Merge pull request #195 from pacien/scroll-zoom

viewer/LdPicture: implement mousewheel and pinch zoom

4 files changed, 168 insertions, 33 deletions

diff --git a/viewer/src/@types/gallery.d.ts b/viewer/src/@types/gallery.d.ts
index de1c0dd..956ab6b 100644
--- a/viewer/src/@types/gallery.d.ts
+++ b/viewer/src/@types/gallery.d.ts
@@ -49,12 +49,17 @@ declare namespace Gallery {
         thumbnail?: Thumbnail
         properties: OtherProperties | PictureProperties | DirectoryProperties,
     }
+    interface Resolution {
+        width: number,
+        height: number,
+    }
     interface OtherProperties {
         type: "other",
     }
     interface PictureProperties {
         type: "picture",
         resource: string,
+        resolution: Resolution
     }
     interface DirectoryProperties {
         type: "directory",
@@ -62,10 +67,7 @@ declare namespace Gallery {
     }
     interface Thumbnail {
         resource: string,
-        resolution: {
-            width: number,
-            height: number,
-        }
+        resolution: Resolution
     }
     type RawTag = string;
     type ItemType = "other" | "picture" | "directory";
diff --git a/viewer/src/components/LdPicture.vue b/viewer/src/components/LdPicture.vue
index 3170c81..de46bcb 100644
--- a/viewer/src/components/LdPicture.vue
+++ b/viewer/src/components/LdPicture.vue
@@ -18,17 +18,21 @@
 -->
 
 <template>
+  <!-- FIXME: v-dragscroll interferes with pinch-to-zoom -->
   <div
+    ref="containerElement"
     v-dragscroll
-    class="scrollbar"
-    :class="{'fit-to-screen': !$uiStore.fullscreen, 'original-size': $uiStore.fullscreen}"
+    class="scrollbar ld-picture-container"
     @click.capture="e => dragScrollClickFix.onClickCapture(e)"
-    @click="$uiStore.toggleFullscreen()"
+    @dblclick="$uiStore.toggleFullscreen()"
+    @dragstart.prevent
     @dragscrollstart="dragScrollClickFix.onDragScrollStart()"
     @dragscrollend="dragScrollClickFix.onDragScrollEnd()"
   >
     <v-lazy-image
+      ref="imageElement"
       :src="pictureSrc(picture.properties.resource)"
+      class="ld-picture-element"
       :class="{'slow-loading': Boolean(slowLoadingStyle)}"
       :style="slowLoadingStyle"
       @load="clearSlowLoading"
@@ -38,12 +42,15 @@
 </template>
 
 <script lang="ts">
-import { Component, Vue, Prop } from "vue-property-decorator";
+import { Component, Vue, Prop, Ref } from "vue-property-decorator";
+import LdZoom from "@/services/ldzoom";
 import DragScrollClickFix from "@/services/dragscrollclickfix";
 
 @Component
 export default class LdPicture extends Vue {
   @Prop({ required: true }) readonly picture!: Gallery.Picture;
+  @Ref() readonly containerElement!: HTMLDivElement;
+  @Ref() readonly imageElement!: Vue;
 
   readonly SLOW_LOADING_TIMEOUT_MS: number = 1500;
   readonly dragScrollClickFix = new DragScrollClickFix();
@@ -54,6 +61,7 @@ export default class LdPicture extends Vue {
 
   mounted() {
     this.timer = setTimeout(this.generateSlowLoadingStyle, this.SLOW_LOADING_TIMEOUT_MS);
+    new LdZoom(this.containerElement, this.imageElement.$el as HTMLImageElement, this.picture.properties, 10, 1 / 5).install();
   }
 
   destroyed() {
@@ -85,13 +93,17 @@ export default class LdPicture extends Vue {
 <style lang="scss">
 @import "~@/assets/scss/theme.scss";
 
-.ld-picture-loader {
-  position: relative;
-  & .loading-background {
-    background: none !important;
-  }
+.ld-picture-container {
+  height: 100%;
 }
-img.slow-loading {
+
+.ld-picture-element {
+  max-width: unset;
+  max-height: unset;
+  cursor: grab;
+}
+
+.slow-loading {
   background-repeat: no-repeat;
   background-position: center;
   background-size: contain;
@@ -99,25 +111,11 @@ img.slow-loading {
   background-blend-mode: soft-light;
   opacity: 1 !important;
 }
-.fit-to-screen {
-  display: flex;
-  justify-content: space-around;
-  height: 100%;
-  & > img {
-    object-fit: contain;
-    cursor: zoom-in;
-  }
-}
-.original-size {
-  display: block;
-  text-align: center;
-  cursor: grab;
-  height: 100%;
-  & > img {
-    max-width: unset;
-    max-height: unset;
-    object-fit: none;
-    cursor: zoom-out;
+
+.ld-picture-loader {
+  position: relative;
+  & .loading-background {
+    background: none !important;
   }
 }
 </style>
diff --git a/viewer/src/services/ldzoom.ts b/viewer/src/services/ldzoom.ts
new file mode 100644
index 0000000..c28c2c8
--- /dev/null
+++ b/viewer/src/services/ldzoom.ts
@@ -0,0 +1,134 @@
+/* ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2020  Pacien TRAN-GIRARD
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+// polyfill still required for IE and Safari, see https://caniuse.com/#feat=resizeobserver
+import ResizeObserver from 'resize-observer-polyfill';
+import "hammerjs";
+
+/**
+ * Mousewheel and pinch zoom handler.
+ */
+export default class LdZoom {
+  readonly containerElement: HTMLDivElement;
+  readonly imageElement: HTMLImageElement;
+  readonly pictureProperties: Gallery.PictureProperties;
+  readonly maxScaleFactor: number;
+  readonly scrollZoomSpeed: number;
+  scaleFactor: number = 0.0;
+
+  constructor(
+    containerElement: HTMLDivElement, imageElement: HTMLImageElement,
+    pictureProperties: Gallery.PictureProperties,
+    maxScaleFactor: number, scrollZoomSpeed: number
+  ) {
+    this.containerElement = containerElement;
+    this.imageElement = imageElement;
+    this.pictureProperties = pictureProperties;
+    this.maxScaleFactor = maxScaleFactor;
+    this.scrollZoomSpeed = scrollZoomSpeed;
+  }
+
+  /**
+   * Register event listeners.
+   */
+  public install() {
+    this.updateImageScale(this.scaleFactor);
+
+    new ResizeObserver(() => {
+      this.updateImageScale(this.scaleFactor);
+    }).observe(this.containerElement);
+
+    this.containerElement.addEventListener('wheel', wheelEvent => {
+      wheelEvent.preventDefault();
+      const scaleFactor = this.scaleFactor - Math.sign(wheelEvent.deltaY) * this.scrollZoomSpeed;
+      this.zoom(wheelEvent.offsetX, wheelEvent.offsetY, scaleFactor);
+    });
+
+    const pinchListener = new Hammer(this.containerElement);
+    pinchListener.get('pinch').set({enable: true});