C#中的图像色调修改

Question

我有一个图像,我想将该特定图像的色调修改为特定值.我知道rgb到hsl和hsl到rgb的转换数学公式但是我无法将这个东西实现到c#中.

以下是伪:

for(x=0;x<image_width;x++)
{
  for(y=0;y<image_height;y++)
  {
    Color oldColor=GetColorFromPixel(x,y);
    Color newColor=ModifyHue(oldColor);
    SetColorPixel(x,y,newColor);    
  }
}

谢谢

Answer 1

由于这个事实,Color结构已经有了GetHue(),GetSaturation()并且GetBrightness()从这些值构造颜色也会很好.所以我不久前在网上的某个地方找到了以下代码(目前无法再找到它,但它来自一个微软的家伙博客,他也有一个测试,逐步完成所有KnownColor).

/// <summary>
/// Creates a Color from alpha, hue, saturation and brightness.
/// </summary>
/// <param name="alpha">The alpha channel value.</param>
/// <param name="hue">The hue value.</param>
/// <param name="saturation">The saturation value.</param>
/// <param name="brightness">The brightness value.</param>
/// <returns>A Color with the given values.</returns>
public static Color FromAhsb(int alpha, float hue, float saturation, float brightness)
{

    if (0 > alpha || 255 < alpha)
    {
        throw new ArgumentOutOfRangeException("alpha", alpha,
          "Value must be within a range of 0 - 255.");
    }
    if (0f > hue || 360f < hue)
    {
        throw new ArgumentOutOfRangeException("hue", hue,
          "Value must be within a range of 0 - 360.");
    }
    if (0f > saturation || 1f < saturation)
    {
        throw new ArgumentOutOfRangeException("saturation", saturation,
          "Value must be within a range of 0 - 1.");
    }
    if (0f > brightness || 1f < brightness)
    {
        throw new ArgumentOutOfRangeException("brightness", brightness,
          "Value must be within a range of 0 - 1.");
    }

    if (0 == saturation)
    {
        return Color.FromArgb(alpha, Convert.ToInt32(brightness * 255),
          Convert.ToInt32(brightness * 255), Convert.ToInt32(brightness * 255));
    }

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

    if (0.5 < brightness)
    {
        fMax = brightness - (brightness * saturation) + saturation;
        fMin = brightness + (brightness * saturation) - saturation;
    }
    else
    {
        fMax = brightness + (brightness * saturation);
        fMin = brightness - (brightness * saturation);
    }

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

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

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

有了这个功能,你可以在HSB(或HSV)彩色演示文稿中的工作不是在HSL演示文稿中.有关它们之间差异的更多信息,请查看此维基百科文章.