如何在Asp.net中使用HSL [关闭]

Question

在.net中使用哪些工具处理HSL颜色？

Answer 1

color结构提供了三种方法：GetHue，GetSaturation和GetBrightness。

鲍勃鲍威尔几年前写了一篇有趣的文章 。

奇怪的历史记录 - “HSL”（以及相关的“HSV”）是源于施乐公司70年代的Palo Alto研究中心（PARC）的众多事物之一，由Alvy Ray Smith提供 。

Answer 2

此ColorRGB类提供了获取和设置HSL的方法，以及与System.Drawing.Color之间的隐式转换。 它基于GeekMonkey.com的一个很好的例子。

using System;
using System.Drawing;

namespace RMA.Drawing
{
  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();
      }
    }
  }
}

Answer 3

除了secretGeek的答案，要从HSL值中获取颜色（反之亦然），您还可以使用这些本机函数调用（Visual Basic中的示例代码）：

Public Declare Sub ColorRGBToHLS Lib "shlwapi.dll" _
                                    (ByVal clrRGB As UInteger, _
                                     ByRef pwHue As Short, _
                                     ByRef pwLuminance As Short, _
                                     ByRef pwSaturation As Short)
Public Declare Function ColorHLSToRGB Lib "shlwapi.dll" _
                                        (ByVal wHue As Short, _
                                         ByVal wLuminance As Short, _
                                         ByVal wSaturation As Short) As UInteger

（在传递/接收颜色参数/结果时使用ColorTranslator.ToWin32和ColorTranslator.FromWin32 ）