fix(web): Improve zoom behavior in photo-viewer. (immich-app#18803)

* Fix an issue where clicking the zoom-button after having zoomed in
would not zoom completely out, but leave the image in the zoomed-in
state. The new behavior properly zoomes the image completely out after
clicking the zoom-button.
* Revert to the default setting for `wheelZoomRatio` as the previous
setting of 0.2 was borderline unusable on a trackpad. This could
probably be moved to a user setting if needed.
* Add a keyboard shortcut 'z' to toggle image zoom.

Author: dagstuan

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

@@ -1,26 +1,20 @@
-import { photoZoomState, zoomed } from '$lib/stores/zoom-image.store';
+import { photoZoomState } from '$lib/stores/zoom-image.store';
 import { useZoomImageWheel } from '@zoom-image/svelte';
 import { get } from 'svelte/store';
 
-export { zoomed } from '$lib/stores/zoom-image.store';
-
 export const zoomImageAction = (node: HTMLElement) => {
   const { createZoomImage, zoomImageState, setZoomImageState } = useZoomImageWheel();
 
   createZoomImage(node, {
     maxZoom: 10,
-    wheelZoomRatio: 0.2,
   });
 
   const state = get(photoZoomState);
   if (state) {
     setZoomImageState(state);
   }
 
-  const unsubscribes = [
-    zoomed.subscribe((state) => setZoomImageState({ currentZoom: state ? 2 : 1 })),
-    zoomImageState.subscribe((state) => photoZoomState.set(state)),
-  ];
+  const unsubscribes = [photoZoomState.subscribe(setZoomImageState), zoomImageState.subscribe(photoZoomState.set)];
   return {
     destroy() {
       for (const unsubscribe of unsubscribes) {

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

@@ -1,8 +1,9 @@
 <script lang="ts">
   import { shortcuts } from '$lib/actions/shortcut';
-  import { zoomImageAction, zoomed } from '$lib/actions/zoom-image';
+  import { zoomImageAction } from '$lib/actions/zoom-image';
   import FaceEditor from '$lib/components/asset-viewer/face-editor/face-editor.svelte';
   import BrokenAsset from '$lib/components/assets/broken-asset.svelte';
+  import { castManager } from '$lib/managers/cast-manager.svelte';
   import { photoViewerImgElement, type TimelineAsset } from '$lib/stores/assets-store.svelte';
   import { isFaceEditMode } from '$lib/stores/face-edit.svelte';
   import { boundingBoxesArray } from '$lib/stores/people.store';
@@ -23,7 +24,6 @@
   import { fade } from 'svelte/transition';
   import LoadingSpinner from '../shared-components/loading-spinner.svelte';
   import { NotificationType, notificationController } from '../shared-components/notification/notification';
-  import { castManager } from '$lib/managers/cast-manager.svelte';
 
   interface Props {
     asset: AssetResponseDto;
@@ -65,7 +65,6 @@
     currentPositionX: 0,
     currentPositionY: 0,
   });
-  $zoomed = false;
 
   onDestroy(() => {
     $boundingBoxesArray = [];
@@ -108,7 +107,10 @@
   };
 
   zoomToggle = () => {
-    $zoomed = $zoomed ? false : true;
+    photoZoomState.set({
+      ...$photoZoomState,
+      currentZoom: $photoZoomState.currentZoom > 1 ? 1 : 2,
+    });
   };
 
   $effect(() => {
@@ -206,6 +208,7 @@
   use:shortcuts={[
     { shortcut: { key: 'c', ctrl: true }, onShortcut: onCopyShortcut, preventDefault: false },
     { shortcut: { key: 'c', meta: true }, onShortcut: onCopyShortcut, preventDefault: false },
+    { shortcut: { key: 'z' }, onShortcut: zoomToggle, preventDefault: false },
   ]}
 />
 {#if imageError}

web/src/lib/stores/zoom-image.store.ts

@@ -2,4 +2,3 @@ import type { ZoomImageWheelState } from '@zoom-image/core';
 import { writable } from 'svelte/store';
 
 export const photoZoomState = writable<ZoomImageWheelState>();
-export const zoomed = writable<boolean>();