music/demos/visualizer.html

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<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  <meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1, user-scalable=yes">
  <link rel="stylesheet" href="./style.css">
  <title>Visualizer</title>
  <style>
    input[type="file"] {
      width: 0;
      height: 0;
      opacity: 0;
      cursor: pointer;
      display: none;
    }

    textarea {
      display: block;
      margin-bottom: 4px;
    }
  </style>

  <style id="customStyle">
  </style>
</head>
<body>
  <h1>Visualizers</h1>
  <p>
    There are several MIDI or <code>NoteSequence</code> visualizers available.
    You can connect it to an <code>mm.Player</code> to update the visualization
    in sync with the audio.
  </p>

  <section>
    <p>Load a melody in any of these formats:</p>
    <button id="urlBtn">Load URL</button>
    <button id="seqBtn">Load NoteSequence</button>
    <label class="button">
      Load midi file
      <input type="file" id="fileInput">
    </label>
    <br><br>
    <button id="playBtn" disabled>wait...</button>
    <span class="input">
      <b>Tempo:</b>
      <input id="tempoInput" value="100" type="range" min="20" max="240" value="120" step="1">
      <span id="tempoValue"></span>
    </span>
  </section>

  <h2 id="PianoRollSVGVisualizer">mm.PianoRollSVGVisualizer</h2>
  <section>
    <div class="visualizer-container">
      <svg id="svg"></svg>
    </div>
  </section>

  <h2>mm.StaffSVGVisualizer</h2>
  <section>
    <div class="visualizer-container">
      <div id="staff"></div>
    </div>
  </section>

  <h2>mm.WaterfallSVGVisualizer</h2>
  <section>
    <label><input type="checkbox" id="waterfallCheckbox">Show only necessary octaves</label>
    <br>
    <div class="visualizer-container">
      <div id="waterfall">
      </div>
    </div>
  </section>

  <h2>mm.PianoRollCanvasVisualizer</h2>
  <section>
    <p>
      <b>Note:</b> This has the same visual output as <code>mm.PianoRollSVGVisualizer</code>,
      but using a canvas instead of an svg. This visualizers also redraws the entire
      sequence on every time step. For longer sequences, canvases become really expensive and
      big, and might crash the renderer.
      We recommend using the <code>PianoRollSVGVisualizer</code>mm.PianoRollSVGVisualizer</code>,
      if performance is a concern.
    </p>
    <div class="visualizer-container">
      <canvas id="canvas"></canvas>
    </div>
  </section>

  <h2>Styling SVG visualizers</h2>
  <section>
    <p>
      SVG visualizers (piano roll and waterfall) support CSS! Use a selector like
      <code>svg rect.note</code> to match notes, and style them using the
      <a href="https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/Presentation">
        available CSS properties</a>. More advanced styling is possible:
      <ul>
        <li>Currently playing notes can be matched using the <code>.active</code> class.</li>
        <li>Notes can also be matched based on properties like instrument or pitch (using
            <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors">
              attribute selectors</a>), thanks to the
            data attributes <code>data-instrument</code>, <code>data-program</code>,
            <code>data-is-drum</code> and <code>data-pitch</code>.</li>
        <li>A <code>--midi-velocity</code> custom property is defined on every note and can be
            accessed using the
            <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/var">
              <code>var()</code> CSS function</a>.</li>
      </ul>
    </p>
    <p>
      To demonstrate this, we need a slightly juiced up version of our <code>NoteSequence</code>:
      <button id="seqVelBtn">Load</button>
    </p>
    <p>Click below to apply the following style sheet:
    <textarea id="styleInput" rows="10" cols="100">
svg rect.note {
  fill: rgb(calc(var(--midi-velocity) * 1.2 + 100), 30, calc(255 - var(--midi-velocity)));
}

svg rect.note.active {
  stroke: black;
  stroke-width: 1.5;
  stroke-opacity: 0.5;
}</textarea>
    <button id="applyStyleBtn">Apply</button></p>
  </section>

  <script src="visualizer_bundle.js"></script>
</body>
</html>