From aeab9c79e6eafd753ed3ad8b2ef2cf4f1f721c88 Mon Sep 17 00:00:00 2001
From: Elodie MORIN <elodie.morin@ensta-bretagne.fr>
Date: Wed, 9 Sep 2026 15:22:42 +0200
Subject: [PATCH] fix(annotator): zoom with mouse scroll should stay centered
 on mouse

---
 .../src/features/Annotator/Canvas/Window.tsx  | 28 +++++++------------
 frontend/src/features/Annotator/Zoom/Root.tsx | 23 +++++++--------
 2 files changed, 20 insertions(+), 31 deletions(-)

diff --git a/frontend/src/features/Annotator/Canvas/Window.tsx b/frontend/src/features/Annotator/Canvas/Window.tsx
index bcd32ab0f..c338345b3 100644
--- a/frontend/src/features/Annotator/Canvas/Window.tsx
+++ b/frontend/src/features/Annotator/Canvas/Window.tsx
@@ -10,7 +10,7 @@ import {
     useTempAnnotationsEvents,
 } from '@/features/Annotator/Annotation';
 import { useWindowContainerWidth, useWindowHeight, useWindowWidth, Y_AXIS_WIDTH } from './window.hooks';
-import { useGetCoords, useGetFreqTime, useIsHoverCanvas, usePointer } from '@/features/Annotator/Pointer';
+import { useGetFreqTime, useIsHoverCanvas, usePointer } from '@/features/Annotator/Pointer';
 import { Zoom } from '@/features/Annotator/Zoom';
 import { useAudio } from '@/features/Audio';
 import { useAnnotatorCanvasContext } from '@/features/Annotator/Canvas/context';
@@ -35,7 +35,6 @@ export const AnnotatorCanvasWindow: React.FC = () => {
     } = useAnnotatorCanvasContext()
     const { onStartTempAnnotation } = useTempAnnotationsEvents()
     const getFreqTime = useGetFreqTime()
-    const getCoords = useGetCoords()
     const {
         zoomLevel,
         zoomType,
@@ -87,11 +86,11 @@ export const AnnotatorCanvasWindow: React.FC = () => {
         // Disable zoom if the user wants horizontal scroll
         if (event.shiftKey) return;
 
-        const origin = getCoords(event);
+        const origin = getFreqTime(event);
         if (!origin) return;
         if (event.deltaY < 0) zoomIn(origin)
         else if (event.deltaY > 0) zoomOut(origin)
-    }, [ zoomIn, zoomOut, getCoords ])
+    }, [ zoomIn, zoomOut, getFreqTime ])
 
     const seekAudio = useCallback((event: MouseEvent<HTMLCanvasElement>) => {
         seek(getFreqTime(event)?.time ?? 0)
@@ -133,7 +132,7 @@ export const AnnotatorCanvasWindow: React.FC = () => {
 
     // Zoom update
     const isHoverCanvas = useIsHoverCanvas()
-    const onZoomUpdated: OnZoomInfoCallback = useCallback(({ previousLevel, level, origin }) => {
+    const onZoomUpdated: OnZoomInfoCallback = useCallback(({ level, origin }) => {
         const mainBounds = interactionCanvasRef?.current?.getBoundingClientRect()
         if (!window || !spectrogram || !mainBounds) return;
 
@@ -143,23 +142,17 @@ export const AnnotatorCanvasWindow: React.FC = () => {
         // Compute new center (before resizing)
         let newCenter: number;
         if (origin) {
-            // x-coordinate has been given, center on it
-            newCenter = (origin.x - mainBounds.left) * level / previousLevel;
-            const coords = {
-                clientX: origin.x,
-                clientY: origin.y,
-            }
-            if (isHoverCanvas(coords)) {
-                const data = getFreqTime(coords);
-                if (data) pointer.setPosition(data)
-            }
+            newCenter = origin.time * newTimePxRatio
         } else {
             // If no x-coordinate: center on currentTime
             newCenter = oldTime.current * newTimePxRatio;
         }
-        window.scrollTo({ left: Math.floor(newCenter - containerWidth / 2) })
+        const left = Math.floor(newCenter - containerWidth / 2)
+        setTimeout(() => requestAnimationFrame(() => {
+            windowCanvasRef?.current?.scrollTo({ left, behavior: 'instant' })
+        }))
         refreshInteractionCanvas()
-    }, [ refreshInteractionCanvas, isHoverCanvas, pointer, getFreqTime, interactionCanvasRef, spectrogram, containerWidth ])
+    }, [ refreshInteractionCanvas, isHoverCanvas, pointer, getFreqTime, interactionCanvasRef, spectrogram, containerWidth, windowCanvasRef ])
     useEffect(() => {
         onZoomUpdatedSignal.add(onZoomUpdated)
         return () => {
@@ -168,7 +161,6 @@ export const AnnotatorCanvasWindow: React.FC = () => {
     }, [ onZoomUpdatedSignal ]);
     useEffect(() => {
         onZoomUpdated({
-            previousLevel: zoomLevel,
             level: zoomLevel,
             type: zoomType,
         })
diff --git a/frontend/src/features/Annotator/Zoom/Root.tsx b/frontend/src/features/Annotator/Zoom/Root.tsx
index 1f1863819..04da2f311 100644
--- a/frontend/src/features/Annotator/Zoom/Root.tsx
+++ b/frontend/src/features/Annotator/Zoom/Root.tsx
@@ -1,13 +1,12 @@
 import React, { createContext, type HTMLProps, useCallback, useContext, useMemo, useState } from 'react';
 import { Signal } from 'signal-ts';
-import type { Point } from '@/service/type';
 import type { CampaignAnalysisFragment, GetCampaignQuery } from '@/features/AnnotationCampaign';
+import type { TimeFreqPosition } from '@/features/Annotator/Pointer';
 
 type ZoomInfo = {
-    previousLevel: number;
     level: number;
     type: 'preprocessed' | 'digital';
-    origin?: Point;
+    origin?: TimeFreqPosition;
 }
 export type OnZoomInfoCallback = (zoomInfo: ZoomInfo) => void;
 
@@ -17,11 +16,11 @@ type ZoomContext = {
 
     canZoomIn: boolean | 'digital';
     zoomInLevel: number | null;
-    zoomIn: (origin?: Point) => void;
+    zoomIn: (origin?: TimeFreqPosition) => void;
 
     canZoomOut: boolean | 'digital';
     zoomOutLevel: number | null;
-    zoomOut: (origin?: Point) => void;
+    zoomOut: (origin?: TimeFreqPosition) => void;
 
     resetZoom: () => void;
 
@@ -100,35 +99,33 @@ export const ZoomRoot: React.FC<Props> = ({ children, campaign, analysis }) => {
         return null
     }, [ zoomLevel ])
 
-    const zoomIn = useCallback((origin?: Point) => {
+    const zoomIn = useCallback((origin?: TimeFreqPosition) => {
+        console.debug('zoomIn', origin)
         if (zoomInLevel === null) return;
         signal.emit({
-            previousLevel: zoomLevel,
             level: zoomInLevel,
             type: zoomInLevel > maxPreProcessedZoomLevel ? 'digital' : 'preprocessed',
             origin,
         })
         setZoomLevel(zoomInLevel)
-    }, [ zoomLevel, zoomInLevel, signal, maxPreProcessedZoomLevel ])
-    const zoomOut = useCallback((origin?: Point) => {
+    }, [ zoomInLevel, signal, maxPreProcessedZoomLevel ])
+    const zoomOut = useCallback((origin?: TimeFreqPosition) => {
         if (zoomOutLevel === null) return;
         signal.emit({
-            previousLevel: zoomLevel,
             level: zoomOutLevel,
             type: zoomOutLevel > maxPreProcessedZoomLevel ? 'digital' : 'preprocessed',
             origin,
         })
         setZoomLevel(zoomOutLevel)
-    }, [ zoomLevel, zoomOutLevel, signal, maxPreProcessedZoomLevel ])
+    }, [ zoomOutLevel, signal, maxPreProcessedZoomLevel ])
 
     const resetZoom = useCallback(() => {
         signal.emit({
-            previousLevel: zoomLevel,
             level: 1,
             type: 'preprocessed',
         })
         setZoomLevel(1)
-    }, [ signal, zoomLevel ])
+    }, [ signal ])
 
     return <ZoomContext.Provider value={ {
         zoomLevel,