Switch to instead use SVG format for content body

src/components/messages/AudioWaveformView.vue

@@ -1,10 +1,9 @@
 <template>
-    <canvas ref="waveform">
-    </canvas>
+    <div v-html="content" class="waveform">
+    </div>
 </template>
 
 <script>
-//  import util from "../../plugins/utils";
 
 export default {
     props: {
@@ -15,65 +14,32 @@ export default {
             },
         },
     },
-    data() {
-        return {
-        };
-    },
-    mounted() {
-        this.drawWaveform(this.event);
-    },
-    methods: {
-        drawWaveform(event) {
-            const canvas = this.$refs.waveform;
-            if (canvas) {
-                const dpr = window.devicePixelRatio || 1;
-                canvas.width = canvas.offsetWidth * dpr;
-                canvas.height = (canvas.offsetHeight) * dpr;
-
-                const ctx = canvas.getContext("2d");
-
-                ctx.clearRect(0, 0, canvas.width, canvas.height);
-
-                const base64content = event ? event.getContent().formatted_body : undefined;
-                if (base64content) {
-                    const data = atob(base64content).split('').map(function (c) { return c.charCodeAt(0); });
-
-                    const drawLineSegment = (ctx, x, y0, data) => {
-                        ctx.lineWidth = 1; // how thick the line is
-                        ctx.strokeStyle = "#000"; // what color our line is
-                        ctx.beginPath();
-                        ctx.moveTo(x, y0 - data);
-                        ctx.lineTo(x, y0 + data);
-                        ctx.stroke();
-                    };
-
-                    console.log("W", canvas.width, canvas.height, canvas.offsetWidth, canvas.offsetHeight);
-
-                    const width = canvas.width;
-                    const height = canvas.height;
-                    const samples = data.length;
-                    for (let i = 0; i < width; i++) {
-                        if (i % 4 == 2 || i % 4 == 3) continue;
-                        const iSample = Math.floor(width == 0 ? 0 :(1000 * i) / width);
-                        const sample = iSample < samples ? data[iSample] : 0;
-                        drawLineSegment(ctx, i, height/2, (sample / 255) * height / 2);
+    computed: {
+        content() {
+            return this.$sanitize(
+                this.event ? this.event.getContent().formatted_body : "",
+                {
+                    allowedTags: ["svg", "path"],
+                    allowedAttributes: {
+                        'svg': ["viewbox", "fill", "preserveaspectratio", "xmlns"],
+                        'path': ["d", "style"]
                     }
                 }
-            }
-
+            );
         }
     },
-    watch: {
-        event: {
-            immediate: false,
-            handler(event) {
-                this.drawWaveform(event);
-            }
-        }
-    }
 };
 </script>
 
 <style lang="scss">
 @import "@/assets/css/chat.scss";
+
+.waveform svg {
+    width: 100%;
+    height: 100%;
+
+    path {
+        stroke: black !important;
+    }
+}
 </style>

src/plugins/utils.js

@@ -526,10 +526,19 @@ class Util {
                     // Integerize
                     filteredData = filteredData.map(n => parseInt((n * 255).toFixed()));
                     
-                    const base64 = Buffer.from(filteredData).toString('base64'); //.replace(/=/g, '')
-                    console.log("BASE64", base64);
+
+                    // Generate SVG of waveform
+                    let svg = `<svg viewBox="0 0 ${samples} 255" fill="none" preserveAspectRatio="none" xmlns="http://www.w3.org/2000/svg">`;
+                    svg += `<path d="`;
+                    filteredData.forEach((d, i) => {
+                        const delta = d / 2; 
+                        svg += `M${i} ${128 - delta}V${128 + delta}`;
+                    });
+                    svg += `" style="fill:none;stroke:green;stroke-width:1" />`;
+                    svg += "</svg>";
+
                     messageContent.format = "org.matrix.custom.html";
-                    messageContent.formatted_body = base64;
+                    messageContent.formatted_body = svg;
                 })
         }
     }