From e0005f58ba50ab67f10e5a804cd09a3ee9795348 Mon Sep 17 00:00:00 2001
From: Maxime Vaillancourt <mv@maximevaillancourt.com>
Date: Tue, 21 Jul 2020 21:26:28 -0400
Subject: [PATCH] Add notes graph visualization

---
 _includes/notes_graph.html                | 196 ++++++++++++++++++++++
 _layouts/note.html                        |   5 +
 _pages/index.md                           |   4 +
 _plugins/bidirectional_links_generator.rb |  29 ++++
 4 files changed, 234 insertions(+)
 create mode 100644 _includes/notes_graph.html

diff --git a/_includes/notes_graph.html b/_includes/notes_graph.html
new file mode 100644
index 0000000..48fd09a
--- /dev/null
+++ b/_includes/notes_graph.html
@@ -0,0 +1,196 @@
+<style>
+  .links line {
+    stroke: #ccc;
+    opacity: 0.5;
+  }
+
+  .nodes circle {
+    cursor: pointer;
+    fill: blue;
+    transition: all 0.15s ease-out;
+  }
+
+  .text text {
+    cursor: pointer;
+    fill: #333;
+    text-shadow: -1px -1px 0 #fafafabb, 1px -1px 0 #fafafabb, -1px 1px 0 #fafafabb, 1px 1px 0 #fafafabb;
+  }
+
+  .nodes [active],
+  .text [active] {
+    cursor: pointer;
+    fill: red;
+  }
+
+  .nodes circle[active] {
+    r: 6;
+  }
+
+  #graph-wrapper {
+    background: #fafafa;
+    border-radius: 4px;
+    height: auto;
+  }
+</style>
+
+<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.16.0/d3.min.js"
+  integrity="sha512-FHsFVKQ/T1KWJDGSbrUhTJyS1ph3eRrxI228ND0EGaEp6v4a/vGwPWd3Dtd/+9cI7ccofZvl/wulICEurHN1pg=="
+  crossorigin="anonymous"></script>
+
+<div id="graph-wrapper">
+  <script>
+    const RADIUS = 4;
+    const STROKE = 1;
+    const FONT_SIZE = 15;
+    const TICKS = 100;
+    const FONT_BASELINE = 15;
+    const MAX_LABEL_LENGTH = 50;
+
+    const graphData = {% include notes_graph.json %}
+
+    let nodesData = graphData.nodes;
+    let linksData = graphData.edges;
+
+    const onClick = (d) => {
+      window.location = d.path
+    };
+
+    const element = document.createElementNS(
+      "http://www.w3.org/2000/svg",
+      "svg"
+    );
+    const graphWrapper = document.getElementById('graph-wrapper')
+
+    element.setAttribute("width", graphWrapper.getBoundingClientRect().width);
+    graphWrapper.setAttribute("height", window.innerHeight * 0.8);
+    element.setAttribute("height", window.innerHeight * 0.8);
+
+    graphWrapper.appendChild(element);
+
+    const reportWindowSize = () => {
+      element.setAttribute("width", graphWrapper.getBoundingClientRect().width);
+      graphWrapper.setAttribute("height", window.innerHeight * 0.8);
+      element.setAttribute("height", window.innerHeight * 0.8);
+    };
+
+    window.onresize = reportWindowSize;
+
+    const svg = d3.select("svg");
+    const width = Number(svg.attr("width"));
+    const height = Number(svg.attr("height"));
+    let zoomLevel = 1;
+
+    const simulation = d3
+      .forceSimulation(nodesData)
+      .force("charge", d3
+        .forceManyBody()
+        .strength(-4000)
+      )
+      .force(
+        "link",
+        d3
+          .forceLink(linksData)
+          .id((d) => d.id)
+          .distance(150)
+      )
+      .force("center", d3.forceCenter(width / 2, height / 2))
+      .stop();
+
+    const g = svg.append("g");
+    let link = g.append("g").attr("class", "links").selectAll(".link");
+    let node = g.append("g").attr("class", "nodes").selectAll(".node");
+    let text = g.append("g").attr("class", "text").selectAll(".text");
+
+    const zoomActions = () => {
+      const scale = d3.event.transform;
+      zoomLevel = scale.k;
+      g.attr("transform", scale);
+
+      const zoomOrKeep = (value) => (scale.k >= 1 ? value / scale.k : value);
+
+      const font = Math.max(Math.round(zoomOrKeep(FONT_SIZE)), 1);
+
+      text.attr("font-size", `${font}px`);
+      text.attr("y", (d) => d.y - zoomOrKeep(FONT_BASELINE));
+      link.attr("stroke-width", zoomOrKeep(STROKE));
+      node.attr("r", zoomOrKeep(RADIUS));
+    };
+
+    const ticked = () => {
+      node.attr("cx", (d) => d.x).attr("cy", (d) => d.y);
+      text
+        .attr("x", (d) => d.x)
+        .attr("y", (d) => d.y - FONT_BASELINE / zoomLevel);
+      link
+        .attr("x1", (d) => d.source.x)
+        .attr("y1", (d) => d.source.y)
+        .attr("x2", (d) => d.target.x)
+        .attr("y2", (d) => d.target.y);
+    };
+
+    const restart = () => {
+      node = node.data(nodesData, (d) => d.id);
+      node.exit().remove();
+      node = node
+        .enter()
+        .append("circle")
+        .attr("r", RADIUS)
+        // .attr("fill", (d) => getNodeColor(d))
+        .on("click", onClick)
+        .merge(node);
+
+      link = link.data(linksData, (d) => `${d.source.id}-${d.target.id}`);
+      link.exit().remove();
+      link = link
+        .enter()
+        .append("line")
+        .attr("stroke-width", STROKE)
+        .merge(link);
+
+      node.attr("active", (d) => isCurrentPath(d.path) ? true : null);
+      text.attr("active", (d) => isCurrentPath(d.path) ? true : null);
+
+      text = text.data(nodesData, (d) => d.label);
+      text.exit().remove();
+      text = text
+        .enter()
+        .append("text")
+        .text((d) => shorten(d.label.replace(/_*/g, ""), MAX_LABEL_LENGTH))
+        .attr("font-size", `${FONT_SIZE}px`)
+        .attr("text-anchor", "middle")
+        .attr("alignment-baseline", "central")
+        .on("click", onClick)
+        .merge(text);
+
+      simulation.nodes(nodesData);
+      simulation.force("link").links(linksData);
+      simulation.alpha(1).restart();
+      simulation.stop();
+
+      for (let i = 0; i < TICKS; i++) {
+        simulation.tick();
+      }
+
+      ticked();
+    };
+
+    const zoomHandler = d3
+      .zoom()
+      .scaleExtent([0.2, 3])
+      //.translateExtent([[0,0], [width, height]])
+      //.extent([[0, 0], [width, height]])
+      .on("zoom", zoomActions);
+
+    zoomHandler(svg);
+    restart();
+
+    function isCurrentPath(notePath) {
+      return window.location.pathname.includes(notePath)
+    }
+
+    function shorten(str, maxLen, separator = ' ') {
+      if (str.length <= maxLen) return str;
+      return str.substr(0, str.lastIndexOf(separator, maxLen)) + '...';
+    }
+  </script>
+</div>
diff --git a/_layouts/note.html b/_layouts/note.html
index 0d04671..26a9f3e 100644
--- a/_layouts/note.html
+++ b/_layouts/note.html
@@ -39,3 +39,8 @@ layout: default
   </div>
 </article>
 
+<hr>
+
+<p>Here are all the notes in this garden, along with their links, visualized as a graph.</p>
+
+{% include notes_graph.html %}
diff --git a/_pages/index.md b/_pages/index.md
index 0e2396b..b2ffcca 100644
--- a/_pages/index.md
+++ b/_pages/index.md
@@ -8,3 +8,7 @@ permalink: /
 # Welcome! 🌱
 
 This is your digital garden. Here's [[Your first seed]] to get started on your exploration.
+
+<p>Here are all the notes in this garden, along with their links, visualized as a graph.</p>
+
+{% include notes_graph.html %}
diff --git a/_plugins/bidirectional_links_generator.rb b/_plugins/bidirectional_links_generator.rb
index f6a5a65..87b9fce 100644
--- a/_plugins/bidirectional_links_generator.rb
+++ b/_plugins/bidirectional_links_generator.rb
@@ -1,6 +1,9 @@
 # frozen_string_literal: true
 class BidirectionalLinksGenerator < Jekyll::Generator
   def generate(site)
+    graph_nodes = []
+    graph_edges = []
+
     all_notes = site.collections['notes'].docs
     all_pages = site.pages
 
@@ -19,11 +22,37 @@ class BidirectionalLinksGenerator < Jekyll::Generator
 
     # Identify note backlinks and add them to each note
     all_notes.each do |current_note|
+			# Nodes: Jekyll
       notes_linking_to_current_note = all_notes.filter do |e|
         e.content.include?(current_note.url)
       end
 
+      # Nodes: Graph
+      graph_nodes << {
+        id: note_id_from_note(current_note),
+        path: current_note.url,
+        label: current_note.title,
+      } unless current_note.path.include?('_notes/index.html')
+
+			# Edges: Jekyll
       current_note.data['backlinks'] = notes_linking_to_current_note
+
+      # Edges: Graph
+      notes_linking_to_current_note.each do |n|
+        graph_edges << {
+          source: note_id_from_note(n),
+          target: note_id_from_note(current_note),
+        }
+      end
     end
+
+    File.write('_includes/notes_graph.json', JSON.dump({
+      edges: graph_edges,
+      nodes: graph_nodes,
+    }))
+  end
+
+  def note_id_from_note(note)
+    note.title.to_i(36).to_s
   end
 end