Making Color From Alpha, Hue, Saturation and Brightness

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I find myself wanting to do this sometimes, so here’s a bit of code (I’m sure I stole this code from somewhere else);

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public static Color ColorFromAhsb(int a, float h, float s, float b) {

  if (0 > a || 255 < a) {
      throw new ArgumentOutOfRangeException(&quot;a&quot;);
  }
  if (0f > h || 360f < h) {
      throw new ArgumentOutOfRangeException(&quot;h&quot;);
  }
  if (0f > s || 1f < s) {
      throw new ArgumentOutOfRangeException(&quot;s&quot;);
  }
  if (0f > b || 1f < b) {
      throw new ArgumentOutOfRangeException(&quot;b&quot;);
  }

  if (0 == s) {
      return Color.FromArgb(a, Convert.ToInt32(b * 255),
          Convert.ToInt32(b * 255), Convert.ToInt32(b * 255));
  }

  float fMax, fMid, fMin;
  int iSextant, iMax, iMid, iMin;

  if (0.5 < b) {
      fMax = b - (b * s) + s;
      fMin = b + (b * s) - s;
  } else {
      fMax = b + (b * s);
      fMin = b - (b * s);
  }

  iSextant = (int)Math.Floor(h / 60f);
  if (300f <= h) {
      h -= 360f;
  }
  h /= 60f;
  h -= 2f * (float)Math.Floor(((iSextant + 1f) % 6f) / 2f);
  if (0 == iSextant % 2) {
      fMid = h * (fMax - fMin) + fMin;
  } else {
      fMid = fMin - h * (fMax - fMin);
  }

  iMax = Convert.ToInt32(fMax * 255);
  iMid = Convert.ToInt32(fMid * 255);
  iMin = Convert.ToInt32(fMin * 255);

  switch (iSextant) {
      case 1:
          return Color.FromArgb(a, iMid, iMax, iMin);
      case 2:
          return Color.FromArgb(a, iMin, iMax, iMid);
      case 3:
          return Color.FromArgb(a, iMin, iMid, iMax);
      case 4:
          return Color.FromArgb(a, iMid, iMin, iMax);
      case 5:
          return Color.FromArgb(a, iMax, iMin, iMid);
      default:
          return Color.FromArgb(a, iMax, iMid, iMin);
  }
}

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