From 4cce842950d1fa1cc9d35da7541f3ee14d24fdff Mon Sep 17 00:00:00 2001
From: Kristóf Marussy <kristof@marussy.com>
Date: Wed, 23 Aug 2023 11:48:37 +0200
Subject: refactor: d3 zoom centering

Uses patch from https://github.com/d3/d3-zoom/pull/212
---
 package.json                                 |  3 +
 subprojects/frontend/src/graph/GraphArea.tsx | 83 +++++++++-------------------
 yarn.lock                                    | 33 ++++++-----
 3 files changed, 48 insertions(+), 71 deletions(-)

diff --git a/package.json b/package.json
index 5515a3cd..bdac68a6 100644
--- a/package.json
+++ b/package.json
@@ -27,5 +27,8 @@
   "devDependencies": {
     "eslint": "^8.47.0",
     "typescript": "5.1.6"
+  },
+  "resolutions": {
+    "d3-zoom@npm:^3.0.0": "git@github.com:d3/d3-zoom.git#commit=3afbe2ae2dfb3129231c5567db56dafb2d6a56a6"
   }
 }
diff --git a/subprojects/frontend/src/graph/GraphArea.tsx b/subprojects/frontend/src/graph/GraphArea.tsx
index b55245d8..1da7eaef 100644
--- a/subprojects/frontend/src/graph/GraphArea.tsx
+++ b/subprojects/frontend/src/graph/GraphArea.tsx
@@ -8,9 +8,9 @@ import Box from '@mui/material/Box';
 import * as d3 from 'd3';
 import { type Graphviz, graphviz } from 'd3-graphviz';
 import type { BaseType, Selection } from 'd3-selection';
+import { zoom as d3Zoom } from 'd3-zoom';
 import { reaction, type IReactionDisposer } from 'mobx';
 import { useCallback, useRef, useState } from 'react';
-import { useResizeDetector } from 'react-resize-detector';
 
 import { useRootStore } from '../RootStoreProvider';
 import type { SemanticsSuccessResult } from '../xtext/xtextServiceResults';
@@ -88,59 +88,30 @@ export default function GraphArea(): JSX.Element {
     d3.ZoomBehavior<HTMLDivElement, unknown> | undefined
   >();
   const [zoom, setZoom] = useState<Transform>({ x: 0, y: 0, k: 1 });
-  const widthRef = useRef<number | undefined>();
-  const heightRef = useRef<number | undefined>();
 
-  const onResize = useCallback(
-    (width: number | undefined, height: number | undefined) => {
-      if (canvasRef.current === undefined || zoomRef.current === undefined) {
-        return;
-      }
-      let moveX = 0;
-      let moveY = 0;
-      if (widthRef.current !== undefined && width !== undefined) {
-        moveX = (width - widthRef.current) / 2;
-      }
-      if (heightRef.current !== undefined && height !== undefined) {
-        moveY = (height - heightRef.current) / 2;
-      }
-      widthRef.current = width;
-      heightRef.current = height;
-      if (moveX === 0 && moveY === 0) {
-        return;
-      }
-      const currentTransform = d3.zoomTransform(canvasRef.current);
-      zoomRef.current.translateBy(
-        d3.select(canvasRef.current),
-        moveX / currentTransform.k - moveX,
-        moveY / currentTransform.k - moveY,
-      );
-    },
-    [],
-  );
-
-  const { ref: setCanvasResize } = useResizeDetector({
-    onResize,
-  });
-
-  const setCanvas = useCallback(
-    (element: HTMLDivElement | null) => {
-      canvasRef.current = element ?? undefined;
-      setCanvasResize(element);
-      if (element === null) {
-        return;
+  const setCanvas = useCallback((element: HTMLDivElement | null) => {
+    canvasRef.current = element ?? undefined;
+    if (element === null) {
+      return;
+    }
+    const zoomBehavior = d3Zoom<HTMLDivElement, unknown>();
+    // `@types/d3-zoom` does not contain the `center` function, because it is
+    // only available as a pull request for `d3-zoom`.
+    (
+      zoomBehavior as unknown as {
+        center(callback: (event: MouseEvent) => [number, number]): unknown;
       }
-      const zoomBehavior = d3.zoom<HTMLDivElement, unknown>();
-      zoomBehavior.on(
-        'zoom',
-        (event: d3.D3ZoomEvent<HTMLDivElement, unknown>) =>
-          setZoom(event.transform),
-      );
-      d3.select(element).call(zoomBehavior);
-      zoomRef.current = zoomBehavior;
-    },
-    [setCanvasResize],
-  );
+    ).center((event: MouseEvent) => {
+      const { width, height } = element.getBoundingClientRect();
+      const [x, y] = d3.pointer(event, element);
+      return [x - width / 2, y - height / 2];
+    });
+    zoomBehavior.on('zoom', (event: d3.D3ZoomEvent<HTMLDivElement, unknown>) =>
+      setZoom(event.transform),
+    );
+    d3.select(element).call(zoomBehavior);
+    zoomRef.current = zoomBehavior;
+  }, []);
 
   const setElement = useCallback(
     (element: HTMLDivElement | null) => {
@@ -210,8 +181,8 @@ export default function GraphArea(): JSX.Element {
                 rect.setAttribute('width', String(xmax - xmin));
                 rect.setAttribute('height', String(ymax - ymin));
                 rect.setAttribute('height', String(ymax - ymin));
-                rect.setAttribute('rx', '12');
-                rect.setAttribute('ry', '12');
+                rect.setAttribute('rx', '8');
+                rect.setAttribute('ry', '8');
                 node.replaceChild(rect, path);
               });
             });
@@ -302,8 +273,8 @@ export default function GraphArea(): JSX.Element {
       <Box
         sx={{
           position: 'absolute',
-          top: `${50 * zoom.k}%`,
-          left: `${50 * zoom.k}%`,
+          top: '50%',
+          left: '50%',
           transform: `
               translate(${zoom.x}px, ${zoom.y}px)
               scale(${zoom.k})
diff --git a/yarn.lock b/yarn.lock
index b1d7b9d6..2101a994 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2663,13 +2663,13 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/d3-zoom@npm:*":
-  version: 3.0.3
-  resolution: "@types/d3-zoom@npm:3.0.3"
+"@types/d3-zoom@npm:*, @types/d3-zoom@npm:^3.0.4":
+  version: 3.0.4
+  resolution: "@types/d3-zoom@npm:3.0.4"
   dependencies:
     "@types/d3-interpolate": "npm:*"
     "@types/d3-selection": "npm:*"
-  checksum: 7b48870cadf18ba1104613605fc6157dc230f71ecac7f2f0d7e689b44a62ab29377edf98e935a6eee8b87c32456effe3cf6aab321cc20bb31695d21f62fdb311
+  checksum: 52d1b5f2a1490c25c69b03dcd71601f908ea1e3dedf79e379be4ff23e3a6be85d0694d04c1b23686343a74117e86683a61433ed926637aea545268fd55aa634f
   languageName: node
   linkType: hard
 
@@ -2683,16 +2683,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/d3-zoom@npm:^3.0.4":
-  version: 3.0.4
-  resolution: "@types/d3-zoom@npm:3.0.4"
-  dependencies:
-    "@types/d3-interpolate": "npm:*"
-    "@types/d3-selection": "npm:*"
-  checksum: 52d1b5f2a1490c25c69b03dcd71601f908ea1e3dedf79e379be4ff23e3a6be85d0694d04c1b23686343a74117e86683a61433ed926637aea545268fd55aa634f
-  languageName: node
-  linkType: hard
-
 "@types/d3@npm:^7.4.0":
   version: 7.4.0
   resolution: "@types/d3@npm:7.4.0"
@@ -4154,7 +4144,20 @@ __metadata:
   languageName: node
   linkType: hard
 
-"d3-zoom@npm:3, d3-zoom@npm:^3.0.0":
+"d3-zoom@git@github.com:d3/d3-zoom.git#commit=3afbe2ae2dfb3129231c5567db56dafb2d6a56a6":
+  version: 3.0.0
+  resolution: "d3-zoom@git@github.com:d3/d3-zoom.git#commit=3afbe2ae2dfb3129231c5567db56dafb2d6a56a6"
+  dependencies:
+    d3-dispatch: "npm:1 - 3"
+    d3-drag: "npm:2 - 3"
+    d3-interpolate: "npm:1 - 3"
+    d3-selection: "npm:2 - 3"
+    d3-transition: "npm:2 - 3"
+  checksum: 0cca9382fd9cf7383ecd89ae2f4a828b5088e7801eb89da0656c1d3512cda03bfade727db936721b8004a3142dbbf955a408c99cf370539e3a985da9161c6d54
+  languageName: node
+  linkType: hard
+
+"d3-zoom@npm:3":
   version: 3.0.0
   resolution: "d3-zoom@npm:3.0.0"
   dependencies:
-- 
cgit v1.2.3-54-g00ecf