feat(web): add zoom minimap preview overlay

web/src/lib/actions/zoom-image.ts

@@ -1,4 +1,5 @@
 import { assetViewerManager } from '$lib/managers/asset-viewer-manager.svelte';
+import type { ZoomImageWheelState } from '@zoom-image/core';
 import { createZoomImageWheel } from '@zoom-image/core';
 
 type TouchEventLike = {
@@ -7,22 +8,66 @@ type TouchEventLike = {
 };
 const asTouchEvent = (event: Event) => event as unknown as TouchEventLike;
 
+export const MAX_ZOOM = 10;
+
 export const zoomImageAction = (node: HTMLElement, options?: { zoomTarget?: HTMLElement }) => {
-  const zoomInstance = createZoomImageWheel(node, {
-    maxZoom: 10,
+  let zoomInstance = createZoomImageWheel(node, {
+    maxZoom: MAX_ZOOM,
     initialState: assetViewerManager.zoomState,
     zoomTarget: options?.zoomTarget,
   });
 
-  const unsubscribes = [
-    assetViewerManager.on({ ZoomChange: (state) => zoomInstance.setState(state) }),
-    zoomInstance.subscribe(({ state }) => assetViewerManager.onZoomChange(state)),
-  ];
+  let needsResync = false;
+
+  const createInstance = () => {
+    zoomInstance.cleanup();
+    zoomInstance = createZoomImageWheel(node, {
+      maxZoom: MAX_ZOOM,
+      initialState: { ...assetViewerManager.zoomState, enable: true },
+      zoomTarget: options?.zoomTarget,
+    });
+    node.style.overflow = 'visible';
+    unsubscribeStore?.();
+    unsubscribeStore = zoomInstance.subscribe(({ state }) => assetViewerManager.onZoomChange(state));
+    needsResync = false;
+  };
+
+  const applyDirectTransform = (state: ZoomImageWheelState) => {
+    const target = options?.zoomTarget ?? node.querySelector('img');
+    if (target) {
+      (target as HTMLElement).style.transformOrigin = '0 0';
+      (target as HTMLElement).style.transform =
+        `translate(${state.currentPositionX}px, ${state.currentPositionY}px) scale(${state.currentZoom})`;
+      needsResync = true;
+    }
+  };
+
+  const resyncIfNeeded = () => {
+    if (needsResync) {
+      createInstance();
+    }
+  };
+
+  let unsubscribeStore = zoomInstance.subscribe(({ state }) => assetViewerManager.onZoomChange(state));
+
+  const unsubscribeManager = assetViewerManager.on({
+    ZoomChange: (state) => zoomInstance.setState(state),
+    DirectTransform: (state) => applyDirectTransform(state),
+    ZoomEnabled: (enabled) => {
+      if (enabled && needsResync) {
+        createInstance();
+      } else {
+        zoomInstance.setState({ enable: enabled });
+      }
+    },
+  });
 
   const controller = new AbortController();
   const { signal } = controller;
 
   node.addEventListener('pointerdown', () => assetViewerManager.cancelZoomAnimation(), { capture: true, signal });
+  node.addEventListener('pointerdown', resyncIfNeeded, { signal });
+  node.addEventListener('wheel', resyncIfNeeded, { signal });
 
   // Intercept events in capture phase to prevent zoom-image from seeing interactions on
   // overlay elements (e.g. OCR text boxes), preserving browser defaults like text selection.
@@ -134,9 +179,8 @@ export const zoomImageAction = (node: HTMLElement, options?: { zoomTarget?: HTML
     },
     destroy() {
       controller.abort();
-      for (const unsubscribe of unsubscribes) {
-        unsubscribe();
-      }
+      unsubscribeManager();
+      unsubscribeStore?.();
       zoomInstance.cleanup();
     },
   };

web/src/lib/components/asset-viewer/photo-viewer.svelte

@@ -5,6 +5,7 @@
   import AdaptiveImage from '$lib/components/AdaptiveImage.svelte';
   import FaceEditor from '$lib/components/asset-viewer/face-editor/face-editor.svelte';
   import OcrBoundingBox from '$lib/components/asset-viewer/ocr-bounding-box.svelte';
+  import ZoomMinimap from '$lib/components/asset-viewer/zoom-minimap.svelte';
   import AssetViewerEvents from '$lib/components/AssetViewerEvents.svelte';
   import { assetViewerManager } from '$lib/managers/asset-viewer-manager.svelte';
   import { castManager } from '$lib/managers/cast-manager.svelte';
@@ -255,6 +256,8 @@
     {/snippet}
   </AdaptiveImage>
 
+  <ZoomMinimap {containerWidth} {containerHeight} {asset} {sharedLink} />
+
   {#if isFaceEditMode.value && assetViewerManager.imgRef}
     <FaceEditor htmlElement={assetViewerManager.imgRef} {containerWidth} {containerHeight} assetId={asset.id} />
   {/if}

web/src/lib/components/asset-viewer/zoom-minimap.svelte

@@ -0,0 +1,272 @@
+<script lang="ts">
+  import { MAX_ZOOM } from '$lib/actions/zoom-image';
+  import { assetViewerManager } from '$lib/managers/asset-viewer-manager.svelte';
+  import { getAssetUrls } from '$lib/utils';
+  import { scaleToFit, type ContentMetrics } from '$lib/utils/container-utils';
+  import type { AssetResponseDto, SharedLinkResponseDto } from '@immich/sdk';
+  import { TUNABLES } from '$lib/utils/tunables';
+  import { clamp } from 'lodash-es';
+  import { fade } from 'svelte/transition';
+
+  interface Props {
+    containerWidth: number;
+    containerHeight: number;
+    asset: AssetResponseDto;
+    sharedLink?: SharedLinkResponseDto;
+  }
+
+  let { containerWidth, containerHeight, asset, sharedLink }: Props = $props();
+
+  const MINIMAP_MAX = 192;
+  const MINIMAP_MIN = 100;
+  const minimapSize = $derived(clamp(Math.min(containerWidth, containerHeight) * 0.25, MINIMAP_MIN, MINIMAP_MAX));
+
+  const thumbnailUrl = $derived(getAssetUrls(asset, sharedLink).thumbnail);
+
+  const imageDimensions = $derived({
+    width: asset.width && asset.width > 0 ? asset.width : 1,
+    height: asset.height && asset.height > 0 ? asset.height : 1,
+  });
+
+  const container = $derived({ width: containerWidth, height: containerHeight });
+
+  // Scale the full container into the minimap square
+  const containerInMinimap = $derived(scaleToFit(container, { width: minimapSize, height: minimapSize }));
+  const minimapContainerScale = $derived(containerInMinimap.width / containerWidth);
+  const containerOffsetX = $derived((minimapSize - containerInMinimap.width) / 2);
+  const containerOffsetY = $derived((minimapSize - containerInMinimap.height) / 2);
+
+  // Position the image within the minimap's container representation
+  const imageInMinimap: ContentMetrics = $derived.by(() => {
+    const fitted = scaleToFit(imageDimensions, containerInMinimap);
+    return {
+      contentWidth: fitted.width,
+      contentHeight: fitted.height,
+      offsetX: containerOffsetX + (containerInMinimap.width - fitted.width) / 2,
+      offsetY: containerOffsetY + (containerInMinimap.height - fitted.height) / 2,
+    };
+  });
+
+  const { FADE_DURATION, HIDE_DELAY } = TUNABLES.MINIMAP;
+
+  let isDragging = $state(false);
+  let isDraggingZoom = $state(false);
+  let isRecentActivity = $state(false);
+  let hideTimer: ReturnType<typeof setTimeout> | null = null;
+
+  const resetHideTimer = () => {
+    isRecentActivity = true;
+    if (hideTimer !== null) {
+      clearTimeout(hideTimer);
+    }
+    hideTimer = setTimeout(() => {
+      isRecentActivity = false;
+      hideTimer = null;
+    }, HIDE_DELAY);
+  };
+
+  const isZoomed = $derived(assetViewerManager.zoom > 1);
+  const isVisible = $derived((isZoomed && isRecentActivity) || isDragging || isDraggingZoom);
+
+  $effect(() => {
+    // Track zoom state changes to reset the hide timer
+    const _state = assetViewerManager.zoomState;
+    void _state;
+    if (isZoomed) {
+      resetHideTimer();
+    }
+    return () => {
+      if (hideTimer !== null) {
+        clearTimeout(hideTimer);
+        hideTimer = null;
+      }
+    };
+  });
+
+  const zoomPercent = $derived(((assetViewerManager.zoom - 1) / (MAX_ZOOM - 1)) * 100);
+  const zoomLabel = $derived(assetViewerManager.zoom.toFixed(1) + 'x');
+
+  const clampPanPosition = (positionX: number, positionY: number, zoom: number) => ({
+    positionX: clamp(positionX, -(containerWidth * (zoom - 1)), 0),
+    positionY: clamp(positionY, -(containerHeight * (zoom - 1)), 0),
+  });
+
+  const minimapToContainerPosition = (minimapX: number, minimapY: number) => {
+    const containerX = (minimapX - containerOffsetX) / minimapContainerScale;
+    const containerY = (minimapY - containerOffsetY) / minimapContainerScale;
+    const { currentZoom } = assetViewerManager.zoomState;
+    const rawPositionX = containerWidth / 2 - containerX * currentZoom;
+    const rawPositionY = containerHeight / 2 - containerY * currentZoom;
+    return clampPanPosition(rawPositionX, rawPositionY, currentZoom);
+  };
+
+  const panToMinimapPosition = (event: PointerEvent) => {
+    const target = event.currentTarget as HTMLElement;
+    const rect = target.getBoundingClientRect();
+    const minimapX = event.clientX - rect.left;
+    const minimapY = event.clientY - rect.top;
+    const { positionX, positionY } = minimapToContainerPosition(minimapX, minimapY);
+    assetViewerManager.directTransform({ currentPositionX: positionX, currentPositionY: positionY });
+  };
+
+  const onPointerDown = (event: PointerEvent) => {
+    if (event.button !== 0) {
+      return;
+    }
+    isDragging = true;
+    assetViewerManager.setZoomEnabled(false);
+    (event.currentTarget as HTMLElement).setPointerCapture(event.pointerId);
+    panToMinimapPosition(event);
+    event.preventDefault();
+    event.stopPropagation();
+  };
+
+  const onPointerMove = (event: PointerEvent) => {
+    if (!isDragging) {
+      return;
+    }
+    panToMinimapPosition(event);
+  };
+
+  const onPointerUp = () => {
+    isDragging = false;
+    assetViewerManager.setZoomEnabled(true);
+  };
+
+  const zoomAroundCenter = (newZoom: number) => {
+    const { currentZoom, currentPositionX, currentPositionY } = assetViewerManager.zoomState;
+    const centerX = containerWidth / 2;
+    const centerY = containerHeight / 2;
+    const zoomTargetX = (centerX - currentPositionX) / currentZoom;
+    const zoomTargetY = (centerY - currentPositionY) / currentZoom;
+    const newPositionX = -zoomTargetX * newZoom + centerX;
+    const newPositionY = -zoomTargetY * newZoom + centerY;
+
+    assetViewerManager.directTransform({
+      currentZoom: newZoom,
+      currentPositionX: clamp(newPositionX, -(containerWidth * (newZoom - 1)), 0),
+      currentPositionY: clamp(newPositionY, -(containerHeight * (newZoom - 1)), 0),
+    });
+  };
+
+  const setZoomFromSlider = (event: PointerEvent) => {
+    const target = event.currentTarget as HTMLElement;
+    const rect = target.getBoundingClientRect();
+    const percent = clamp((event.clientX - rect.left) / rect.width, 0, 1);
+    zoomAroundCenter(1 + percent * (MAX_ZOOM - 1));
+  };
+
+  const WHEEL_ZOOM_RATIO = 0.1;
+
+  const onWheel = (event: WheelEvent) => {
+    event.preventDefault();
+    const { currentZoom } = assetViewerManager.zoomState;
+    const delta = -clamp(event.deltaY, -0.5, 0.5);
+    const newZoom = clamp(currentZoom + delta * WHEEL_ZOOM_RATIO * currentZoom, 1, MAX_ZOOM);
+    zoomAroundCenter(newZoom);
+  };
+
+  const onZoomSliderPointerDown = (event: PointerEvent) => {
+    if (event.button !== 0) {
+      return;
+    }
+    isDraggingZoom = true;
+    assetViewerManager.setZoomEnabled(false);
+    (event.currentTarget as HTMLElement).setPointerCapture(event.pointerId);
+    setZoomFromSlider(event);
+    event.preventDefault();
+    event.stopPropagation();
+  };
+
+  const onZoomSliderPointerMove = (event: PointerEvent) => {
+    if (!isDraggingZoom) {
+      return;
+    }
+    setZoomFromSlider(event);
+  };
+
+  const onZoomSliderPointerUp = () => {
+    isDraggingZoom = false;
+    assetViewerManager.setZoomEnabled(true);
+  };
+
+  const viewportRect = $derived.by(() => {
+    const { currentZoom, currentPositionX, currentPositionY } = assetViewerManager.zoomState;
+
+    // Visible area in container coordinates
+    const visibleLeft = -currentPositionX / currentZoom;
+    const visibleTop = -currentPositionY / currentZoom;
+    const visibleWidth = containerWidth / currentZoom;
+    const visibleHeight = containerHeight / currentZoom;
+
+    // Map to minimap coordinates
+    return {
+      left: visibleLeft * minimapContainerScale + containerOffsetX,
+      top: visibleTop * minimapContainerScale + containerOffsetY,
+      width: visibleWidth * minimapContainerScale,
+      height: visibleHeight * minimapContainerScale,
+    };
+  });
+</script>
+
+{#if isVisible}
+  <!-- svelte-ignore a11y_no_static_element_interactions -->
+  <div
+    class="absolute top-[68px] right-14 md:right-4 z-10 rounded-lg border border-white/30 bg-black/60 p-1 backdrop-blur-sm"
+    data-testid="zoom-minimap"
+    transition:fade={{ duration: FADE_DURATION }}
+  >
+    <!-- svelte-ignore a11y_no_static_element_interactions -->
+    <div
+      class="relative overflow-hidden rounded bg-black"
+      class:cursor-grabbing={isDragging}
+      class:cursor-pointer={!isDragging}
+      data-testid="zoom-minimap-canvas"
+      style="width: {minimapSize}px; height: {minimapSize}px;"
+      onpointerdown={onPointerDown}
+      onpointermove={onPointerMove}
+      onpointerup={onPointerUp}
+      onpointercancel={onPointerUp}
+      onwheel={onWheel}
+    >
+      <img
+        src={thumbnailUrl}
+        alt=""
+        class="absolute pointer-events-none"
+        draggable="false"
+        style="left: {imageInMinimap.offsetX}px; top: {imageInMinimap.offsetY}px; width: {imageInMinimap.contentWidth}px; height: {imageInMinimap.contentHeight}px;"
+      />
+      <div
+        class={[
+          'absolute border-2 border-white bg-white/20 pointer-events-none rounded-sm',
+          isDragging && 'border-white/80',
+        ]}
+        data-testid="zoom-minimap-viewport"
+        style="left: {viewportRect.left}px; top: {viewportRect.top}px; width: {viewportRect.width}px; height: {viewportRect.height}px;"
+      ></div>
+    </div>
+    <!-- svelte-ignore a11y_no_static_element_interactions -->
+    <div
+      class="relative mt-1 h-3 rounded-full bg-white/20 cursor-pointer"
+      class:cursor-grabbing={isDraggingZoom}
+      data-testid="zoom-minimap-slider"
+      style="width: {minimapSize}px;"
+      onpointerdown={onZoomSliderPointerDown}
+      onpointermove={onZoomSliderPointerMove}
+      onpointerup={onZoomSliderPointerUp}
+      onpointercancel={onZoomSliderPointerUp}
+    >
+      <div
+        class="absolute top-0 left-0 h-full rounded-full bg-white/80 pointer-events-none"
+        data-testid="zoom-minimap-slider-fill"
+        style="width: {zoomPercent}%;"
+      ></div>
+      <span
+        class="absolute inset-0 flex items-center justify-center text-[9px] font-semibold pointer-events-none select-none leading-none"
+        style="color: #000; text-shadow: 0 0 3px rgba(255,255,255,0.8);"
+      >
+        {zoomLabel}
+      </span>
+    </div>
+  </div>
+{/if}

web/src/lib/managers/asset-viewer-manager.svelte.ts

@@ -18,6 +18,8 @@ const createDefaultZoomState = (): ZoomImageWheelState => ({
 export type Events = {
   Zoom: [];
   ZoomChange: [ZoomImageWheelState];
+  DirectTransform: [ZoomImageWheelState];
+  ZoomEnabled: [boolean];
   Copy: [];
 };
 
@@ -87,6 +89,15 @@ export class AssetViewerManager extends BaseEventManager<Events> {
     this.#zoomState = state;
   }
 
+  directTransform(state: Partial<ZoomImageWheelState>) {
+    this.#zoomState = { ...this.#zoomState, ...state };
+    this.emit('DirectTransform', this.#zoomState);
+  }
+
+  setZoomEnabled(enabled: boolean) {
+    this.emit('ZoomEnabled', enabled);
+  }
+
   cancelZoomAnimation() {
     if (this.#animationFrameId !== null) {
       cancelAnimationFrame(this.#animationFrameId);

web/src/lib/utils/tunables.ts

@@ -31,4 +31,8 @@ export const TUNABLES = {
   IMAGE_THUMBNAIL: {
     THUMBHASH_FADE_DURATION: getNumber(storage.getItem('THUMBHASH_FADE_DURATION'), 100),
   },
+  MINIMAP: {
+    FADE_DURATION: getNumber(storage.getItem('MINIMAP.FADE_DURATION'), 150),
+    HIDE_DELAY: getNumber(storage.getItem('MINIMAP.HIDE_DELAY'), 1500),
+  },
 };