keanu-weblite/src/components/messages/AudioWaveformView.vue

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2.4 KiB
Vue

<template>
<canvas ref="waveform">
</canvas>
</template>
<script>
// import util from "../../plugins/utils";
export default {
props: {
event: {
type: Object,
default: function () {
return null;
},
},
},
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);
}
}
}
}
},
watch: {
event: {
immediate: false,
handler(event) {
this.drawWaveform(event);
}
}
}
};
</script>
<style lang="scss">
@import "@/assets/css/chat.scss";
</style>