Add better camera access for non-cordova deployments (#116)

This adds direct javascript access to the camera (with permission requests). Capturing an image with the camera now happens right on the detect page and not a separate window.

This also opens the possibility of live detection on the web app.

Reviewed-on: Georgi_Lab/ALVINN_f7#116

src/pages/detect.vue

@@ -7,7 +7,11 @@
     <f7-block class="detect-grid">
       <div class="image-container">
         <canvas id="im-draw" ref="image_cvs" @click="structureClick" :style="`display: ${imageLoaded ? 'block' : 'none'}; flex: 1 1 0%; max-width: 100%; max-height: 100%; min-width: 0; min-height: 0; background-size: contain; background-position: center; background-repeat: no-repeat`" />
-        <SvgIcon v-if="!imageView" :icon="f7route.params.region" fill-color="var(--avn-theme-color)" @click="selectImage" />
+        <SvgIcon v-if="!imageView && !videoAvailable" :icon="f7route.params.region" fill-color="var(--avn-theme-color)" @click="selectImage" />
+        <div class="vid-container" v-if="videoAvailable" style="width: 100%; height: 100%">
+          <video id="vid-view" ref="vid_viewer" :srcObject="cameraStream" :autoPlay="true" style="width: 100%; height: 100%"></video>
+          <f7-button @click="captureVidFrame()" style="position: absolute; bottom: 32px; left: 50%; transform: translateX(-50%);" fill>Capture</f7-button>
+        </div>
       </div>
       <div v-if="(resultData && resultData.detections) || detecting" class="chip-results" style="grid-area: result-view; flex: 0 0 auto; align-self: center;">
         <f7-chip v-for="result in showResults.filter( r => { return r.aboveThreshold && r.isSearched && !r.isDeleted })"
@@ -47,7 +51,7 @@
           <SvgIcon :icon="(uploadUid) ? 'cloud_done' : 'cloud_upload'"/>
         </f7-button>
       </f7-segmented>
-      <input type="file" ref="image_chooser" @change="getImage()" accept="image/*" capture="environment" style="display: none;"/>
+      <input type="file" ref="image_chooser" @change="getImage()" accept="image/*" style="display: none;"/>
     </f7-block>
 
     <f7-panel :id="detectorName + '-settings'" right cover :backdrop="false" :container-el="`#${detectorName}-detect-page`">
@@ -86,7 +90,7 @@
         <f7-button style="height: auto; width: auto;" popover-close="#capture-popover" @click="selectImage('file')">
           <SvgIcon icon="photo_library" />
         </f7-button>
-        <f7-button style="height: auto; width: auto;" popover-close="#capture-popover" class="disabled" @click="videoStream">
+        <f7-button style="height: auto; width: auto;" popover-close="#capture-popover" @click="videoStream">
           <SvgIcon icon="videocam"/>
         </f7-button>
       </f7-segmented>
@@ -321,7 +325,10 @@
         uploadUid: null,
         uploadDirty: false,
         modelLocation: '',
-        modelLoading: false
+        modelLoading: false,
+        videoDeviceAvailable: false,
+        videoAvailable: false,
+        cameraStream: null
       }
     },
     setup() {
@@ -480,18 +487,36 @@
           this.detectorLabels.forEach( s => s.detect = false )
         }
       },
-      selectImage (mode) {
+      async selectImage (mode) {
         this.imageLoadMode = mode
-        if (mode == "camera") {
-          this.$refs.image_chooser.setAttribute("capture","environment")
-        } else {
-          this.$refs.image_chooser.removeAttribute("capture")
-        }
         if (this.isCordova && mode == "camera") {
             navigator.camera.getPicture(this.getImage, this.onFail, { quality: 50, destinationType: Camera.DestinationType.DATA_URL, correctOrientation: true });
-        } else {
-          var loadResult = this.$refs.image_chooser.click()
+            return
         }
+        if (mode == "camera") {
+          const devicesList = await navigator.mediaDevices.enumerateDevices()
+          this.videoDeviceAvailable = devicesList.some( d => d.kind == "videoinput")
+          if (this.videoDeviceAvailable) {
+            navigator.mediaDevices.getUserMedia({video: true})
+            var vidConstraint = {
+              video: {
+                width: {
+                  ideal: 1920
+                },
+                height: {
+                  ideal: 1080
+                },
+                facingMode: 'environment'
+              },
+              audio: false
+            }
+            const stream = await navigator.mediaDevices.getUserMedia(vidConstraint);
+            this.videoAvailable = true
+            this.cameraStream = stream
+            return
+          }
+        }
+        var loadResult = this.$refs.image_chooser.click()
       },
       onFail (message) {
         alert(`Camera fail: ${message}`)
@@ -539,7 +564,11 @@
       },
       getImage (searchImage) {
         let loadImage = new Promise(resolve => {
-          if (this.isCordova && this.imageLoadMode == "camera") {
+          if (this.videoAvailable) {
+            this.cameraStream.getTracks().forEach( t => t.stop())
+            this.videoAvailable = false
+            resolve(searchImage)
+          } else if (this.isCordova && this.imageLoadMode == "camera") {
             resolve('data:image/jpg;base64,' + searchImage)
           } else {
             const searchImage = this.$refs.image_chooser.files[0]
@@ -573,9 +602,18 @@
           f7.dialog.alert(`Error loading image: ${e.message}`)
         })
       },
-      videoStream() {
+      async videoStream() {
         //TODO
-        return null
+      },
+      captureVidFrame() {
+        const vidViewer = this.$refs.vid_viewer
+        vidViewer.pause()
+        let tempCVS = document.createElement('canvas')
+        tempCVS.height = vidViewer.videoHeight || parseInt(vidViewer.style.height)
+        tempCVS.width = vidViewer.videoWidth || parseInt(vidViewer.style.width)
+        const tempCtx = tempCVS.getContext('2d')
+        tempCtx.drawImage(vidViewer, 0, 0)
+        this.getImage(tempCVS.toDataURL())
       },
       async submitData () {
         var uploadData = this.showResults