.NET Framework 3.5是否有HsbToRgb转换器,还是需要自己编写？

Question

我在文档中搜索了一个HsbToRgb转换器,但没有发现任何包含"hsb"或"hsl"的内容,所以我猜它只是不存在.但是,确保是否有支持此转换的类？

更新

我最终选择了这个,这与0xA3略有不同.我还添加了一个,AhsbToArgb所以我可以转换为RGB并一次设置alpha通道.

AhsbToArgb - 允许alpha通道:

public static Color AhsbToArgb(byte a, double h, double s, double b)
{
    var color = HsbToRgb(h, s, b);
    return Color.FromArgb(a, color.R, color.G, color.B);
}

HsbToRgb - 将色调饱和度 - 亮度转换为红 - 绿 - 蓝色:

public static Color HsbToRgb(double h, double s, double b)
{
    if (s == 0)
        return RawRgbToRgb(b, b, b);
    else
    {
        var sector = h / 60;
        var sectorNumber = (int)Math.Truncate(sector);
        var sectorFraction = sector - sectorNumber;
        var b1 = b * (1 - s);
        var b2 = b * (1 - s * sectorFraction);
        var b3 = b * (1 - s * (1 - sectorFraction));
        switch (sectorNumber)
        {
            case 0:
                return RawRgbToRgb(b, b3, b1);
            case 1:
                return RawRgbToRgb(b2, b, b1);
            case 2:
                return RawRgbToRgb(b1, b, b3);
            case 3:
                return RawRgbToRgb(b1, b2, b);
            case 4:
                return RawRgbToRgb(b3, b1, b);
            case 5:
                return RawRgbToRgb(b, b1, b2);
            default:
                throw new ArgumentException("Hue must be between 0 and 360");
        }
    }
}

RawRgbToRgb - 将双精度转换为整数并返回颜色对象:

private static Color RawRgbToRgb(double rawR, double rawG, double rawB)
{
    return Color.FromArgb(
        (int)Math.Round(rawR * 255),
        (int)Math.Round(rawG * 255),
        (int)Math.Round(rawB * 255));
}

Answer 1

不,据我所知,不是.但算法并不是很复杂,您可以在Web上找到工作代码,例如Guillaume Leparmentier 在.NET上操作颜色的 CodeProject文章中的代码:

public static Color HSBtoRGB(double hue, double saturation, double brightness)
{
    double r = 0;
    double g = 0;
    double b = 0;

    if (saturation == 0)
    {
        r = g = b = brightness;
    }
    else
    {
        // The color wheel consists of 6 sectors. 
        // Figure out which sector you're in.
        //
        double sectorPos = hue / 60.0;
        int sectorNumber = (int)(Math.Floor(sectorPos));

        // get the fractional part of the sector
        double fractionalSector = sectorPos - sectorNumber;

        // calculate values for the three axes of the color. 
        double p = brightness * (1.0 - saturation);
        double q = brightness * (1.0 - (saturation * fractionalSector));
        double t = brightness * (1.0 - (saturation * (1 - fractionalSector)));

        // assign the fractional colors to r, g, and b 
        // based on the sector the angle is in.
        switch (sectorNumber)
        {
            case 0:
                r = brightness;
                g = t;
                b = p;
                break;
            case 1:
                r = q;
                g = brightness;
                b = p;
                break;
            case 2:
                r = p;
                g = brightness;
                b = t;
                break;
            case 3:
                r = p;
                g = q;
                b = brightness;
                break;
            case 4:
                r = t;
                g = p;
                b = brightness;
                break;
            case 5:
                r = brightness;
                g = p;
                b = q;
                break;
        }
    }

    return Color.FromArgb(
        (int)(r * 255.0 + 0.5), 
        (int)(g * 255.0 + 0.5), 
        (int)(b * 255.0 + 0.5));
}

Answer 2

不,在.NET中(直至并包括4.0)的Color类只自动地从RGB转换为HSB(通过GetHue,GetSaturation和GetBrightness方法).您必须使用自己的方法从HSB值转换为RGB值,或使用已编写的示例,如:

http://www.codeproject.com/KB/GDI-plus/HSBColorClass.aspx