C# 实现颜色的梯度渐变案例

为了表示不同的浓度值，对颜色条应用颜色梯度变化，基本方法是对ARGB分量乘以一个渐变系数。

下面是对十种颜色应用的三个梯度值的过程。

public void DrawRect(gasConcentration[] data)
   {
     Graphics graphic = pictureBox1.CreateGraphics();
     Graphics graphic2 = pictureBox2.CreateGraphics();
     int iCall2 = pictureBox2.Width/10;

data = new gasConcentration[40];
     int iLen = pictureBox1.Width = 540;
     int iHigh = pictureBox1.Height;
     //初始化十种颜色
     Color[] color = new Color[10] { Color.FromArgb(240, 0, 0), Color.Green, Color.Yellow, Color.Blue, Color.SteelBlue, Color.SeaGreen,
                   Color.Chartreuse, Color.SaddleBrown, Color.Violet, Color.BurlyWood};

//十个颜色，每个颜色三个深度
     for (int i = 0; i < 40; i++)
     {        
       data[i].gasType = i/4 + 1;
       data[i].gasConc = i％4;
     }
     Color c3, c4;
     if (data.Length > 0)
     {      
       int iCall = iLen / data.Length;
       pictureBox2.Width = iCall * data.Length;
       pictureBox1.Width = iCall * data.Length;
       iCall2 = iCall * 4;
       //画对比框条
       for (int i = 0; i < 10; i++)
       {          
         Brush brush1 = new LinearGradientBrush(new Point(0, iHigh), new Point(iCall2, iHigh), color[i], color[i]);
         graphic2.FillRectangle(brush1, 0 + iCall2 * i, 0, iCall2, iHigh);
         brush1.Dispose();
       }
       //画颜色条梯度分量
       for (int i = 0; i < data.Length; i++)
       {          
         //将颜色分为三个深度
         if (data[i].gasConc != 0)
           c3 = c4 = Color.FromArgb((byte)(255 * (float)(1 - (data[i].gasConc * 0.01))),
           (byte)(color[data[i].gasType-1].R * (float)(1 - (data[i].gasConc * 0.2))),
           (byte)(color[data[i].gasType-1].G * (float)(1 - (data[i].gasConc * 0.2))),
           (byte)(color[data[i].gasType-1].B * (float)(1 - (data[i].gasConc * 0.2))));
         else
           c3 = c4 = Color.Black;
         Brush brush1 = new LinearGradientBrush(new Point(0, iHigh), new Point(iCall, iHigh), c3, c4);
         graphic.FillRectangle(brush1, 0 + iCall * i , 0, iCall, iHigh);
         brush1.Dispose();                  
       }
     }
     else
     {
       c4 = color[0];
       Brush brush1 = new LinearGradientBrush(new Point(0, iHigh), new Point(iLen, iHigh), c4, c4);        
       graphic.FillRectangle(brush1, 0, 0, iLen, iHigh);
       brush1.Dispose();
     }

}

public struct gasConcentration
   {
     int iGasType;//气体名称
     int iGasConc;//气体浓度 // 0=no, 1=low, 2=med, 3=high

public int gasType { get { return iGasType; }
       set { iGasType = value; }    }
     public int gasConc { get { return iGasConc; }
       set { iGasConc = value; }
     }
   }

补充：C# 简单的颜色渐变算法

今天要用到一个颜色渐变的算法，网上看了很多，觉得都太繁琐，索性自己写一个。话不多说，直接上代码！

**这是用来获取某一颜色段的分度集合**
/// <summary>
   /// 获得某一颜色区间的颜色集合
   /// </summary>
   /// <param name="sourceColor">起始颜色</param>
   /// <param name="destColor">终止颜色</param>
   /// <param name="count">分度数</param>
   /// <returns>返回颜色集合</returns>
   public static List<Color> GetSingleColorList(Color srcColor, Color desColor, int count)
   {
     List<Color> colorFactorList = new List<Color>();
     int redSpan = desColor.R - srcColor.R;
     int greenSpan = desColor.G - srcColor.G;
     int blueSpan = desColor.B - srcColor.B;
     for (int i = 0; i < count; i++)
     {
       Color color = Color.FromArgb(
         srcColor.R + (int)((double)i / count * redSpan),
         srcColor.G + (int)((double)i / count * greenSpan),
         srcColor.B + (int)((double)i / count * blueSpan)
       );
       colorFactorList.Add(color);
     }
     return colorFactorList;
   }

**这里就是将红到紫之间的颜色分为5个区间，利用上面的算法拼接5个区间的分度值，就得到全彩颜色集合**
/// <summary>
   /// 获取从红到紫的颜色段的颜色集合
   /// </summary>
   /// <param name="totalCount">分度数</param>
   /// <param name="redToPurple">是否从红到紫色渐变</param>
   /// <returns>返回颜色集合</returns>
   public static List<Color> GetFullColorList(int totalCount, bool redToPurple = true)
   {
     List<Color> colorList = new List<Color>();
     if (totalCount > 0)
     {
       if (redToPurple)
       {
         colorList.AddRange(GetSingleColorList(Color.Red, Color.Yellow, totalCount / 5 + (totalCount ％ 5 > 0 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Yellow, Color.Lime, totalCount / 5 + (totalCount ％ 5 > 1 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Lime, Color.Cyan, totalCount / 5 + (totalCount ％ 5 > 2 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Cyan, Color.Blue, totalCount / 5 + (totalCount ％ 5 > 3 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Blue, Color.Magenta, totalCount / 5 + (totalCount ％ 5 > 4 ? 1 : 0)));
       }
       else
       {
         colorList.AddRange(GetSingleColorList(Color.Magenta, Color.Blue, totalCount / 5 + (totalCount ％ 5 > 0 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Blue, Color.Cyan, totalCount / 5 + (totalCount ％ 5 > 1 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Cyan, Color.Lime, totalCount / 5 + (totalCount ％ 5 > 2 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Lime, Color.Yellow, totalCount / 5 + (totalCount ％ 5 > 3 ? 1 : 0)));
         colorList.AddRange(GetSingleColorList(Color.Yellow, Color.Red, totalCount / 5 + (totalCount ％ 5 > 4 ? 1 : 0)));
       }
     }
     return colorList;
   }

以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。如有错误或未考虑完全的地方，望不吝赐教。

来源：https://blog.csdn.net/fanfan513/article/details/79970522