From 9a2ebbabe2e9f0c292701d33f36f9b7a457b1164 Mon Sep 17 00:00:00 2001
From: Ramires Viana <59319979+ramiresviana@users.noreply.github.com>
Date: Tue, 14 Jul 2020 01:18:53 +0000
Subject: [PATCH] fix: blinking previewer

---
 .../src/components/files/ExtendedImage.vue    |  89 +++++++++---
 frontend/src/components/files/Preview.vue     | 132 ++++++++++--------
 frontend/src/store/index.js                   |   3 +-
 frontend/src/store/mutations.js               |   3 +
 frontend/src/views/Files.vue                  |   5 +-
 5 files changed, 153 insertions(+), 79 deletions(-)

diff --git a/frontend/src/components/files/ExtendedImage.vue b/frontend/src/components/files/ExtendedImage.vue
index 2fa0f35e..aeb27981 100644
--- a/frontend/src/components/files/ExtendedImage.vue
+++ b/frontend/src/components/files/ExtendedImage.vue
@@ -10,10 +10,12 @@
     @mouseup="mouseUp"
     @wheel="wheelMove"
   >
-    <img :src="src" class="image-ex-img" ref="imgex" @load="setCenter">
+    <img :src="src" class="image-ex-img image-ex-img-center" ref="imgex" @load="onLoad">
   </div>
 </template>
 <script>
+import throttle from 'lodash.throttle'
+
 export default {
   props: {
     src: String,
@@ -50,7 +52,12 @@ export default {
       inDrag: false,
       lastTouchDistance: 0,
       moveDisabled: false,
-      disabledTimer: null
+      disabledTimer: null,
+      imageLoaded: false,
+      position: {
+        center: { x: 0, y: 0 },
+        relative: { x: 0, y: 0 }
+      }
     }
   },
   mounted() {
@@ -63,24 +70,47 @@ export default {
     if (getComputedStyle(container).height === "0px") {
       container.style.height = "100%"
     }
+
+    window.addEventListener('resize', this.onResize)
+  },
+  beforeDestroy () {
+    window.removeEventListener('resize', this.onResize)
+    document.removeEventListener('mouseup', this.onMouseUp)
   },
   methods: {
+    onLoad() {
+      let img = this.$refs.imgex
+
+      this.imageLoaded = true
+
+      if (img === undefined) {
+        return
+      }
+
+      img.classList.remove('image-ex-img-center')
+      this.setCenter()
+      img.classList.add('image-ex-img-ready')
+
+      document.addEventListener('mouseup', this.onMouseUp)
+    },
+    onMouseUp() {
+      this.inDrag = false
+    },
+    onResize: throttle(function() {
+      if (this.imageLoaded) {
+        this.setCenter()
+        this.doMove(this.position.relative.x, this.position.relative.y)
+      }
+    }, 100),
     setCenter() {
       let container = this.$refs.container
       let img = this.$refs.imgex
 
-      let rate = Math.min(
-        container.clientWidth / img.clientWidth,
-        container.clientHeight / img.clientHeight
-      )
-      if (!this.autofill && rate > 1) {
-        rate = 1
-      }
-      // height will be auto set
-      img.width = Math.floor(img.clientWidth * rate)
-      img.style.top = `${Math.floor((container.clientHeight - img.clientHeight) / 2)}px`
-      img.style.left = `${Math.floor((container.clientWidth - img.clientWidth) / 2)}px`
-      document.addEventListener('mouseup', () => this.inDrag = false )
+      this.position.center.x = Math.floor((container.clientWidth - img.clientWidth) / 2)
+      this.position.center.y = Math.floor((container.clientHeight - img.clientHeight) / 2)
+
+      img.style.left = this.position.center.x + 'px'
+      img.style.top = this.position.center.y + 'px'
     },
     mousedownStart(event) {
       this.lastX = null
@@ -159,8 +189,22 @@ export default {
     },
     doMove(x, y) {
       let style = this.$refs.imgex.style
-      style.left = `${this.pxStringToNumber(style.left) + x}px`
-      style.top = `${this.pxStringToNumber(style.top) + y}px`
+      let posX = this.pxStringToNumber(style.left) + x
+      let posY = this.pxStringToNumber(style.top) + y
+
+      style.left = posX + 'px'
+      style.top = posY + 'px'
+
+      this.position.relative.x =  Math.abs(this.position.center.x - posX)
+      this.position.relative.y =  Math.abs(this.position.center.y - posY)
+
+      if (posX < this.position.center.x) {
+        this.position.relative.x = this.position.relative.x * -1
+      }
+
+      if (posY < this.position.center.y) {
+        this.position.relative.y = this.position.relative.y * -1
+      }
     },
     wheelMove(event) {
       this.scale += (event.wheelDeltaY / 100) * this.zoomStep
@@ -185,9 +229,20 @@ export default {
 }
 
 .image-ex-img {
+  position: absolute;
+}
+
+.image-ex-img-center {
+  left: 50%;
+  top: 50%;
+  transform: translate(-50%, -50%);
+  position: absolute;
+  transition: none;
+}
+
+.image-ex-img-ready {
   left: 0;
   top: 0;
-  position: absolute;
   transition: transform 0.1s ease;
 }
 </style>
diff --git a/frontend/src/components/files/Preview.vue b/frontend/src/components/files/Preview.vue
index f0a7ef02..b065d185 100644
--- a/frontend/src/components/files/Preview.vue
+++ b/frontend/src/components/files/Preview.vue
@@ -5,16 +5,14 @@
         <i class="material-icons">close</i>
       </button>
 
-      <template v-if="!loading">
-        <div class="title">
-          <span>{{ req.name }}</span>
-        </div>
+      <div class="title">
+        <span>{{ this.name }}</span>
+      </div>
 
-        <rename-button v-if="user.perm.rename"></rename-button>
-        <delete-button v-if="user.perm.delete"></delete-button>
-        <download-button v-if="user.perm.download"></download-button>
-        <info-button></info-button>
-      </template>
+      <rename-button :disabled="loading" v-if="user.perm.rename"></rename-button>
+      <delete-button :disabled="loading" v-if="user.perm.delete"></delete-button>
+      <download-button :disabled="loading" v-if="user.perm.download"></download-button>
+      <info-button :disabled="loading"></info-button>
     </div>
 
     <div class="loading" v-if="loading">
@@ -25,33 +23,34 @@
       </div>
     </div>
 
-    <template v-if="!loading">
-      <button class="action" @click="prev" v-show="hasPrevious" :aria-label="$t('buttons.previous')" :title="$t('buttons.previous')">
-        <i class="material-icons">chevron_left</i>
-      </button>
-      <button class="action" @click="next" v-show="hasNext" :aria-label="$t('buttons.next')" :title="$t('buttons.next')">
-        <i class="material-icons">chevron_right</i>
-      </button>
+    <button class="action" @click="prev" v-show="hasPrevious" :aria-label="$t('buttons.previous')" :title="$t('buttons.previous')">
+      <i class="material-icons">chevron_left</i>
+    </button>
+    <button class="action" @click="next" v-show="hasNext" :aria-label="$t('buttons.next')" :title="$t('buttons.next')">
+      <i class="material-icons">chevron_right</i>
+    </button>
 
-    <div class="preview">
-      <ExtendedImage v-if="req.type == 'image'" :src="raw"></ExtendedImage>
-      <audio v-else-if="req.type == 'audio'" :src="raw" autoplay controls></audio>
-      <video v-else-if="req.type == 'video'" :src="raw" autoplay controls>
-        <track
-          kind="captions"
-          v-for="(sub, index) in subtitles"
-          :key="index"
-          :src="sub"
-          :label="'Subtitle ' + index" :default="index === 0">
-        Sorry, your browser doesn't support embedded videos,
-        but don't worry, you can <a :href="download">download it</a>
-        and watch it with your favorite video player!
-      </video>
-      <object v-else-if="req.extension == '.pdf'" class="pdf" :data="raw"></object>
-      <a v-else-if="req.type == 'blob'" :href="download">
-        <h2 class="message">{{ $t('buttons.download') }} <i class="material-icons">file_download</i></h2>
-      </a>
-    </div>
+    <template v-if="!loading">
+      <div class="preview">
+        <ExtendedImage v-if="req.type == 'image'" :src="raw"></ExtendedImage>
+        <audio v-else-if="req.type == 'audio'" :src="raw" autoplay controls></audio>
+        <video v-else-if="req.type == 'video'" :src="raw" autoplay controls>
+          <track
+            kind="captions"
+            v-for="(sub, index) in subtitles"
+            :key="index"
+            :src="sub"
+            :label="'Subtitle ' + index" :default="index === 0">
+          Sorry, your browser doesn't support embedded videos,
+          but don't worry, you can <a :href="download">download it</a>
+          and watch it with your favorite video player!
+        </video>
+        <object v-else-if="req.extension == '.pdf'" class="pdf" :data="raw"></object>
+        <a v-else-if="req.type == 'blob'" :href="download">
+          <h2 class="message">{{ $t('buttons.download') }} <i class="material-icons">file_download</i></h2>
+        </a>
+      </div>
+    </template>
   </div>
 </template>
 
@@ -87,6 +86,7 @@ export default {
       previousLink: '',
       nextLink: '',
       listing: null,
+      name: '',
       subtitles: []
     }
   },
@@ -111,30 +111,24 @@ export default {
       return `${this.previewUrl}&inline=true`
     }
   },
+  watch: {
+    $route: function () {
+      this.updatePreview()
+    }
+  },
   async mounted () {
     window.addEventListener('keyup', this.key)
-
-    if (this.req.subtitles) {
-      this.subtitles = this.req.subtitles.map(sub => `${baseURL}/api/raw${sub}?auth=${this.jwt}&inline=true`)
-    }
-
-    try {
-      if (this.oldReq.items) {
-        this.updateLinks(this.oldReq.items)
-      } else {
-        const path = url.removeLastDir(this.$route.path)
-        const res = await api.fetch(path)
-        this.updateLinks(res.items)
-      }
-    } catch (e) {
-      this.$showError(e)
-    }
+    this.$store.commit('setPreviewMode', true)
+    this.listing = this.oldReq.items
+    this.updatePreview()
   },
   beforeDestroy () {
     window.removeEventListener('keyup', this.key)
+    this.$store.commit('setPreviewMode', false)
   },
   methods: {
     back () {
+      this.$store.commit('setPreviewMode', false)
       let uri = url.removeLastDir(this.$route.path) + '/'
       this.$router.push({ path: uri })
     },
@@ -153,22 +147,42 @@ export default {
         if (this.hasPrevious) this.prev()
       }
     },
-    updateLinks (items) {
-      for (let i = 0; i < items.length; i++) {
-        if (items[i].name !== this.req.name) {
+    async updatePreview () {
+      if (this.req.subtitles) {
+        this.subtitles = this.req.subtitles.map(sub => `${baseURL}/api/raw${sub}?auth=${this.jwt}&inline=true`)
+      }
+
+      let dirs = this.$route.fullPath.split("/")
+      this.name = decodeURIComponent(dirs[dirs.length - 1])
+
+      if (!this.listing) {
+        try {
+          const path = url.removeLastDir(this.$route.path)
+          const res = await api.fetch(path)
+          this.listing = res.items
+        } catch (e) {
+          this.$showError(e)
+        }
+      }
+
+      this.previousLink = ''
+      this.nextLink = ''
+
+      for (let i = 0; i < this.listing.length; i++) {
+        if (this.listing[i].name !== this.name) {
           continue
         }
 
         for (let j = i - 1; j >= 0; j--) {
-          if (mediaTypes.includes(items[j].type)) {
-            this.previousLink = items[j].url
+          if (mediaTypes.includes(this.listing[j].type)) {
+            this.previousLink = this.listing[j].url
             break
           }
         }
 
-        for (let j = i + 1; j < items.length; j++) {
-          if (mediaTypes.includes(items[j].type)) {
-            this.nextLink = items[j].url
+        for (let j = i + 1; j < this.listing.length; j++) {
+          if (mediaTypes.includes(this.listing[j].type)) {
+            this.nextLink = this.listing[j].url
             break
           }
         }
diff --git a/frontend/src/store/index.js b/frontend/src/store/index.js
index 3662d3a6..40b56df4 100644
--- a/frontend/src/store/index.js
+++ b/frontend/src/store/index.js
@@ -23,7 +23,8 @@ const state = {
   show: null,
   showShell: false,
   showMessage: null,
-  showConfirm: null
+  showConfirm: null,
+  previewMode: false
 }
 
 export default new Vuex.Store({
diff --git a/frontend/src/store/mutations.js b/frontend/src/store/mutations.js
index 579edbec..caefcf53 100644
--- a/frontend/src/store/mutations.js
+++ b/frontend/src/store/mutations.js
@@ -82,6 +82,9 @@ const mutations = {
   resetClipboard: (state) => {
     state.clipboard.key = ''
     state.clipboard.items = []
+  },
+  setPreviewMode(state, value) {
+    state.previewMode = value
   }
 }
 
diff --git a/frontend/src/views/Files.vue b/frontend/src/views/Files.vue
index af54a91c..c0e03bfc 100644
--- a/frontend/src/views/Files.vue
+++ b/frontend/src/views/Files.vue
@@ -10,14 +10,15 @@
         <router-link :to="link.url">{{ link.name }}</router-link>
       </span>
     </div>
+
     <div v-if="error">
       <not-found v-if="error.message === '404'"></not-found>
       <forbidden v-else-if="error.message === '403'"></forbidden>
       <internal-error v-else></internal-error>
     </div>
+    <preview v-else-if="isPreview"></preview>
     <editor v-else-if="isEditor"></editor>
     <listing :class="{ multiple }" v-else-if="isListing"></listing>
-    <preview v-else-if="isPreview"></preview>
     <div v-else>
       <h2 class="message">
         <span>{{ $t('files.loading') }}</span>
@@ -65,7 +66,7 @@ export default {
       'show'
     ]),
     isPreview () {
-      return !this.loading && !this.isListing && !this.isEditor
+      return !this.loading && !this.isListing && !this.isEditor || this.loading && this.$store.state.previewMode
     },
     breadcrumbs () {
       let parts = this.$route.path.split('/')