c# - 将 RGB 字节转换为 HSL 并返回？

Question

是否有一种算法可以将 RGB byte 数组转换为 HSL float 数组并再次转换回来？

我试过找到的 here但它似乎有错误。

Answer 1

我使用以下类将 HSL 转换为 RGB，反之亦然。您可以从 Color 构造一个 ColorRGB 实例，或者简单地转换一个。它还公开了 H、S、L 属性。我在网上找到的。向原作者致歉，我找不到引用:

  public class ColorRGB
  {
    public byte R;
    public byte G;
    public byte B;
    public byte A;

    public ColorRGB()
    {
      R = 255;
      G = 255;
      B = 255;
      A = 255;
    }

    public ColorRGB(Color value)
    {
      this.R = value.R;
      this.G = value.G;
      this.B = value.B;
      this.A = value.A;
    }
    public static implicit operator Color(ColorRGB rgb)
    {
      Color c = Color.FromArgb(rgb.A, rgb.R, rgb.G, rgb.B);
      return c;
    }
    public static explicit operator ColorRGB(Color c)
    {
      return new ColorRGB(c);
    }


    // Given H,S,L in range of 0-1
    // Returns a Color (RGB struct) in range of 0-255
    public static ColorRGB FromHSL(double H, double S, double L)
    {
      return FromHSLA(H, S, L, 1.0);
    }

    // Given H,S,L,A in range of 0-1
    // Returns a Color (RGB struct) in range of 0-255
    public static ColorRGB FromHSLA(double H, double S, double L, double A)
    {
      double v;
      double r, g, b;
      if (A > 1.0)
        A = 1.0;

      r = L;   // default to gray
      g = L;
      b = L;
      v = (L <= 0.5) ? (L * (1.0 + S)) : (L + S - L * S);
      if (v > 0)
      {
        double m;
        double sv;
        int sextant;
        double fract, vsf, mid1, mid2;

        m = L + L - v;
        sv = (v - m) / v;
        H *= 6.0;
        sextant = (int)H;
        fract = H - sextant;
        vsf = v * sv * fract;
        mid1 = m + vsf;
        mid2 = v - vsf;
        switch (sextant)
        {
          case 0:
            r = v;
            g = mid1;
            b = m;
            break;
          case 1:
            r = mid2;
            g = v;
            b = m;
            break;
          case 2:
            r = m;
            g = v;
            b = mid1;
            break;
          case 3:
            r = m;
            g = mid2;
            b = v;
            break;
          case 4:
            r = mid1;
            g = m;
            b = v;
            break;
          case 5:
            r = v;
            g = m;
            b = mid2;
            break;
        }
      }
      ColorRGB rgb = new ColorRGB();
      rgb.R = Convert.ToByte(r * 255.0f);
      rgb.G = Convert.ToByte(g * 255.0f);
      rgb.B = Convert.ToByte(b * 255.0f);
      rgb.A = Convert.ToByte(A * 255.0f);
      return rgb;
    }

    // Hue in range from 0.0 to 1.0
    public float H
    {
      get
      {
        // Use System.Drawing.Color.GetHue, but divide by 360.0F 
        // because System.Drawing.Color returns hue in degrees (0 - 360)
        // rather than a number between 0 and 1.
        return ((Color)this).GetHue() / 360.0F;
      }
    }

    // Saturation in range 0.0 - 1.0
    public float S
    {
      get
      {
        return ((Color)this).GetSaturation();
      }
    }

    // Lightness in range 0.0 - 1.0
    public float L
    {
      get
      {
        return ((Color)this).GetBrightness();
      }
    }
  }