refactor(SVGPanZoom): Fix memory leaking - consolidate zoom lifecycle into PanzoomContainer (open-webui#23236)

* refactor(SVGPanZoom): attach panzoom via use: action and remove unused parent bind:this

* refactor: centralize panzoom in createPanzoomAction and align ImagePreview cleanup

* refactor(panzoom): consolidate zoom lifecycle into PanzoomContainer and remove action-based wiring

Author: ShirasawaSama

src/lib/components/chat/FileNav.svelte

@@ -293,7 +293,6 @@
 	// ── File preview management ──────────────────────────────────────────
 	const clearFilePreview = () => {
 		fileContent = null;
-		filePreviewRef?.disposePanzoom();
 		if (fileImageUrl) {
 			URL.revokeObjectURL(fileImageUrl);
 			fileImageUrl = null;

src/lib/components/chat/FileNav/FilePreview.svelte

@@ -1,13 +1,13 @@
 <script lang="ts">
-	import { getContext, onDestroy, tick } from 'svelte';
-	import panzoom, { type PanZoom } from 'panzoom';
+	import { getContext, tick } from 'svelte';
 	import { marked } from 'marked';
 	import DOMPurify from 'dompurify';
 	import { settings } from '$lib/stores';
 	import { isCodeFile } from '$lib/utils/codeHighlight';
 	import { initMermaid, renderMermaidDiagram } from '$lib/utils';
 	import Spinner from '../../common/Spinner.svelte';
 	import PDFViewer from '../../common/PDFViewer.svelte';
+	import PanzoomContainer from '../../common/PanzoomContainer.svelte';
 	import JsonTreeView from './JsonTreeView.svelte';
 	import NotebookView from './NotebookView.svelte';
 	import SqliteView from './SqliteView.svelte';
@@ -250,38 +250,14 @@
 		showRaw = true;
 	}
 
-	let pzInstance: PanZoom | null = null;
-
-	const initImagePanzoom = (node: HTMLElement) => {
-		pzInstance = panzoom(node, {
-			bounds: true,
-			boundsPadding: 0.1,
-			zoomSpeed: 0.065,
-			zoomDoubleClickSpeed: 1
-		});
-	};
-
+	let panzoomRef: PanzoomContainer;
 	export const resetImageView = () => {
-		if (pzInstance) {
-			pzInstance.moveTo(0, 0);
-			pzInstance.zoomAbs(0, 0, 1);
-		}
-	};
-
-	export const disposePanzoom = () => {
-		if (pzInstance) {
-			pzInstance.dispose();
-			pzInstance = null;
-		}
+		panzoomRef?.reset();
 	};
 
 	export const resetPdfView = () => {
 		pdfViewerRef?.resetView();
 	};
-
-	onDestroy(() => {
-		disposePanzoom();
-	});
 </script>
 
 <div
@@ -293,14 +269,18 @@
 	{#if fileLoading}
 		<div class="flex items-center justify-center h-full"><Spinner className="size-4" /></div>
 	{:else if fileImageUrl !== null}
-		<div class="w-full h-full flex items-center justify-center" use:initImagePanzoom>
+		<PanzoomContainer
+			bind:this={panzoomRef}
+			className="w-full h-full flex items-center justify-center"
+			options={{ zoomDoubleClickSpeed: 1 }}
+		>
 			<img
 				src={fileImageUrl}
 				alt={selectedFile?.split('/').pop()}
 				class="max-w-full max-h-full object-contain p-3"
 				draggable="false"
 			/>
-		</div>
+		</PanzoomContainer>
 	{:else if fileVideoUrl !== null}
 		<div class="w-full h-full flex items-center justify-center bg-black">
 			<!-- svelte-ignore a11y-media-has-caption -->
@@ -343,17 +323,18 @@
 		</div>
 	{:else if fileOfficeSlides !== null && fileOfficeSlides.length > 0}
 		<div class="flex flex-col h-full">
-			<div
-				class="w-full flex-1 min-h-0 flex items-center justify-center overflow-hidden"
-				use:initImagePanzoom
+			<PanzoomContainer
+				bind:this={panzoomRef}
+				className="w-full flex-1 min-h-0 flex items-center justify-center overflow-hidden"
+				options={{ zoomDoubleClickSpeed: 1 }}
 			>
 				<img
 					src={fileOfficeSlides[currentSlide]}
 					alt="Slide {currentSlide + 1}"
 					class="max-w-full max-h-full object-contain p-3"
 					draggable="false"
 				/>
-			</div>
+			</PanzoomContainer>
 			{#if fileOfficeSlides.length > 1}
 				<div
 					class="flex items-center justify-center gap-3 py-2 px-3 border-t border-gray-100 dark:border-gray-800 text-xs text-gray-500"

src/lib/components/common/FileItemModal.svelte

@@ -25,9 +25,9 @@
 	import dayjs from 'dayjs';
 	import Spinner from './Spinner.svelte';
 	import PDFViewer from './PDFViewer.svelte';
+	import PanzoomContainer from './PanzoomContainer.svelte';
 	import Reset from '../icons/Reset.svelte';
 
-	import panzoom, { type PanZoom } from 'panzoom';
 
 	export let item;
 	export let show = false;
@@ -60,21 +60,9 @@
 	let pptxCurrentSlide = 0;
 	let pptxError = '';
 
-	let pzInstance: PanZoom | null = null;
-
-	const initImagePanzoom = (node: HTMLElement) => {
-		pzInstance = panzoom(node, {
-			bounds: true,
-			boundsPadding: 0.1,
-			zoomSpeed: 0.065
-		});
-	};
-
+	let panzoomRef: PanzoomContainer;
 	const resetImageView = () => {
-		if (pzInstance) {
-			pzInstance.moveTo(0, 0);
-			pzInstance.zoomAbs(0, 0, 1);
-		}
+		panzoomRef?.reset();
 	};
 
 	$: isPDF =
@@ -266,10 +254,6 @@
 		if (item?.context === 'full') {
 			enableFullContent = true;
 		}
-
-		return () => {
-			pzInstance?.dispose();
-		};
 	});
 </script>
 
@@ -445,15 +429,15 @@
 								</button>
 							</Tooltip>
 						</div>
-						<div use:initImagePanzoom>
+						<PanzoomContainer bind:this={panzoomRef}>
 							<img
 								src={`${WEBUI_API_BASE_URL}/files/${item.id}/content`}
 								alt={item?.name ?? 'Image'}
 								class="w-full object-contain rounded-lg"
 								loading="lazy"
 								draggable="false"
 							/>
-						</div>
+						</PanzoomContainer>
 					</div>
 				{:else if selectedTab === ''}
 					{#if item?.file?.data}

src/lib/components/common/ImagePreview.svelte

@@ -1,10 +1,10 @@
 <script lang="ts">
-	import { onDestroy, onMount, getContext } from 'svelte';
-	import panzoom, { type PanZoom } from 'panzoom';
+	import { onDestroy, getContext } from 'svelte';
 
 	import fileSaver from 'file-saver';
 	const { saveAs } = fileSaver;
 
+	import PanzoomContainer from '$lib/components/common/PanzoomContainer.svelte';
 	import XMark from '$lib/components/icons/XMark.svelte';
 
 	export let show = false;
@@ -13,40 +13,15 @@
 
 	const i18n = getContext('i18n');
 
-	let mounted = false;
-
 	let previewElement = null;
 
-	let instance: PanZoom;
-
-	let sceneParentElement: HTMLElement;
-	let sceneElement: HTMLElement;
-
-	$: if (sceneElement) {
-		instance = panzoom(sceneElement, {
-			bounds: true,
-			boundsPadding: 0.1,
-
-			zoomSpeed: 0.065
-		});
-	}
-	const resetPanZoomViewport = () => {
-		instance.moveTo(0, 0);
-		instance.zoomAbs(0, 0, 1);
-		console.log(instance.getTransform());
-	};
-
 	const handleKeyDown = (event: KeyboardEvent) => {
 		if (event.key === 'Escape') {
 			console.log('Escape');
 			show = false;
 		}
 	};
 
-	onMount(() => {
-		mounted = true;
-	});
-
 	$: if (show && previewElement) {
 		document.body.appendChild(previewElement);
 		window.addEventListener('keydown', handleKeyDown);
@@ -58,11 +33,15 @@
 	}
 
 	onDestroy(() => {
+		window.removeEventListener('keydown', handleKeyDown);
 		show = false;
 
-		if (previewElement) {
+		if (previewElement && previewElement.parentNode === document.body) {
 			document.body.removeChild(previewElement);
 		}
+		// NOTE: If multiple modals can stack in the future, direct "unset" may
+		// re-enable page scroll too early. Consider a shared body-scroll lock manager.
+		document.body.style.overflow = 'unset';
 	});
 </script>
 
@@ -181,14 +160,13 @@
 				</button>
 			</div>
 		</div>
-		<div class="flex h-full max-h-full justify-center items-center z-0">
+		<PanzoomContainer className="flex h-full max-h-full justify-center items-center z-0">
 			<img
-				bind:this={sceneElement}
 				{src}
 				{alt}
 				class=" mx-auto h-full object-scale-down select-none"
 				draggable="false"
 			/>
-		</div>
+		</PanzoomContainer>
 	</div>
 {/if}

src/lib/components/common/PanzoomContainer.svelte

@@ -0,0 +1,33 @@
+<script lang="ts">
+	import { onMount } from 'svelte';
+	import panzoom, { type PanZoom, type PanZoomOptions } from 'panzoom';
+
+	const defaultOpts: PanZoomOptions = {
+		bounds: true,
+		boundsPadding: 0.1,
+		zoomSpeed: 0.065
+	};
+
+	export let className = '';
+	export let options: Partial<PanZoomOptions> = {};
+
+	let containerElement: HTMLElement;
+	let instance: PanZoom | undefined;
+
+	export const reset = () => {
+		instance?.moveTo(0, 0);
+		instance?.zoomAbs(0, 0, 1);
+	};
+
+	onMount(() => {
+		const localInstance = panzoom(containerElement, { ...defaultOpts, ...options });
+		instance = localInstance;
+		return () => {
+			localInstance.dispose();
+		}
+	});
+</script>
+
+<div bind:this={containerElement} class={className}>
+	<slot />
+</div>

src/lib/components/common/SVGPanZoom.svelte

@@ -4,15 +4,14 @@
 
 	import { toast } from 'svelte-sonner';
 
-	import panzoom, { type PanZoom } from 'panzoom';
 	import DOMPurify from 'dompurify';
 
-	import { onMount, getContext } from 'svelte';
+	import { getContext } from 'svelte';
 	const i18n = getContext('i18n');
 
 	import { copyToClipboard } from '$lib/utils';
 
-	import DocumentDuplicate from '../icons/DocumentDuplicate.svelte';
+	import PanzoomContainer from './PanzoomContainer.svelte';
 	import Tooltip from './Tooltip.svelte';
 	import Clipboard from '../icons/Clipboard.svelte';
 	import Reset from '../icons/Reset.svelte';
@@ -22,23 +21,9 @@
 	export let svg = '';
 	export let content = '';
 
-	let instance: PanZoom;
-
-	let sceneParentElement: HTMLElement;
-	let sceneElement: HTMLElement;
-
-	$: if (sceneElement) {
-		instance = panzoom(sceneElement, {
-			bounds: true,
-			boundsPadding: 0.1,
-
-			zoomSpeed: 0.065
-		});
-	}
+	let panzoomRef: PanzoomContainer;
 	const resetPanZoomViewport = () => {
-		instance.moveTo(0, 0);
-		instance.zoomAbs(0, 0, 1);
-		console.log(instance.getTransform());
+		panzoomRef?.reset();
 	};
 
 	const downloadAsSVG = () => {
@@ -47,8 +32,11 @@
 	};
 </script>
 
-<div bind:this={sceneParentElement} class="relative {className}">
-	<div bind:this={sceneElement} class="flex h-full max-h-full justify-center items-center">
+<div class="relative {className}">
+	<PanzoomContainer
+		bind:this={panzoomRef}
+		className="flex h-full max-h-full justify-center items-center"
+	>
 		{@html DOMPurify.sanitize(svg, {
 			USE_PROFILES: { svg: true, svgFilters: true }, // allow <svg>, <defs>, <filter>, etc.
 			WHOLE_DOCUMENT: false,
@@ -88,7 +76,7 @@
 			],
 			SANITIZE_DOM: true
 		})}
-	</div>
+	</PanzoomContainer>
 
 	{#if content}
 		<div class=" absolute top-2.5 right-2.5">