1 files changed, 100 insertions, 0 deletions
diff --git a/animism-align/frontend/app/views/editor/timeline/components/waveform.component.js b/animism-align/frontend/app/views/editor/timeline/components/waveform.component.js
new file mode 100644
index 0000000..0161129
--- /dev/null
+++ b/animism-align/frontend/app/views/editor/timeline/components/waveform.component.js
@@ -0,0 +1,100 @@
+import React, { Component } from 'react'
+// import { Link } from 'react-router-dom'
+import { connect } from 'react-redux'
+
+import actions from 'app/actions'
+
+import {
+  WAVEFORM_SIZE, INNER_HEIGHT,
+  ZOOM_STEPS, ZOOM_LABEL_STEPS, ZOOM_TICK_STEPS,
+} from 'app/constants'
+
+class Waveform extends Component {
+  constructor(props){
+    super(props)
+    this.canvasRef = React.createRef()
+  }
+  componentDidMount() {
+    this.resize()
+    this.draw()
+  }
+  componentDidUpdate() {
+    this.draw()
+  }
+  resize() {
+    const canvas = this.canvasRef.current
+    canvas.width = WAVEFORM_SIZE
+    canvas.height = INNER_HEIGHT
+  }
+  draw() {
+    const canvas = this.canvasRef.current
+    const ctx = canvas.getContext('2d')
+    const h = INNER_HEIGHT
+    this.clearCanvas(ctx, h)
+    this.drawCurve(ctx, h)
+  }
+  clearCanvas(ctx, h) {  
+    const w = WAVEFORM_SIZE
+    ctx.clearRect(0, 0, w, h)
+    ctx.fillStyle = 'rgba(0,0,0,0.5)'
+    ctx.fillRect(0, 0, w, h)
+    ctx.fillStyle = 'rgba(64,128,192,0.5)'
+  }
+  drawCurve(ctx, h) {
+    let { peaks, timeline } = this.props
+    let { start_ts, zoom, duration } = timeline
+
+    let secondsPerPixel = ZOOM_STEPS[zoom] * 0.1 // 0.1 sec / step
+    let stepsPerPixel = ZOOM_STEPS[zoom] // 0.1 sec / step
+
+    let widthTimeDuration = h * secondsPerPixel // secs per pixel
+
+    let timeMin = Math.round(start_ts / secondsPerPixel) * secondsPerPixel
+    let timeMax = Math.min(timeMin + widthTimeDuration, duration)
+    let timeWidth = timeMax - timeMin
+
+    let stepMin = Math.floor(timeMin * 10)
+    let pixelWidth = Math.ceil(timeWidth / secondsPerPixel)
+
+    let i = 0
+    let step = stepMin
+    let waveformPeak = WAVEFORM_SIZE / 2
+    let origin = (1 - peaks[step]) * waveformPeak
+    let y
+    let peak
+    // console.log(stepMin, pixelWidth * stepsPerPixel + stepMin)
+    ctx.beginPath()
+    ctx.moveTo(origin, 0)
+    for (i = 0; i < pixelWidth; i++) {
+      step = i * stepsPerPixel + stepMin
+      peak = peaks[step]
+      y = (1 - peak) * waveformPeak
+      ctx.lineTo(y, i)
+    }
+    for (i = pixelWidth - 1; i > 0; i--) {
+      step = i * stepsPerPixel + stepMin
+      peak = peaks[step]
+      y = (1 + peak) * waveformPeak
+      ctx.lineTo(y, i)
+    }
+    ctx.lineTo(origin, 0)
+    ctx.fillStyle = 'rgba(255,255,255,0.8)'
+    ctx.fill()
+  }
+  render() {
+    return (
+      <canvas
+        ref={this.canvasRef}
+        onMouseDown={this.props.onMouseDown}
+        onMouseUp={this.props.onMouseUp}
+      />
+    )
+  }
+}
+
+const mapStateToProps = state => ({
+  timeline: state.align.timeline,
+  peaks: state.align.peaks,
+})
+
+export default connect(mapStateToProps)(Waveform)