From d2b5d28a17f3fc3ebfab1d2171e9bf67a87bd060 Mon Sep 17 00:00:00 2001
From: DavevanIersel <82802252+DavevanIersel@users.noreply.github.com>
Date: Fri, 8 Aug 2025 19:57:07 +0200
Subject: [PATCH] Added vertical continuous scroll

Added a setting for the epub viewer to continuously scroll vertically, and a setting which allows setting the viewing width of the page (works for paginated too)
---
 client/components/readers/EpubReader.vue | 87 ++++++++++++++++--------
 client/components/readers/Reader.vue     | 30 +++++++-
 client/strings/en-us.json                |  4 ++
 3 files changed, 91 insertions(+), 30 deletions(-)

diff --git a/client/components/readers/EpubReader.vue b/client/components/readers/EpubReader.vue
index a4c51539f..4100b01fe 100644
--- a/client/components/readers/EpubReader.vue
+++ b/client/components/readers/EpubReader.vue
@@ -1,13 +1,15 @@
 <template>
   <div id="epub-reader" class="h-full w-full">
     <div class="h-full flex items-center justify-center">
-      <button type="button" aria-label="Previous page" class="w-24 max-w-24 h-full hidden sm:flex items-center overflow-x-hidden justify-center opacity-50 hover:opacity-100">
+      <button v-if="ereaderSettings.flow === 'paginated'" type="button" aria-label="Previous page" class="w-24 max-w-24 h-full hidden sm:flex items-center overflow-x-hidden justify-center opacity-50 hover:opacity-100">
         <span v-if="hasPrev" class="material-symbols text-6xl" @mousedown.prevent @click="prev">chevron_left</span>
       </button>
-      <div id="frame" class="w-full" style="height: 80%">
-        <div id="viewer"></div>
+
+      <div id="frame" class="w-full" :class="isScrolled() ? 'absolute bottom-0 h-[90%]' : 'h-[80%]'">
+        <div id="viewer" class="flex justify-center" :class="{ 'h-full': isScrolled() }"></div>
       </div>
-      <button type="button" aria-label="Next page" class="w-24 max-w-24 h-full hidden sm:flex items-center justify-center overflow-x-hidden opacity-50 hover:opacity-100">
+
+      <button v-if="ereaderSettings.flow === 'paginated'" type="button" aria-label="Next page" class="w-24 max-w-24 h-full hidden sm:flex items-center justify-center overflow-x-hidden opacity-50 hover:opacity-100">
         <span v-if="hasNext" class="material-symbols text-6xl" @mousedown.prevent @click="next">chevron_right</span>
       </button>
     </div>
@@ -47,7 +49,9 @@ export default {
         fontScale: 100,
         lineSpacing: 115,
         spread: 'auto',
-        textStroke: 0
+        textStroke: 0,
+        flow: 'paginated',
+        widthPercentage: 100
       }
     }
   },
@@ -85,12 +89,12 @@ export default {
       return `ebookLocations-${this.libraryItemId}`
     },
     readerWidth() {
-      if (this.windowWidth < 640) return this.windowWidth
-      return this.windowWidth - 200
+      let width = Math.floor((this.windowWidth * this.ereaderSettings.widthPercentage) / 100)
+
+      return this.windowWidth < 640 || this.isScrolled() ? width : width - 200
     },
     readerHeight() {
-      if (this.windowHeight < 400 || !this.playerOpen) return this.windowHeight
-      return this.windowHeight - 164
+      return this.windowHeight < 400 || !this.playerOpen ? this.windowHeight : this.windowHeight - 164
     },
     ebookUrl() {
       if (this.fileId) {
@@ -103,21 +107,13 @@ export default {
       const isDark = theme === 'dark'
       const isSepia = theme === 'sepia'
 
-      const fontColor = isDark
-        ? '#fff'
-        : isSepia
-        ? '#5b4636'
-        : '#000'
+      const fontColor = isDark ? '#fff' : isSepia ? '#5b4636' : '#000'
 
-      const backgroundColor = isDark
-        ? 'rgb(35 35 35)'
-        : isSepia
-        ? 'rgb(244, 236, 216)'
-        : 'rgb(255, 255, 255)'
+      const backgroundColor = isDark ? 'rgb(35 35 35)' : isSepia ? 'rgb(244, 236, 216)' : 'rgb(255, 255, 255)'
 
       const lineSpacing = this.ereaderSettings.lineSpacing / 100
-      const fontScale   = this.ereaderSettings.fontScale   / 100
-      const textStroke  = this.ereaderSettings.textStroke  / 100
+      const fontScale = this.ereaderSettings.fontScale / 100
+      const textStroke = this.ereaderSettings.textStroke / 100
 
       return {
         '*': {
@@ -144,6 +140,11 @@ export default {
       this.rendition.themes.fontSize(`${fontScale}%`)
       this.rendition.themes.font(settings.font)
       this.rendition.spread(settings.spread || 'auto')
+      this.rendition.flow(settings.flow || 'paginated')
+      this.resize()
+    },
+    isScrolled() {
+      return this.ereaderSettings.flow === 'scrolled-continuous'
     },
     prev() {
       if (!this.rendition?.manager) return
@@ -312,6 +313,31 @@ export default {
         })
       }
     },
+    /**
+     * Adds a bottom spacer div to the last page's iframe content to allow extra scroll space.
+     * @param {object} view - The view object containing the iframe.
+     * @param {object} section - The current section object with an index.
+     */
+    addBottomSpacerToLastPage(view, section) {
+      const isLastPage = section.index === this.book?.spine?.spineItems?.length - 1
+      const doc = view?.iframe?.contentDocument || view?.iframe?.contentWindow?.document
+
+      if (!isLastPage || !doc) return
+
+      const existingSpacer = doc.getElementById('bottom-spacer')
+
+      if (!this.isScrolled()) {
+        existingSpacer?.remove()
+        return
+      }
+
+      if (existingSpacer) return
+
+      const newSpacer = doc.createElement('div')
+      newSpacer.id = 'bottom-spacer'
+      newSpacer.style.height = Math.floor(window.innerHeight / 2) + 'px'
+      doc.body.appendChild(newSpacer)
+    },
     initEpub() {
       /** @type {EpubReader} */
       const reader = this
@@ -338,20 +364,17 @@ export default {
 
       /** @type {ePub.Rendition} */
       reader.rendition = reader.book.renderTo('viewer', {
-        width: this.readerWidth,
-        height: this.readerHeight * 0.8,
         allowScriptedContent: this.allowScriptedContent,
-        spread: 'auto',
         snap: true,
-        manager: 'continuous',
-        flow: 'paginated'
+        manager: 'continuous'
       })
 
       // load saved progress
       reader.rendition.display(this.savedEbookLocation || reader.book.locations.start)
 
-      reader.rendition.on('rendered', () => {
+      reader.rendition.on('rendered', (section, view) => {
         this.applyTheme()
+        this.addBottomSpacerToLastPage(view, section)
       })
 
       reader.book.ready
@@ -453,7 +476,8 @@ export default {
     resize() {
       this.windowWidth = window.innerWidth
       this.windowHeight = window.innerHeight
-      this.rendition?.resize(this.readerWidth, this.readerHeight * 0.8)
+
+      this.rendition.resize(this.readerWidth, this.readerHeight * (this.isScrolled() ? 0.9 : 0.8))
     },
     applyTheme() {
       if (!this.rendition) return
@@ -474,3 +498,10 @@ export default {
   }
 }
 </script>
+<style>
+.epub-container {
+  /* Fixes unexpected scroll jump issue with epubjs continuous scroll: see https://github.com/futurepress/epub.js/issues/1303 */
+  overflow-anchor: none !important;
+  scrollbar-width: none;
+}
+</style>
diff --git a/client/components/readers/Reader.vue b/client/components/readers/Reader.vue
index 9063479d1..8ae92af52 100644
--- a/client/components/readers/Reader.vue
+++ b/client/components/readers/Reader.vue
@@ -109,11 +109,23 @@
           </div>
           <ui-range-input v-model="ereaderSettings.textStroke" :min="0" :max="300" :step="5" @input="settingsUpdated" />
         </div>
+        <div class="flex items-center mb-4">
+          <div class="w-40">
+            <p class="text-lg">{{ $strings.LabelPageWidth }}:</p>
+          </div>
+          <ui-range-input v-model="ereaderSettings.widthPercentage" :min="10" :max="100" :step="5" @input="settingsUpdated" />
+        </div>
+        <div class="flex items-center mb-4">
+          <div class="w-40">
+            <p class="text-lg">{{ $strings.LabelPageFlow }}:</p>
+          </div>
+          <ui-toggle-btns v-model="ereaderSettings.flow" :items="flowItems" @input="settingsUpdated" />
+        </div>
         <div class="flex items-center">
           <div class="w-40">
             <p class="text-lg">{{ $strings.LabelLayout }}:</p>
           </div>
-          <ui-toggle-btns v-model="ereaderSettings.spread" :items="spreadItems" @input="settingsUpdated" />
+          <ui-toggle-btns :disabled="ereaderSettings.flow === 'scrolled-continuous'" v-model="ereaderSettings.spread" :items="spreadItems" @input="settingsUpdated" />
         </div>
       </div>
     </modals-modal>
@@ -143,7 +155,9 @@ export default {
         lineSpacing: 115,
         fontBoldness: 100,
         spread: 'auto',
-        textStroke: 0
+        textStroke: 0,
+        flow: 'paginated',
+        widthPercentage: 100
       }
     }
   },
@@ -179,6 +193,18 @@ export default {
         }
       ]
     },
+    flowItems() {
+      return [
+        {
+          text: this.$strings.LabelFlowPaginated,
+          value: 'paginated'
+        },
+        {
+          text: this.$strings.LabelFlowScrolled,
+          value: 'scrolled-continuous'
+        }
+      ]
+    },
     themeItems() {
       return {
         theme: [
diff --git a/client/strings/en-us.json b/client/strings/en-us.json
index 70ac874d2..d0d8b77e1 100644
--- a/client/strings/en-us.json
+++ b/client/strings/en-us.json
@@ -376,6 +376,8 @@
   "LabelFilterByUser": "Filter by User",
   "LabelFindEpisodes": "Find Episodes",
   "LabelFinished": "Finished",
+  "LabelFlowPaginated": "Paginated",
+  "LabelFlowScrolled": "Scrolled",
   "LabelFolder": "Folder",
   "LabelFolders": "Folders",
   "LabelFontBold": "Bold",
@@ -495,6 +497,8 @@
   "LabelOpenIDGroupClaimDescription": "Name of the OpenID claim that contains a list of the user's groups. Commonly referred to as <code>groups</code>. <b>If configured</b>, the application will automatically assign roles based on the user's group memberships, provided that these groups are named case-insensitively 'admin', 'user', or 'guest' in the claim. The claim should contain a list, and if a user belongs to multiple groups, the application will assign the role corresponding to the highest level of access. If no group matches, access will be denied.",
   "LabelOpenRSSFeed": "Open RSS Feed",
   "LabelOverwrite": "Overwrite",
+  "LabelPageFlow": "Flow",
+  "LabelPageWidth": "Page Width",
   "LabelPaginationPageXOfY": "Page {0} of {1}",
   "LabelPassword": "Password",
   "LabelPath": "Path",