From cec3662c748ff6abbe8570632e9287085a2a51fc Mon Sep 17 00:00:00 2001
From: Aaron Pham <29749331+aarnphm@users.noreply.github.com>
Date: Mon, 4 Mar 2024 15:09:20 -0500
Subject: [PATCH] feat(graph): focusOnHover (#954)

by default, globalGraph will enable focusOnHover, similar to Obsidian.

---------

Signed-off-by: Aaron <29749331+aarnphm@users.noreply.github.com>
---
 quartz/components/Graph.tsx               |  3 +++
 quartz/components/scripts/graph.inline.ts | 27 ++++++++++++++++++-----
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/quartz/components/Graph.tsx b/quartz/components/Graph.tsx
index 40ab43a2d..f7ebcc9a2 100644
--- a/quartz/components/Graph.tsx
+++ b/quartz/components/Graph.tsx
@@ -17,6 +17,7 @@ export interface D3Config {
   opacityScale: number
   removeTags: string[]
   showTags: boolean
+  focusOnHover?: boolean
 }
 
 interface GraphOptions {
@@ -37,6 +38,7 @@ const defaultOptions: GraphOptions = {
     opacityScale: 1,
     showTags: true,
     removeTags: [],
+    focusOnHover: false,
   },
   globalGraph: {
     drag: true,
@@ -50,6 +52,7 @@ const defaultOptions: GraphOptions = {
     opacityScale: 1,
     showTags: true,
     removeTags: [],
+    focusOnHover: true,
   },
 }
 
diff --git a/quartz/components/scripts/graph.inline.ts b/quartz/components/scripts/graph.inline.ts
index c991e163e..1c9bb5d64 100644
--- a/quartz/components/scripts/graph.inline.ts
+++ b/quartz/components/scripts/graph.inline.ts
@@ -44,6 +44,7 @@ async function renderGraph(container: string, fullSlug: FullSlug) {
     opacityScale,
     removeTags,
     showTags,
+    focusOnHover,
   } = JSON.parse(graph.dataset["cfg"]!)
 
   const data: Map<SimpleSlug, ContentDetails> = new Map(
@@ -189,6 +190,8 @@ async function renderGraph(container: string, fullSlug: FullSlug) {
     return 2 + Math.sqrt(numLinks)
   }
 
+  let connectedNodes: SimpleSlug[] = []
+
   // draw individual nodes
   const node = graphNode
     .append("circle")
@@ -202,17 +205,25 @@ async function renderGraph(container: string, fullSlug: FullSlug) {
       window.spaNavigate(new URL(targ, window.location.toString()))
     })
     .on("mouseover", function (_, d) {
-      const neighbours: SimpleSlug[] = data.get(slug)?.links ?? []
-      const neighbourNodes = d3
-        .selectAll<HTMLElement, NodeData>(".node")
-        .filter((d) => neighbours.includes(d.id))
       const currentId = d.id
       const linkNodes = d3
         .selectAll(".link")
         .filter((d: any) => d.source.id === currentId || d.target.id === currentId)
 
-      // highlight neighbour nodes
-      neighbourNodes.transition().duration(200).attr("fill", color)
+      if (focusOnHover) {
+        // fade out non-neighbour nodes
+        connectedNodes = linkNodes.data().flatMap((d: any) => [d.source.id, d.target.id])
+
+        d3.selectAll<HTMLElement, NodeData>(".link")
+          .transition()
+          .duration(200)
+          .style("opacity", 0.2)
+        d3.selectAll<HTMLElement, NodeData>(".node")
+          .filter((d) => !connectedNodes.includes(d.id))
+          .transition()
+          .duration(200)
+          .style("opacity", 0.2)
+      }
 
       // highlight links
       linkNodes.transition().duration(200).attr("stroke", "var(--gray)").attr("stroke-width", 1)
@@ -231,6 +242,10 @@ async function renderGraph(container: string, fullSlug: FullSlug) {
         .style("font-size", bigFont + "em")
     })
     .on("mouseleave", function (_, d) {
+      if (focusOnHover) {
+        d3.selectAll<HTMLElement, NodeData>(".link").transition().duration(200).style("opacity", 1)
+        d3.selectAll<HTMLElement, NodeData>(".node").transition().duration(200).style("opacity", 1)
+      }
       const currentId = d.id
       const linkNodes = d3
         .selectAll(".link")