commit 72dec5ebc99e38738123a6a99a263dfe2920299d
Author: FliegendeWurst <2012gdwu+github@posteo.de>
Date:   Sun May 29 15:05:23 2022 +0200

    Initial commit

diff --git a/README.md b/README.md
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+# Hypergraph drawing using Graphviz and Asymptote
+
+## Usage
+
+Requires Python 3, [pydot](https://pypi.org/project/pydot/) (tested with 1.4.2), [Asymptote](https://asymptote.sourceforge.io/) (tested with 2.67) and LaTeX (tested with TeX Live 2021).
+
+To render a hypergraph specified in `graph.dot`, execute the following:
+```bash
+cat graph.dot | dot -Tdot | python3 ./dot_hypergraph_to_asymptote.py /dev/stdin > graph.asy
+asy -f png graph.asy
+```
+You may adjust the font size, width/height of the output and more by editing the values at the beginning of the script.
+
+## Example
+
+| Original graph | Asymptote rendering |
+| -------------- | ------------------- |
+| ![dot rendering](./graph_dot.png) | ![asymptote rendering](./graph.png) |
+
+`graph.dot`:
+```
+digraph {
+	edge [dir="back"];
+	"Node 1" -> "Node 2" [label="Edge 1"]
+	"Node 1" -> "Node 3" [label="Edge 1"]
+	"Node 3" -> "Node 4" [label="Edge 2"]
+	"Node 3" -> "Node 5" [label="Edge 2"]
+	"Node 5" -> "Node 6" [label="Edge 3"]
+	"Node 4" -> "Node 6" [label="Edge 3"]
+	"Node 2" -> "Node 7" [label="Edge 4"]
+	"Node 6" -> "Node 7" [label="Edge 4"]
+	"Node 2" -> "Node 8" [label="Edge 5"]
+	"Node 7" -> "Node 8" [label="Edge 5"]
+}
+```
+
+## Credits
+
+The generated code is based on https://tex.stackexchange.com/a/108099/185782 by g.kov.
+
+## License
+
+[CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)
diff --git a/dot_hypergraph_to_asymptote.py b/dot_hypergraph_to_asymptote.py
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+#! /usr/bin/env python3
+
+import sys
+import itertools
+import pydot # tested with 1.4.2
+
+if len(sys.argv) != 2:
+    print("Usage: dot_hypergraph_to_asymptote.py <dot file>")
+    sys.exit(1)
+
+# output size
+width = None # 400
+height = 639
+
+# size of node and edge labels
+fontsize = "20pt"
+
+# specify minimum text width
+# (useful if your labels contain wide unicode characters)
+text_width_base = 35 # 40
+text_width_factor = 5.5 # 9
+
+# draw edges reversed
+reverse_edges = True
+
+# output \begin{asy} ... \end{asy}
+output_latex = False
+
+graphs = pydot.graph_from_dot_file(sys.argv[1])
+graph = graphs[0]
+
+nodes = dict()
+node_list = []
+
+for node in graph.get_nodes():
+    pos = node.get_pos()
+    if pos is None:
+        continue
+    pos = pos[1:-1]
+    nodes[node.get_name()] = tuple(map(float, pos.split(",")))
+    node_list.append(node.get_name())
+
+edges = dict()
+
+for edge in graph.get_edges():
+    label = edge.get_label()
+    if label is None:
+        continue
+    label = label.replace('"', "")
+    src = edge.get_source()
+    dest = edge.get_destination()
+    if label not in edges:
+        edges[label] = [(src, dest)]
+    else:
+        edges[label].append((src, dest))
+
+hyperedges = []
+
+for label in edges:
+    xmin = min(itertools.chain(*map(lambda x: [nodes[x[0]][0], nodes[x[1]][0]], edges[label])))
+    xmax = max(itertools.chain(*map(lambda x: [nodes[x[0]][0], nodes[x[1]][0]], edges[label])))
+    ymin = min(map(lambda x: nodes[x[0]][1], edges[label]))
+    ymax = max(map(lambda x: nodes[x[1]][1], edges[label]))
+    x = (xmax + xmin) / 2
+    y = (ymax + ymin) / 2
+    #print(label, xmin, xmax, ymin, ymax, x, y)
+    hyperedges.append(((x, y), label))
+#input("")
+
+if output_latex:
+    print("\\begin{asy}")
+
+# code based on https://tex.stackexchange.com/a/108099/185782 (g.kov)
+
+if width is None:
+    width = 0
+if height is None:
+    height = 0
+print("size(", width, ",", height, ");")
+print("import flowchart;")
+if fontsize is not None:
+    print("defaultpen(fontsize(", fontsize, "));")
+
+print("pair[]pv={")
+
+for node in node_list:
+    print(nodes[node], ",")
+
+print("};")
+
+print("string[]pv_labels={")
+
+for name in node_list:
+    if not name.startswith('"'):
+        name = '"' + name
+    if not name[-1] == '"':
+        name = name + '"'
+    print(name, ',')
+
+print("};")
+
+print("real[]pv_size={")
+
+for node in node_list:
+    print(text_width_base + len(node[1:-1])*text_width_factor, ',')
+
+print("};")
+
+print("pair[][] pe={")
+
+for x in hyperedges:
+    print("{", x[0], ",E},")
+
+print("};")
+
+print("string[] pe_labels={")
+
+for x in hyperedges:
+    print('"', x[1].replace("_", "\\_"), '",')
+
+print("};")
+
+print("""
+pen nodeFill=white;
+pen nodeLine=darkblue+1.2pt+opacity(0.5);
+
+block[] v=new block[pv.length];
+block[] e=new block[pe.length];
+
+
+for(int i=0;i<pv.length;++i){
+  v[i]=rectangle(pv_labels[i],pv[i],nodeFill,nodeLine,minwidth=pv_size[i]);
+  draw(v[i]);
+}
+
+string s;
+for(int i=0;i<pe.length;++i){
+  s=pe_labels[i];
+  e[i]=circle(s,pe[i][0]);
+  label(s,pe[i][0],pe[i][1]);
+  dot(pe[i][0]);
+}
+
+add(
+  new void(picture pic, transform t) {
+    blockconnector operator --=blockconnector(pic,t);
+    real tg;
+     pen linePen=darkblue+1.2pt;
+     currentpen=linePen;
+     arrowfactor=4;
+""")
+
+for n, edge in enumerate(hyperedges):
+    label = edge[1]
+    for e in edges[label]:
+        i1 = node_list.index(e[0])
+        i2 = node_list.index(e[1])
+        if reverse_edges:
+            print("tg=90;")
+            print("draw(pic,v[%d].top(t){dir(90)} .. {dir(tg)}t*e[%d].center{dir(tg)} .. v[%d].bottom(t){dir(90)}, Arrow(HookHead));" % (i2, n, i1))
+        else:
+            print("tg=270;")
+            print("draw(pic,v[%d].bottom(t){dir(270)} .. {dir(tg)}t*e[%d].center{dir(tg)} .. v[%d].top(t){dir(270)},Arrow(HookHead));" % (i1, n, i2))
+
+print("});")
+if output_latex:
+    print("\\end{asy}")
diff --git a/graph.dot b/graph.dot
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+digraph {
+	edge [dir="back"];
+	"Node 1" -> "Node 2" [label="Edge 1"]
+	"Node 1" -> "Node 3" [label="Edge 1"]
+	"Node 3" -> "Node 4" [label="Edge 2"]
+	"Node 3" -> "Node 5" [label="Edge 2"]
+	"Node 5" -> "Node 6" [label="Edge 3"]
+	"Node 4" -> "Node 6" [label="Edge 3"]
+	"Node 2" -> "Node 7" [label="Edge 4"]
+	"Node 6" -> "Node 7" [label="Edge 4"]
+	"Node 2" -> "Node 8" [label="Edge 5"]
+	"Node 7" -> "Node 8" [label="Edge 5"]
+}
\ No newline at end of file
diff --git a/graph.png b/graph.png
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diff --git a/graph_dot.png b/graph_dot.png
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diff --git a/shell.nix b/shell.nix
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+with (import <nixpkgs> {});
+mkShell {
+  nativeBuildInputs = with pkgs; [
+    (python3.withPackages (ps: with ps; [ pydot ]))
+    asymptote
+    texlive.combined.scheme-medium
+  ];
+}