From 6ffb771eeb7b7c55f8c0fb1297939b9969c634d9 Mon Sep 17 00:00:00 2001
From: Stefan Dej <meteyou@gmail.com>
Date: Tue, 24 May 2022 10:06:03 +0200
Subject: [PATCH] fix: stop webcam when webcam panel is collapse (#839)

---
 src/components/webcams/Mjpegstreamer.vue      | 54 +++++++++++++++----
 .../webcams/MjpegstreamerAdaptive.vue         | 27 +++++++---
 src/components/webcams/Uv4lMjpeg.vue          | 40 +++++++++++---
 src/main.ts                                   |  4 +-
 4 files changed, 99 insertions(+), 26 deletions(-)

diff --git a/src/components/webcams/Mjpegstreamer.vue b/src/components/webcams/Mjpegstreamer.vue
index 741e4dc0..818f9e92 100644
--- a/src/components/webcams/Mjpegstreamer.vue
+++ b/src/components/webcams/Mjpegstreamer.vue
@@ -1,6 +1,7 @@
 <style>
 .webcamImage {
     width: 100%;
+    background: lightgray;
 }
 
 .webcamFpsOutput {
@@ -16,7 +17,12 @@
 
 <template>
     <div style="position: relative">
-        <img ref="image" class="webcamImage" :style="webcamStyle" />
+        <img
+            ref="image"
+            v-observe-visibility="visibilityChanged"
+            class="webcamImage"
+            :style="webcamStyle"
+            @load="onload" />
         <span v-if="showFps" class="webcamFpsOutput">{{ $t('Panels.WebcamPanel.FPS') }}: {{ fpsOutput }}</span>
     </div>
 </template>
@@ -32,6 +38,8 @@ const TYPE_JPEG = 'image/jpeg'
 @Component
 export default class Mjpegstreamer extends Mixins(BaseMixin) {
     private currentFPS = 0
+    private streamState = false
+    private aspectRatio: null | number = null
     private timerFPS: number | null = null
     private timerRestart: number | null = null
     private stream: ReadableStream | null = null
@@ -58,12 +66,19 @@ export default class Mjpegstreamer extends Mixins(BaseMixin) {
     }
 
     get webcamStyle() {
+        const output = {
+            transform: 'none',
+            aspectRatio: 16 / 9,
+        }
+
         let transforms = ''
         if ('flipX' in this.camSettings && this.camSettings.flipX) transforms += ' scaleX(-1)'
         if ('flipX' in this.camSettings && this.camSettings.flipY) transforms += ' scaleY(-1)'
-        if (transforms.trimLeft().length) return { transform: transforms.trimLeft() }
+        if (transforms.trimStart().length) output.transform = transforms.trimStart()
 
-        return ''
+        if (this.aspectRatio) output.aspectRatio = this.aspectRatio
+
+        return output
     }
 
     get fpsOutput() {
@@ -71,6 +86,8 @@ export default class Mjpegstreamer extends Mixins(BaseMixin) {
     }
 
     startStream() {
+        this.streamState = true
+
         const SOI = new Uint8Array(2)
         SOI[0] = 0xff
         SOI[1] = 0xd8
@@ -91,7 +108,7 @@ export default class Mjpegstreamer extends Mixins(BaseMixin) {
         const { signal } = this.controller
 
         //readable stream credit to from https://github.com/aruntj/mjpeg-readable-stream
-        fetch(this.url, { signal })
+        fetch(this.url, { signal, mode: 'cors' })
             .then((response) => response.body)
             .then((rb) => {
                 const reader = rb?.getReader()
@@ -116,10 +133,8 @@ export default class Mjpegstreamer extends Mixins(BaseMixin) {
 
                 this.stream = new ReadableStream({
                     start(controller) {
-                        return pump()
-
                         // The following function handles each data chunk
-                        function pump(): any {
+                        const pump = (): any => {
                             // "done" is a Boolean and value a "Uint8Array"
                             return reader?.read().then(({ done, value }) => {
                                 // If there is no more data to read
@@ -165,22 +180,25 @@ export default class Mjpegstreamer extends Mixins(BaseMixin) {
                                 return pump()
                             })
                         }
+
+                        return pump()
                     },
                 })
             })
     }
 
     mounted() {
-        document.addEventListener('visibilitychange', this.visibilityChanged)
+        document.addEventListener('visibilitychange', this.documentVisibilityChanged)
         this.startStream()
     }
 
     beforeDestroy() {
-        document.removeEventListener('visibilitychange', this.visibilityChanged)
+        document.removeEventListener('visibilitychange', this.documentVisibilityChanged)
         this.stopStream()
     }
 
     stopStream() {
+        this.streamState = false
         URL.revokeObjectURL(this.url)
         if (this.timerFPS) clearTimeout(this.timerFPS)
         if (this.timerRestart) clearTimeout(this.timerRestart)
@@ -195,18 +213,32 @@ export default class Mjpegstreamer extends Mixins(BaseMixin) {
 
     @Watch('url')
     urlChanged() {
+        this.aspectRatio = null
         this.restartStream()
     }
 
-    visibilityChanged() {
+    // this function check if you changed the browser tab
+    documentVisibilityChanged() {
         const visibility = document.visibilityState
+        this.visibilityChanged(visibility === 'visible')
+    }
 
-        if (visibility === 'visible') {
+    // this function is to stop the stream, on scroll or on collapse the webcam panel
+    visibilityChanged(newVal: boolean) {
+        if (newVal && this.streamState) return
+
+        if (newVal) {
             this.startStream()
             return
         }
 
         this.stopStream()
     }
+
+    onload() {
+        if (this.aspectRatio === null && this.$refs.image) {
+            this.aspectRatio = this.$refs.image.naturalWidth / this.$refs.image.naturalHeight
+        }
+    }
 }
 </script>
diff --git a/src/components/webcams/MjpegstreamerAdaptive.vue b/src/components/webcams/MjpegstreamerAdaptive.vue
index f796dc65..bd11fdad 100644
--- a/src/components/webcams/MjpegstreamerAdaptive.vue
+++ b/src/components/webcams/MjpegstreamerAdaptive.vue
@@ -17,6 +17,7 @@
         </div>
         <canvas
             ref="mjpegstreamerAdaptive"
+            v-observe-visibility="visibilityChanged"
             width="600"
             height="400"
             :style="webcamStyle"
@@ -46,6 +47,7 @@ export default class MjpegstreamerAdaptive extends Mixins(BaseMixin) {
     private time_smoothing = 0.6
     private request_time_smoothing = 0.1
     private currentFPS = 0
+    private aspectRatio: null | number = null
 
     declare $refs: {
         mjpegstreamerAdaptive: any
@@ -56,12 +58,19 @@ export default class MjpegstreamerAdaptive extends Mixins(BaseMixin) {
     @Prop({ default: true }) declare showFps: boolean
 
     get webcamStyle() {
+        const output = {
+            transform: 'none',
+            aspectRatio: 16 / 9,
+        }
+
         let transforms = ''
         if ('flipX' in this.camSettings && this.camSettings.flipX) transforms += ' scaleX(-1)'
         if ('flipX' in this.camSettings && this.camSettings.flipY) transforms += ' scaleY(-1)'
-        if (transforms.trimLeft().length) return { transform: transforms.trimLeft() }
+        if (transforms.trimStart().length) output.transform = transforms.trimStart()
 
-        return ''
+        if (this.aspectRatio) output.aspectRatio = this.aspectRatio
+
+        return output
     }
 
     get fpsOutput() {
@@ -112,6 +121,9 @@ export default class MjpegstreamerAdaptive extends Mixins(BaseMixin) {
 
             canvas.width = canvas.clientWidth
             canvas.height = canvas.clientWidth * (frame.height / frame.width)
+            if (this.aspectRatio === null) {
+                this.aspectRatio = frame.width / frame.height
+            }
 
             ctx?.drawImage(frame, 0, 0, frame.width, frame.height, 0, 0, canvas.width, canvas.height)
             this.isLoaded = true
@@ -132,18 +144,21 @@ export default class MjpegstreamerAdaptive extends Mixins(BaseMixin) {
     }
 
     mounted() {
-        document.addEventListener('visibilitychange', this.visibilityChanged)
+        document.addEventListener('visibilitychange', this.documentVisibilityChanged)
         this.refreshFrame()
     }
 
     beforeDestroy() {
-        document.removeEventListener('visibilitychange', this.visibilityChanged)
+        document.removeEventListener('visibilitychange', this.documentVisibilityChanged)
     }
 
-    visibilityChanged() {
+    documentVisibilityChanged() {
         const visibility = document.visibilityState
+        this.visibilityChanged(visibility === 'visible')
+    }
 
-        if (visibility === 'visible') {
+    visibilityChanged(newVal: boolean) {
+        if (newVal) {
             this.isVisible = true
             this.refreshFrame()
             return
diff --git a/src/components/webcams/Uv4lMjpeg.vue b/src/components/webcams/Uv4lMjpeg.vue
index aec1b30c..c8bf9ffc 100644
--- a/src/components/webcams/Uv4lMjpeg.vue
+++ b/src/components/webcams/Uv4lMjpeg.vue
@@ -1,11 +1,19 @@
 <style scoped>
 .webcamImage {
     width: 100%;
+    background: lightgray;
 }
 </style>
 
 <template>
-    <img ref="webcamUv4lMjpegImage" :src="url" :alt="camSettings.name" :style="webcamStyle" class="webcamImage" />
+    <img
+        ref="webcamUv4lMjpegImage"
+        v-observe-visibility="visibilityChanged"
+        :src="url"
+        :alt="camSettings.name"
+        :style="webcamStyle"
+        class="webcamImage"
+        @load="onload" />
 </template>
 
 <script lang="ts">
@@ -15,6 +23,7 @@ import { GuiWebcamStateWebcam } from '@/store/gui/webcams/types'
 
 @Component
 export default class Uv4lMjpeg extends Mixins(BaseMixin) {
+    private aspectRatio: null | number = null
     @Prop({ required: true }) declare readonly camSettings: GuiWebcamStateWebcam
     @Prop({ default: null }) declare readonly printerUrl: string | null
 
@@ -30,20 +39,27 @@ export default class Uv4lMjpeg extends Mixins(BaseMixin) {
     }
 
     get webcamStyle() {
+        const output = {
+            transform: 'none',
+            aspectRatio: 16 / 9,
+        }
+
         let transforms = ''
         if ('flipX' in this.camSettings && this.camSettings.flipX) transforms += ' scaleX(-1)'
         if ('flipX' in this.camSettings && this.camSettings.flipY) transforms += ' scaleY(-1)'
-        if (transforms.trimLeft().length) return { transform: transforms.trimLeft() }
+        if (transforms.trimStart().length) output.transform = transforms.trimStart()
 
-        return ''
+        if (this.aspectRatio) output.aspectRatio = this.aspectRatio
+
+        return output
     }
 
     mounted() {
-        document.addEventListener('visibilitychange', this.visibilityChanged)
+        document.addEventListener('visibilitychange', this.documentVisibilityChanged)
     }
 
     beforeDestroy() {
-        document.removeEventListener('visibilitychange', this.visibilityChanged)
+        document.removeEventListener('visibilitychange', this.documentVisibilityChanged)
         this.stopStream()
     }
 
@@ -58,15 +74,25 @@ export default class Uv4lMjpeg extends Mixins(BaseMixin) {
         }
     }
 
-    visibilityChanged() {
+    documentVisibilityChanged() {
         const visibility = document.visibilityState
+        this.visibilityChanged(visibility === 'visible')
+    }
 
-        if (visibility === 'visible') {
+    visibilityChanged(newVal: boolean) {
+        if (newVal) {
             this.startStream()
             return
         }
 
         this.stopStream()
     }
+
+    onload() {
+        if (this.aspectRatio === null && this.$refs.webcamUv4lMjpegImage) {
+            this.aspectRatio =
+                this.$refs.webcamUv4lMjpegImage.naturalWidth / this.$refs.webcamUv4lMjpegImage.naturalHeight
+        }
+    }
 }
 </script>
diff --git a/src/main.ts b/src/main.ts
index 20daf724..01ed9792 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -19,8 +19,8 @@ const updateSW = registerSW({
 Vue.config.productionTip = false
 
 // vue-observe-visibility
-import VueObserveVisibility from 'vue-observe-visibility'
-Vue.use(VueObserveVisibility)
+import { ObserveVisibility } from 'vue-observe-visibility'
+Vue.directive('observe-visibility', ObserveVisibility)
 
 //vue-meta
 import VueMeta from 'vue-meta'