WPF绘制圆形调色盘

		private void RenderColorPicker(double brightness){bitmap = new WriteableBitmap(radius * 2 + 20, radius * 2 + 20, 96.0, 96.0, PixelFormats.Pbgra32, null);Utility.DrawingAllPixel(bitmap, (x, y) =>{RGBColor rgb = new RGBColor(255, 255, 255, 0);double H = 0;Vector vector = Point.Subtract(new Point(x, y), new Point(radius + 10, radius + 10));var angle = Math.Atan(vector.Y / vector.X) * 180 / Math.PI;if (vector.X < 0){H = 270 + angle;}else if (vector.X > 0){H = 90 + angle;}else{if (vector.Y < 0){H = 0;}else if (vector.Y > 0){H = 180;}else{return new RGBColor(255, (int)(255 * brightness), (int)(255 * brightness), (int)(255 * brightness));}}//计算饱和度double S;if (vector.Length >= radius){S = 1;}else{S = vector.Length / radius;}//亮度值double B = brightness;return new HSBColor(H, S, B).RgbColor;});this.img.Source = bitmap;}				/// <summary>/// 绘制所有像素/// </summary>/// <param name="bitmap"></param>/// <param name="action"></param>public static void DrawingAllPixel(WriteableBitmap bitmap, Func<int, int, RGBColor> func){//跨距 ：针对跨距(stride)的计算，WritePixels()方法需要跨距。//从技术角度看，跨距是每行像素数据需要的字节数量。//可通过将每行中像素的数量乘上所使用格式的每像素位数(通常为4，如本例使用的Bgra32格式)//然后将所得结果除以8，进而将其从位数转换成字节数。int stride = bitmap.PixelWidth * bitmap.Format.BitsPerPixel / 8;for (int y = 0; y < bitmap.PixelHeight; y++){for (int x = 0; x < bitmap.PixelWidth; x++){var rgb = func.Invoke(x, y);byte[] colorData = new byte[4] { (byte)rgb.B, (byte)rgb.G, (byte)rgb.R, (byte)rgb.A };bitmap.WritePixels(new Int32Rect(x, y, 1, 1), colorData, stride, 0);}}}