Bangle.js: fills the display with a color stripe

Bangle_ColorStripe.js

// fills the display of a Bangle.js with a color stripe

  Bangle.setLCDMode();                                // use normal display mode
  g.clear();

/**** HSVtoRGB ****/
// see https://en.wikipedia.org/wiki/HSL_and_HSV#HSV_to_RGB

  function HSVtoRGB (h, s, v) {
    let c = v*s;
    let k = h/60;
    let x = c*(1 - Math.abs(k%2 - 1));

    let r, g, b;
    switch (true) {
      case (k >=0) && (k <= 1): r = c; g = x; b = 0; break;
      case (k > 1) && (k <= 2): r = x; g = c; b = 0; break;
      case (k > 2) && (k <= 3): r = 0; g = c; b = x; break;
      case (k > 3) && (k <= 4): r = 0; g = x; b = c; break;
      case (k > 4) && (k <= 5): r = x; g = 0; b = c; break;
      case (k > 5) && (k <= 6): r = c; g = 0; b = x; break;
    }
    let m = v-c;

    return [
      Math.round(255*(r+m)), Math.round(255*(g+m)), Math.round(255*(b+m))
    ];
  }

/**** draw color stripe ****/

  const Width  = g.getWidth();
  const Height = g.getHeight();

  const Saturation = 1.0;
  const Value      = 1.0;

  for (let x = 0; x < Width; x++) {
    let Hue = Math.round(360*x/Width);
    let RGB = HSVtoRGB(Hue, Saturation, Value);
    g.setColor(RGB[0]/255,RGB[1]/255,RGB[2]/255);
    g.drawLine(x,0, x,Height-1);
  }