`. The graph is 
+and markdown-style links `(description)[link]`. The graph is
 converted to the DOT language
 using [`dot`](https://github.com/emicklei/dot). The results can then be
 visualised with [graphviz](https://www.graphviz.org/about/), e.g. using
@@ -20,6 +20,11 @@ providing new insights.
 
 `-cluster`: cluster subdirectories as subgraphs
 
+`-l`: only nodes with at least `l` edges are inserted. The inserted nodes are
+inserted with all their edges. Thus, nodes with less than `l` edges can appear
+when they are connected to other nodes that do satisfy the requirement.
+For `-l 0`, all nodes are inserted.
+
 ## Examples
 To illustrate `/example/` contains some `.wiki` files and also a
 diary, `/example/diary/*.wiki`. Running `vimwikigraph` produces the

main.go

@@ -26,6 +26,7 @@ func main() {
 
 	cluster := flag.Bool("cluster", false, "cluster nodes in sub directories")
 	diary := flag.Bool("diary", false, "collapse all diary entries under a single `diary.wiki` node")
+	level := flag.Int("l", 1, "draw only edges from nodes with at least level number of edges")
 	flag.Parse()
 
 	// remap any path that contains `diary` into `diary.wiki`
@@ -49,7 +50,7 @@ func main() {
 	}
 
 	// convert to a dot-graph for visualisation
-	g := wiki.Dot(dot.Directed)
+	g := wiki.Dot(*level, dot.Directed)
 	g.Attr("rankdir", "LR")
 	g.Write(os.Stdout)
 }

vimwikigraph.go

@@ -210,10 +210,14 @@ func (wiki *Wiki) Add(path string) error {
 
 // Dot converts wiki.graph into dot.Graph.
 //
+// Only nodes, and their connections, are drawn if their sum of edges
+// is greater than the provided level. For `level = 0` all nodes
+// are inserted.
+//
 // If wiki.cluster == true any nodes that correspond to a subdirectory are
 // inserted in the corresponding subgraph of that subdirectory. By default, the
 // visualisation will highlight these subgraphs.
-func (wiki *Wiki) Dot(opts ...dot.GraphOption) *dot.Graph {
+func (wiki *Wiki) Dot(level int, opts ...dot.GraphOption) *dot.Graph {
 	graph := dot.NewGraph()
 	for _, opt := range opts {
 		opt.Apply(graph)
@@ -223,8 +227,8 @@ func (wiki *Wiki) Dot(opts ...dot.GraphOption) *dot.Graph {
 
 	for k, val := range wiki.graph {
 
-		// only draw nodes with connection
-		if len(val) == 0 {
+		// skip nodes with less edges
+		if len(val) < level {
 			continue
 		}
 

vimwikigraph_test.go

@@ -1,7 +1,11 @@
 package main
 
 import (
+	"fmt"
+	"os"
 	"testing"
+
+	"github.com/emicklei/dot"
 )
 
 type match struct {
@@ -193,3 +197,38 @@ func TestMatchParseWikiLinks(t *testing.T) {
 		}
 	}
 }
+
+func TestNodeConnectionLevel(t *testing.T) {
+	os.Chdir(".")
+	dir, _ := os.Executable()
+	t.Log(dir)
+	wiki := newWiki("example", make(map[string]string), false)
+
+	// build 0 < i < 10 entries with each i connections, where the current
+	// nodes are not considered as connections
+	wiki.graph = make(map[string][]string)
+	for i := 0; i < 10; i++ {
+		k := fmt.Sprintf("%d", i)
+		wiki.graph[k] = make([]string, 0, 0)
+		for j := 0; j < i; j++ {
+			wiki.graph[k] = append(wiki.graph[k], fmt.Sprintf("%d00", j))
+		}
+	}
+
+	// level zero: 9 entries + 10 connections: 19 nodes in total
+	// each increment of the level should draw one node less
+	for l := 0; l < 10; l++ {
+		g := wiki.Dot(l, dot.Directed)
+		nconn := len(g.FindNodes())
+		exp := 19 - l
+		if nconn != exp {
+			t.Errorf("For level %v: exp: %v, got %v", l, exp, nconn)
+		}
+	}
+
+	// higher than maximum connectivity should result in zero nodes
+	nconn := len(wiki.Dot(10, dot.Directed).FindNodes())
+	if nconn > 0 {
+		t.Errorf("Expected 0 connections, got %v", nconn)
+	}
+}