在c#中替换图像中的颜色

Question

在不影响纹理的情况下,C#替换图像某些部分的颜色的方式是什么？

你可以在这里看到结果的好例子
谢谢

Answer 1

有效替换颜色的一种方法是使用重映射表.在以下示例中,将在图片框内绘制图像.在Paint事件中,Color.Black的颜色更改为Color.Blue:

private void pictureBox_Paint(object sender, PaintEventArgs e)
{
    Graphics g = e.Graphics;
    using (Bitmap bmp = new Bitmap("myImage.png"))
    {

        // Set the image attribute's color mappings
        ColorMap[] colorMap = new ColorMap[1];
        colorMap[0] = new ColorMap();
        colorMap[0].OldColor = Color.Black;
        colorMap[0].NewColor = Color.Blue;
        ImageAttributes attr = new ImageAttributes();
        attr.SetRemapTable(colorMap);
        // Draw using the color map
        Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
        g.DrawImage(bmp, rect, 0, 0, rect.Width, rect.Height, GraphicsUnit.Pixel, attr);
    }
}

更多信息:http://msdn.microsoft.com/en-us/library/4b4dc1kz%28v=vs.110%29.aspx

Answer 2

在进行研究后，我发现没有有效/平滑的方法来做到这一点，所以我自己不这样做，代码可以被清理很多，但它可以完成工作，它效率不高但更流畅，并允许您设置容差。

public static Image ColorReplace(this Image inputImage, int tolerance, Color oldColor, Color NewColor)
    {
        Bitmap outputImage = new Bitmap(inputImage.Width, inputImage.Height);
        Graphics G = Graphics.FromImage(outputImage);
        G.DrawImage(inputImage, 0, 0);
        for (Int32 y = 0; y < outputImage.Height; y++)
            for (Int32 x = 0; x < outputImage.Width; x++)
            {
                Color PixelColor = outputImage.GetPixel(x, y);
                if (PixelColor.R > oldColor.R - tolerance && PixelColor.R < oldColor.R + tolerance && PixelColor.G > oldColor.G - tolerance && PixelColor.G < oldColor.G + tolerance && PixelColor.B > oldColor.B - tolerance && PixelColor.B < oldColor.B + tolerance)
                {
                    int RColorDiff = oldColor.R - PixelColor.R;
                    int GColorDiff = oldColor.G - PixelColor.G;
                    int BColorDiff = oldColor.B - PixelColor.B;

                    if (PixelColor.R > oldColor.R) RColorDiff = NewColor.R + RColorDiff;
                    else RColorDiff = NewColor.R - RColorDiff;
                    if (RColorDiff > 255) RColorDiff = 255;
                    if (RColorDiff < 0) RColorDiff = 0;
                    if (PixelColor.G > oldColor.G) GColorDiff = NewColor.G + GColorDiff;
                    else GColorDiff = NewColor.G - GColorDiff;
                    if (GColorDiff > 255) GColorDiff = 255;
                    if (GColorDiff < 0) GColorDiff = 0;
                    if (PixelColor.B > oldColor.B) BColorDiff = NewColor.B + BColorDiff;
                    else BColorDiff = NewColor.B - BColorDiff;
                    if (BColorDiff > 255) BColorDiff = 255;
                    if (BColorDiff < 0) BColorDiff = 0;

                    outputImage.SetPixel(x, y, Color.FromArgb(RColorDiff, GColorDiff, BColorDiff));
                }
            }
        return outputImage;
    }

Answer 3

尝试这个：

Color color = Color.Black; //Your desired colour

byte r = color.R; //For Red colour

Bitmap bmp = new Bitmap(this.BackgroundImage);
for (int x = 0; x < bmp.Width; x++)
{
    for (int y = 0; y < bmp.Height; y++)
    {
        Color gotColor = bmp.GetPixel(x, y);
        gotColor = Color.FromArgb(r, gotColor.G, gotColor.B);
        bmp.SetPixel(x, y, gotColor);
    }
}

Answer 4

找到了做到这一点的方法。这需要 RGB<->HSL 转换（我使用Rich Newman 的此类来实现 HSLColor：

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;

namespace ColorDemo
{
   public class HSLColor
   {
       // Private data members below are on scale 0-1
       // They are scaled for use externally based on scale
       private double hue = 1.0;
       private double saturation = 1.0;
       private double luminosity = 1.0;

       private const double scale = 240.0;

       public double Hue
       {
           get { return hue * scale; }
           set { hue = CheckRange(value / scale); }
       }
       public double Saturation
       {
           get { return saturation * scale; }
           set { saturation = CheckRange(value / scale); }
       }
       public double Luminosity
       {
           get { return luminosity * scale; }
           set { luminosity = CheckRange(value / scale); }
       }

       private double CheckRange(double value)
       {
           if (value < 0.0)
               value = 0.0;
           else if (value > 1.0)
               value = 1.0;
           return value;
       }

       public override string ToString()
       {
           return String.Format("H: {0:#0.##} S: {1:#0.##} L: {2:#0.##}", Hue, Saturation, Luminosity);
       }

       public string ToRGBString()
       {
           Color color = (Color)this;
           return String.Format("R: {0:#0.##} G: {1:#0.##} B: {2:#0.##}", color.R, color.G, color.B);
       }

       #region Casts to/from System.Drawing.Color
       public static implicit operator Color(HSLColor hslColor)
       {
           double r = 0, g = 0, b = 0;
           if (hslColor.luminosity != 0)
           {
               if (hslColor.saturation == 0)
                   r = g = b = hslColor.luminosity;
               else
               {
                   double temp2 = GetTemp2(hslColor);
                   double temp1 = 2.0 * hslColor.luminosity - temp2;

                   r = GetColorComponent(temp1, temp2, hslColor.hue + 1.0 / 3.0);
                   g = GetColorComponent(temp1, temp2, hslColor.hue);
                   b = GetColorComponent(temp1, temp2, hslColor.hue - 1.0 / 3.0);
               }
           }
           return Color.FromArgb((int)(255 * r), (int)(255 * g), (int)(255 * b));
       }

       private static double GetColorComponent(double temp1, double temp2, double temp3)
       {
           temp3 = MoveIntoRange(temp3);
           if (temp3 < 1.0 / 6.0)
               return temp1 + (temp2 - temp1) * 6.0 * temp3;
           else if (temp3 < 0.5)
               return temp2;
           else if (temp3 < 2.0 / 3.0)
               return temp1 + ((temp2 - temp1) * ((2.0 / 3.0) - temp3) * 6.0);
           else
               return temp1;
       }
       private static double MoveIntoRange(double temp3)
       {
           if (temp3 < 0.0)
               temp3 += 1.0;
           else if (temp3 > 1.0)
               temp3 -= 1.0;
           return temp3;
       }
       private static double GetTemp2(HSLColor hslColor)
       {
           double temp2;
           if (hslColor.luminosity < 0.5)  //<=??
               temp2 = hslColor.luminosity * (1.0 + hslColor.saturation);
           else
               temp2 = hslColor.luminosity + hslColor.saturation - (hslColor.luminosity * hslColor.saturation);
           return temp2;
       }

       public static implicit operator HSLColor(Color color)
       {
           HSLColor hslColor = new HSLColor();
           hslColor.hue = color.GetHue() / 360.0; // we store hue as 0-1 as opposed to 0-360 
           hslColor.luminosity = color.GetBrightness();
           hslColor.saturation = color.GetSaturation();
           return hslColor;
       }
       #endregion

       public void SetRGB(int red, int green, int blue)
       {
           HSLColor hslColor = (HSLColor)Color.FromArgb(red, green, blue);
           this.hue = hslColor.hue;
           this.saturation = hslColor.saturation;
           this.luminosity = hslColor.luminosity;
       }

       public HSLColor() { }
       public HSLColor(Color color)
       {
           SetRGB(color.R, color.G, color.B);
       }
       public HSLColor(int red, int green, int blue)
       {
           SetRGB(red, green, blue);
       }
       public HSLColor(double hue, double saturation, double luminosity)
       {
           this.Hue = hue;
           this.Saturation = saturation;
           this.Luminosity = luminosity;
       }

   }
}

1. 获取代表要替换的颜色的参考值（以 hsl 为单位）
2. 获取目标颜色的 hsl 值
3. 获取图像像素并对每个像素：
4. 计算像素的hsl值，并将其替换为(pixelHsl / refHsl) * targetHsl