前文可以参考我的前一篇博文：C# .Net实现简易灰度图和酷炫HeatMap热力图winform
但是，先前的热力图效果，我并不满意。不满意的地方主要有三点：
因此，我做了改进，上一个图是之前的效果，下一个图是改进后的效果
//创建调色板，颜色映射
private ColorMap[] CreatePalette()
{
ColorMap[] colorMaps = new ColorMap[256];
List<Color> newColors = new List<Color>();
//颜色集合
newColors.AddRange(GetGradientColorList(Color.Red, Color.Yellow, 64));
newColors.AddRange(GetGradientColorList(Color.Yellow, Color.Green, 64));
newColors.AddRange(GetGradientColorList(Color.Green, Color.Blue, 64));
newColors.AddRange(GetGradientColorList(Color.Blue, Color.Navy, 64));
//颜色调色板展示
Bitmap colorBitmap = new Bitmap(colorPanel.Width, colorPanel.Height);
Graphics graphic = Graphics.FromImage(colorBitmap);
for (int i = 0; i < 256; i++)
{
SolidBrush solidBrush = new SolidBrush(newColors[i]);
Rectangle rectangle = new Rectangle((int)(i * 2), 0, (int)2, colorPanel.Height);
graphic.FillRectangle(solidBrush, rectangle);
graphic.Save();
solidBrush.Dispose();
}
colorPanel.BackgroundImage = colorBitmap;
// 遍历每个像素并创建一个新的颜色映射
for (int X = 0; X <= 255; X++)
{
colorMaps[X] = new ColorMap();
colorMaps[X].OldColor = System.Drawing.Color.FromArgb(X, X, X);
colorMaps[X].NewColor = System.Drawing.Color.FromArgb(255, newColors[X]);
}
return colorMaps;
}
/// <summary>
/// 获得两个颜色之间渐进颜色的集合
/// </summary>
/// <param name="sourceColor">起始颜色</param>
/// <param name="destColor">终止颜色</param>
/// <param name="count">渐进颜色的个数</param>
/// <returns>返回颜色集合</returns>
public static List<Color> GetGradientColorList(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;
}
private void DrawHeatPoint2(Graphics graphics, HeatPoint heatPoint)
{
Console.WriteLine("heatPoint.Intensity = " + heatPoint.Intensity);
int radius = 40 * (heatPoint.Intensity+6) / 240;
List<System.Drawing.Point> pointsList = new List<System.Drawing.Point>();
for (double degrees = 0; degrees <= 360; degrees += 10)
{
// 在定义半径的圆的圆周上绘制新点
// 使用点坐标、半径和角度
// 计算这个迭代点在圆上的位置
System.Drawing.Point point = new System.Drawing.Point();
point.X = Convert.ToInt32(heatPoint.X + radius * Math.Cos((Math.PI / 180) * degrees));
point.Y = Convert.ToInt32(heatPoint.Y + radius * Math.Sin((Math.PI / 180) * degrees));
pointsList.Add(point);
}
// 创建新的颜色混合来告诉 PathGradientBrush 使用什么颜色以及放置它们的位置
ColorBlend colorBlend = new ColorBlend(3);
colorBlend.Positions = new float[3] { 0, 0.8f, 1 };
colorBlend.Colors = new System.Drawing.Color[3]
{
System.Drawing.Color.FromArgb(0, System.Drawing.Color.White),
System.Drawing.Color.FromArgb(heatPoint.Intensity, System.Drawing.Color.Black),
System.Drawing.Color.FromArgb(heatPoint.Intensity, System.Drawing.Color.Black)
};
// 创建新的 PathGradientBrush 以使用圆周点创建径向渐变
PathGradientBrush brush = new PathGradientBrush(pointsList.ToArray());
// 将颜色混合传递给 PathGradientBrush 以指示它如何生成渐变
brush.InterpolationColors = colorBlend;
graphics.FillPolygon(brush, pointsList.ToArray());
//brush.Dispose();
}
四、更新视图
private void UpdateView()
{
//灰度
Bitmap bitmap1 = CreateIntensityMask(new Bitmap((int)panel1.Width, (int)panel1.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb), heatPoints, 1);
panel1.BackgroundImage = bitmap1;
//上色
panel3.BackgroundImage = Colorize(bitmap1);
}
private Bitmap CreateIntensityMask(Bitmap bitmap, List<HeatPoint> aHeatPoints)
{
//从Bitmap获得Graphics GDI+ 绘图图面
Graphics graphics = Graphics.FromImage(bitmap);
//清除整个绘图面并以白色填充
graphics.Clear(System.Drawing.Color.White);
foreach (HeatPoint point in aHeatPoints)
{
DrawHeatPoint2(graphics, point);
}
return bitmap;
}
