add base structure

layouts/partials/graph.html

@@ -0,0 +1,218 @@
+<script src="https://cdn.jsdelivr.net/npm/d3@6"></script>
+<div id="graph-container"></div>
+<style>
+    :root {
+        --g-node: {{.Site.Data.graphConfig.base.node}};
+        --g-node-active: {{.Site.Data.graphConfig.base.activeNode}};
+        --g-node-inactive: {{.Site.Data.graphConfig.base.inactiveNode}};
+        --g-link: {{.Site.Data.graphConfig.base.link}};
+        --g-link-active: {{.Site.Data.graphConfig.base.activeLink}};
+    }
+</style>
+<script>
+  const index = {{$.Site.Data.linkIndex.index}}
+  const links = {{$.Site.Data.linkIndex.links}}
+  const curPage = {{ strings.TrimRight "/" .Page.RelPermalink }}
+  const pathColors = {{$.Site.Data.graphConfig.paths}}
+
+  const parseIdsFromLinks = (links) => [...(new Set(links.flatMap(link => ([link.source, link.target]))))]
+
+  const data = {
+    nodes: parseIdsFromLinks(links).map(id => ({id})),
+    links,
+  }
+
+  const color = (d) => {
+    if (d.id === curPage) {
+      return "var(--g-node-active)"
+    }
+
+    for (const pathColor of pathColors) {
+      const path = Object.keys(pathColor)[0]
+      const colour = pathColor[path]
+      if (d.id.startsWith(path)) {
+        return colour
+      }
+    }
+
+    return "var(--g-node)"
+  }
+
+  const drag = simulation => {
+    function dragstarted(event, d) {
+      if (!event.active) simulation.alphaTarget(1).restart();
+      d.fx = d.x;
+      d.fy = d.y;
+    }
+
+    function dragged(event,d) {
+      d.fx = event.x;
+      d.fy = event.y;
+    }
+
+    function dragended(event,d) {
+      if (!event.active) simulation.alphaTarget(0);
+      d.fx = null;
+      d.fy = null;
+    }
+
+    const enableDrag = {{$.Site.Data.graphConfig.enableDrag}}
+    const noop = () => {}
+    return d3.drag()
+      .on("start", enableDrag ? dragstarted : noop)
+      .on("drag", enableDrag ? dragged : noop)
+      .on("end", enableDrag ? dragended : noop);
+  }
+
+  const height = 400
+  const width = document.getElementById("graph-container").offsetWidth
+
+  const simulation = d3.forceSimulation(data.nodes)
+    .force("charge", d3.forceManyBody().strength(-20))
+    .force("link", d3.forceLink(data.links)
+      .id(d => d.id)
+    )
+    .force("center", d3.forceCenter());
+
+  const svg = d3.select('#graph-container')
+    .append('svg')
+    .attr('width', width)
+    .attr('height', height)
+    .attr("viewBox", [-width / 2, -height / 2, width, height]);
+
+  // legend
+  const enableLegend = {{$.Site.Data.graphConfig.enableLegend}}
+  if (enableLegend) {
+    const legend = [
+      {"Current": "var(--g-node-active)"},
+      {"Note": "var(--g-node)"},
+      ...pathColors
+    ]
+    legend.forEach((legendEntry, i) => {
+      const key = Object.keys(legendEntry)[0]
+      const colour = legendEntry[key]
+      svg.append("circle").attr("cx", -width/2 + 20).attr("cy", height/2 - 30 * (i+1)).attr("r", 6).style("fill", colour)
+      svg.append("text").attr("x", -width/2 + 40).attr("y", height/2 - 30 * (i+1)).text(key).style("font-size", "15px").attr("alignment-baseline","middle")
+    })
+  }
+
+  // draw links between nodes
+  const link = svg.append("g")
+    .selectAll("line")
+    .data(data.links)
+    .join("line")
+    .attr("class", "link")
+    .attr("stroke", "var(--g-link)")
+    .attr("stroke-width", 2)
+    .attr("data-source", d => d.source.id)
+    .attr("data-target", d => d.target.id)
+
+  // svg groups
+  const graphNode = svg.append("g")
+    .selectAll("g")
+    .data(data.nodes)
+    .enter().append("g")
+
+  // draw individual nodes
+  const node = graphNode.append("circle")
+    .attr("class", "node")
+    .attr("id", (d) => d.id)
+    .attr("r", (d) => {
+      const numOut = index.links[d.id]?.length || 0
+      const numIn = index.backlinks[d.id]?.length || 0
+      return 3 + (numOut + numIn) / 4
+    })
+    .attr("fill", color)
+    .style("cursor", "pointer")
+    .on("click", (_, d) => {
+      window.location.href = d.id;
+    })
+    .on("mouseover", function (_, d) {
+      d3.selectAll(".node")
+        .transition()
+        .duration(100)
+        .attr("fill", "var(--g-node-inactive)")
+
+      const neighbours = parseIdsFromLinks([...(index.links[d.id] || []), ...(index.backlinks[d.id] || [])])
+      const neighbourNodes = d3.selectAll(".node").filter(d => neighbours.includes(d.id))
+      const currentId = d.id
+      const links = d3.selectAll(".link").filter(d => d.source.id === currentId || d.target.id === currentId)
+
+      // highlight neighbour nodes
+      neighbourNodes
+        .transition()
+        .duration(200)
+        .attr("fill", color)
+
+      // highlight links
+      links
+        .transition()
+        .duration(200)
+        .attr("stroke", "var(--g-link-active)")
+
+      // show text for self
+      d3.select(this.parentNode)
+        .select("text")
+        .raise()
+        .transition()
+        .duration(200)
+        .style("opacity", 1)
+    }).on("mouseleave", function (_,d) {
+      d3.selectAll(".node")
+        .transition()
+        .duration(200)
+        .attr("fill", color)
+
+      const currentId = d.id
+      const links = d3.selectAll(".link").filter(d => d.source.id === currentId || d.target.id === currentId)
+
+      links
+        .transition()
+        .duration(200)
+        .attr("stroke", "var(--g-link)")
+
+      d3.select(this.parentNode)
+        .select("text")
+        .transition()
+        .duration(200)
+        .style("opacity", 0)
+    })
+    .call(drag(simulation));
+
+  // draw labels
+  const labels = graphNode.append("text")
+    .attr("dx", 12)
+    .attr("dy", ".35em")
+    .text((d) => d.id)
+    .style("opacity", 0)
+    .style("pointer-events", "none")
+    .call(drag(simulation));
+
+  // set panning
+  const enableZoom = {{$.Site.Data.graphConfig.enableZoom}}
+  if (enableZoom) {
+    svg.call(d3.zoom()
+      .extent([[0, 0], [width, height]])
+      .scaleExtent([0.25, 4])
+      .on("zoom", ({transform}) => {
+        link.attr("transform", transform);
+        node.attr("transform", transform);
+        labels.attr("transform", transform);
+      }));
+  }
+
+  // progress the simulation
+  simulation.on("tick", () => {
+    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);
+    node
+      .attr("cx", d => d.x)
+      .attr("cy", d => d.y);
+    labels
+      .attr("x", d => d.x)
+      .attr("y", d => d.y);
+  });
+</script>