UWP取出图片主色调
一切都要从风车动漫的新详情页说起...
当我最初拿到风车动漫新详情页的UI设计概念图时,新详情页中有两点：
1.图片的高斯模糊
2.取出图片的主色调(主要用于tag和相关动漫的标题背景)
大概就是要这样：
由于高斯模糊是最近一个比较热门的东西，所以用的人比较多，也早就有大大给写好了UWP可用的版本
(参考)http://www.cnblogs.com/hebeiDGL/p/5427746.html
但是取出颜色的主色调明显就没有了...
最后在网上找到了这一篇帖子
http://bbs.csdn.net/topics/390773598
其中给出了一个通用的取颜色主色调的C#代码：
Color get_major_color(Bitmap bitmap) { //色调的总和 var sum_hue = 0d; //色差的阈值 var threshold = 30; //计算色调总和 for (int h = 0; h < bitmap.Height; h++) { for (int w = 0; w < bitmap.Width; w++) { var hue = bitmap.GetPixel(w, h).GetHue(); sum_hue += hue; } } var avg_hue = sum_hue / (bitmap.Width * bitmap.Height); //色差大于阈值的颜色值 var rgbs = new List<Color>(); for (int h = 0; h < bitmap.Height; h++) { for (int w = 0; w < bitmap.Width; w++) { var color = bitmap.GetPixel(w, h); var hue = color.GetHue(); //如果色差大于阈值，则加入列表 if (Math.Abs(hue - avg_hue) > threshold) { rgbs.Add(color); } } } if (rgbs.Count == 0) return Color.Black; //计算列表中的颜色均值，结果即为该图片的主色调 int sum_r = 0, sum_g = 0, sum_b = 0; foreach (var rgb in rgbs) { sum_r += rgb.R; sum_g += rgb.G; sum_b += rgb.B; } return Color.FromArgb(sum_r / rgbs.Count, sum_g / rgbs.Count, sum_b / rgbs.Count); }
嗯，看起来很好，但是UWP上并没有Bitmap这个类...
关于这个类，最重要的就是其中的"GetPixel"和"GetHue"这两个方法了,可以取出指定像素点的色调，但是显然...WP并没有实现的方法
后来仔细查找，发现了实现高斯模糊滤镜的代码中的一个很NB的类：MyImage
里面提供了两个方法：
1.getRComponent取出指定点的Red值(当然对应的还有G和B)
2.RgbTranToHsl 将RGB值转化为HSL值，返回一个int数组，int的012元素分别对应h,s,l
这样一下子就感受到了解决的希望...
于是我往MyImage类里面补充了一个方法：
public int getPixelHue(int x, int y) { int[] i = RgbTranToHsl(getRComponent(x, y), getGComponent(x, y), getBComponent(x, y)); return i[0]; }
并且修改了前面的取主色调的代码，把里面的Bitmap类全换成了WriteableBitmap：
public static Color GetMajorColor(WriteableBitmap bitmap) { MyImage mi = new MyImage(bitmap); //色调的总和 var sum_hue = 0d; //色差的阈值 var threshold = 30; //计算色调总和 for (int h = 0; h < bitmap.PixelHeight; h++) { for (int w = 0; w < bitmap.PixelWidth; w++) { var hue = mi.getPixelHue(w, h); sum_hue += hue; } } var avg_hue = sum_hue / (bitmap.PixelWidth * bitmap.PixelHeight); //色差大于阈值的颜色值 var rgbs = new List<Color>(); for (int h = 0; h < bitmap.PixelHeight; h++) { for (int w = 0; w < bitmap.PixelWidth; w++) { var hue = mi.getPixelHue(w, h); //如果色差大于阈值，则加入列表 if (Math.Abs(hue - avg_hue) > threshold) { rgbs.Add(Color.FromArgb(255, Convert.ToByte(mi.getRComponent(w, h)), Convert.ToByte(mi.getGComponent(w, h)), Convert.ToByte(mi.getBComponent(w, h)))); } } } if (rgbs.Count == 0) return Colors.Black; //计算列表中的颜色均值，结果即为该图片的主色调 int sum_r = 0, sum_g = 0, sum_b = 0; foreach (var rgb in rgbs) { sum_r += rgb.R; sum_g += rgb.G; sum_b += rgb.B; } return Color.FromArgb(255, Convert.ToByte(sum_r / rgbs.Count), Convert.ToByte(sum_g / rgbs.Count), Convert.ToByte(sum_b / rgbs.Count)); }
最后运行，成功了！(效果图详参开头)
附上完整版(代码我都进行了整合，可能有点乱...)的代码：
namespace Image { public class MyImage { //original bitmap image public WriteableBitmap image; //public WriteableBitmap destImage; //format of image (jpg/png) private String formatName; //dimensions of image private int width, height; // RGB Array Color public int[] colorArray; public MyImage(WriteableBitmap img) { this.image = img;// img.Clone(); Silverlight中的 WriteableBitmap 有 Clone()方法，win runtime 中的 WriteableBitmap没有该方法。在调用该构造函数时，可以调用自定义的 Utility.BitmapClone(wb) 方法来实现对原对象的“拷贝” formatName = "jpg"; width = img.PixelWidth; height = img.PixelHeight; updateColorArray(); } public MyImage clone() { return new MyImage(this.image); } /** * Method to reset the image to a solid color * @param color - color to rest the entire image to */ public void clearImage(int color) { for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) { setPixelColor(x, y, color); } } } /** * Set color array for image - called on initialisation * by constructor * * @param bitmap */ private void updateColorArray() { #region 原 //colorArray = image.Pixels; //int r, g, b; //for (int y = 0; y < height; y++) //{ // for (int x = 0; x < width; x++) // { // int index = y * width + x; // r = (colorArray[index] >> 16) & 0xff; // g = (colorArray[index] >> 8) & 0xff; // b = colorArray[index] & 0xff; // colorArray[index] = (255 << 24) | (r << 16) | (g << 8) | b; // } //} #endregion #region 段光磊 // 戴震军 ： https://github.net/daizhenjun/ImageFilterForWindowsPhone // WriteableBitmap.PixelBuffer property ：https://msdn.microsoft.net/en-us/library/windows/apps/windows.ui.xaml.media.imaging.writeablebitmap.pixelbuffer.aspx // WriteableBitmap class : https://msdn.microsoft.net/en-us/library/windows/apps/windows.ui.xaml.media.imaging.writeablebitmap.aspx // WriteableBitmapEx : http://writeablebitmapex.codeplex.net/releases/view/612952 // Getting Pixels of an Element(WriteableBitmap) // https://social.msdn.microsoft.net/Forums/en-US/39b3c702-caed-47e4-b7d3-b51d75cbca9b/getting-pixels-of-an-element-writeablebitmap?forum=winappswithcsharp // Windows 8 WriteableBitmap Pixel Arrays in C# and C++ : http://www.tuicool.net/articles/fQNvUz // 各种流转换 ： http://www.cnblogs.net/hebeiDGL/p/3428743.html // XAML images sample ： https://code.msdn.microsoft.net/windowsapps/0f5d56ae-5e57-48e1-9cd9-993115b027b9/ // 重新想象 Windows 8 Store Apps (29) - 图片处理 ： http://www.cnblogs.net/webabcd/archive/2013/05/27/3101069.html // 把 uwp 的 WriteableBitmap 对象的 PixelBuffer属性（IBuffer）转换为 byte[] 数组 byte[] colorBytes = BufferToBytes(image.PixelBuffer); // 转换为 silverlight 的 int[] 数组时，长度为 byte[] 数组的四分之一 colorArray = new int[colorBytes.Length / 4]; int a, r, g, b; int i = 0; // 通过 i 自加，来遍历 byte[] 整个数组 // 通过图片的宽、高，分别设置 int[] 数组中每个像素的 ARGB 信息 for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) { // int[] 数组的索引 int index = y * width + x; b = colorBytes[i++]; // Blue g = colorBytes[i++]; // Green r = colorBytes[i++]; // Red a = colorBytes[i++]; // Alpha colorArray[index] = (a << 24) | (r << 16) | (g << 8) | b; // 4个 byte值存储为一个 int 值 } } // msdn : https://msdn.microsoft.net/en-us/library/windows/apps/windows.ui.xaml.media.imaging.writeablebitmap.aspx //Stream stream = image.PixelBuffer.AsStream(); //using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read)) //{ // BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream); // // Scale image to appropriate size // BitmapTransform transform = new BitmapTransform() // { // ScaledWidth = Convert.ToUInt32(Scenario4WriteableBitmap.PixelWidth), // ScaledHeight = Convert.ToUInt32(Scenario4WriteableBitmap.PixelHeight) // }; // PixelDataProvider pixelData = await decoder.GetPixelDataAsync( // BitmapPixelFormat.Bgra8, // WriteableBitmap uses BGRA format // BitmapAlphaMode.Straight, // transform, // ExifOrientationMode.IgnoreExifOrientation, // This sample ignores Exif orientation // ColorManagementMode.DoNotColorManage // ); // // An array containing the decoded image data, which could be modified before being displayed // byte[] sourcePixels = pixelData.DetachPixelData(); // // Open a stream to copy the image contents to the WriteableBitmap's pixel buffer // using (Stream stream = Scenario4WriteableBitmap.PixelBuffer.AsStream()) // { // await stream.WriteAsync(sourcePixels, 0, sourcePixels.Length); // } //} //PixelDataProvider dp = await BitmapDecoder.CreateAsync(image.PixelBuffer.a.AsStream()); //var length = image.PixelWidth * image.PixelHeight; //var data = image.PixelBuffer.ToArray(); //fixed (byte* srcPtr = data) //{ // fixed (int* dstPtr = colorArray) // { // for (var i = 0; i < length; i++) // { // dstPtr[i] = (srcPtr[i * 4 + 3] << 24) // | (srcPtr[i * 4 + 2] << 16) // | (srcPtr[i * 4 + 1] << 8) // | srcPtr[i * 4 + 0]; // } // } //} #endregion } static byte[] BufferToBytes(IBuffer buf) { using (var dataReader = DataReader.FromBuffer(buf)) { var bytes = new byte[buf.Capacity]; dataReader.ReadBytes(bytes); return bytes; } } /** * Method to set the color of a specific pixel * * @param x * @param y * @param color */ public void setPixelColor(int x, int y, int color) { colorArray[((y * image.PixelWidth + x))] = color; //image.setPixel(x, y, color); //destImage.setPixel(x, y, colorArray[((y*image.getWidth()+x))]); } /** * Get the color for a specified pixel * * @param x * @param y * @return color */ public int getPixelColor(int x, int y) { return colorArray[y * width + x]; } private int[] RgbTranToHsl(int R, int G, int B) { int hVALUE, sVALUE, lVALUE; // RGB空间到HSL空间的转换 double Delta, CMax, CMin; double Red, Green, Blue, Hue, Sat, Lum; Red = (double)R / 255; Green = (double)G / 255; Blue = (double)B / 255; CMax = Math.Max(Red, Math.Max(Green, Blue)); CMin = Math.Min(Red, Math.Min(Green, Blue)); //计算hsb //Lum = (CMax + CMin) / 2; if (CMax == CMin) { Sat = 0; Hue = 0; } else { //计算hsb //if (Lum < 0.5) // Sat = (CMax - CMin) / (CMax + CMin); //else // Sat = (CMax - CMin) / (2 - CMax - CMin); //计算hsv（彩色空间） if (CMax == 0) { Sat = 0; } else { Sat = 1 - CMin / CMax; } Delta = CMax - CMin; if (Red == CMax) { Hue = (Green - Blue) / Delta; } else if (Green == CMax) { Hue = 2 + (Blue - Red) / Delta; } else { Hue = 4.0 + (Red - Green) / Delta; } Hue = Hue / 6; if (Hue < 0) Hue = Hue + 1; } hVALUE = (int)Math.Round(Hue * 360); sVALUE = (int)Math.Round(Sat * 100); lVALUE = (int)Math.Round(CMax * 100); int[] HSL = new int[3] { hVALUE, sVALUE, lVALUE }; return HSL; //lvalue = (int)Math.Round(Lum * 100); } public int getPixelHue(int x, int y) { int[] i = RgbTranToHsl(getRComponent(x, y), getGComponent(x, y), getBComponent(x, y)); return i[0]; } /** * Set the color of a specified pixel from an RGB combo * * @param x * @param y * @param c0 * @param c1 * @param c2 */ public void setPixelColor(int x, int y, int c0, int c1, int c2) { int rgbcolor = (255 << 24) + (c0 << 16) + (c1 << 8) + c2; colorArray[((y * image.PixelWidth + x))] = rgbcolor; //int array = ((y*image.getWidth()+x)); //vbb.order(ByteOrder.nativeOrder()); //vertexBuffer = vbb.asFloatBuffer(); //vertexBuffer.put(vertices); //vertexBuffer.position(0); //image.setPixel(x, y, colorArray[((y*image.getWidth()+x))]); } public void copyPixelsFromBuffer() { //从缓冲区中copy数据以加快像素处理速度 // this.destImage.Dispatcher.BeginInvoke(() => // { //var result = new WriteableBitmap(width, height); //Buffer.BlockCopy(colorArray, 0, destImage.Pixels, 0, colorArray.Length * 4); // 段光磊注释掉 //return result; // }); } /** * Method to get the RED color for the specified * pixel * @param x * @param y * @return color of R */ public int getRComponent(int x, int y) { return (getColorArray()[((y * width + x))] & 0x00FF0000) >> 16; } /** * Method to get the GREEN color for the specified * pixel * @param x * @param y * @return color of G */ public int getGComponent(int x, int y) { return (getColorArray()[((y * width + x))] & 0x0000FF00) >> 8; } /** * Method to get the BLUE color for the specified * pixel * @param x * @param y * @return color of B */ public int getBComponent(int x, int y) { return (getColorArray()[((y * width + x))] & 0x000000FF); } /** * @return the image */ //public WriteableBitmap getImage() //{ // //return image; // return destImage; //} /** * @param image the image to set */ public void setImage(WriteableBitmap image) { this.image = image; } /** * @return the formatName */ public String getFormatName() { return formatName; } /** * @param formatName the formatName to set */ public void setFormatName(String formatName) { this.formatName = formatName; } /** * @return the width */ public int getWidth() { return width; } /** * @param width the width to set */ public void setWidth(int width) { this.width = width; } /** * @return the height */ public int getHeight() { return height; } /** * @param height the height to set */ public void setHeight(int height) { this.height = height; } /** * @return the colorArray */ public int[] getColorArray() { return colorArray; } /** * @param colorArray the colorArray to set */ public void setColorArray(int[] colorArray) { this.colorArray = colorArray; } public static int SAFECOLOR(int a) { if (a < 0) return 0; else if (a > 255) return 255; else return a; } public static int rgb(int r, int g, int b) { return (255 << 24) + (r << 16) + (g << 8) + b; } public static MyImage LoadImage(string path) { //Uri uri = new Uri(path, UriKind.Relative); //StreamResourceInfo resourceInfo = Application.GetResourceStream(uri); //BitmapImage bmp = new BitmapImage(); //bmp.SetSource(resourceInfo.Stream); //return new Image(new WriteableBitmap(bmp)); return null; } } class Utility { /// <summary> /// WriteableBitmap 的拷贝 /// </summary> /// <param name="bitmap">原</param> /// <returns></returns> public static async Task<WriteableBitmap> BitmapClone(WriteableBitmap bitmap) { WriteableBitmap result = new WriteableBitmap(bitmap.PixelWidth, bitmap.PixelHeight); byte[] sourcePixels = Get_WriteableBitmap_bytes(bitmap); //byte[] resultPixels = new byte[sourcePixels.Length]; //sourcePixels.CopyTo(resultPixels, 0); using (Stream resultStream = result.PixelBuffer.AsStream()) { await resultStream.WriteAsync(sourcePixels, 0, sourcePixels.Length); } return result; } public static byte[] Get_WriteableBitmap_bytes(WriteableBitmap bitmap) { // 获取对直接缓冲区的访问，WriteableBitmap 的每个像素都写入直接缓冲区。 IBuffer bitmapBuffer = bitmap.PixelBuffer; //byte[] sourcePixels = new byte[bitmapBuffer.Length]; //Windows.Security.Cryptography.CryptographicBuffer.CopyToByteArray(bitmapBuffer, out sourcePixels); //bitmapBuffer.CopyTo(sourcePixels); using (var dataReader = DataReader.FromBuffer(bitmapBuffer)) { var bytes = new byte[bitmapBuffer.Capacity]; dataReader.ReadBytes(bytes); return bytes; } } } public interface IImageFilter { MyImage process(MyImage imageIn); } public class GaussianBlurFilter : IImageFilter { protected static int Padding = 3; /// <summary> /// The bluriness factor. /// Should be in the range [0, 40]. /// </summary> public float Sigma = 0.75f; protected float[] ApplyBlur(float[] srcPixels, int width, int height) { float[] destPixels = new float[srcPixels.Length]; System.Array.Copy(srcPixels, 0, destPixels, 0, srcPixels.Length); int w = width + Padding * 2; int h = height + Padding * 2; // Calculate the coefficients float q = Sigma; float q2 = q * q; float q3 = q2 * q; float b0 = 1.57825f + 2.44413f * q + 1.4281f * q2 + 0.422205f * q3; float b1 = 2.44413f * q + 2.85619f * q2 + 1.26661f * q3; float b2 = -(1.4281f * q2 + 1.26661f * q3); float b3 = 0.422205f * q3; float b = 1.0f - ((b1 + b2 + b3) / b0); // Apply horizontal pass ApplyPass(destPixels, w, h, b0, b1, b2, b3, b); // Transpose the array float[] transposedPixels = new float[destPixels.Length]; Transpose(destPixels, transposedPixels, w, h); // Apply vertical pass ApplyPass(transposedPixels, h, w, b0, b1, b2, b3, b); // transpose back Transpose(transposedPixels, destPixels, h, w); return destPixels; } protected void ApplyPass(float[] pixels, int width, int height, float b0, float b1, float b2, float b3, float b) { float num = 1f / b0; int triplewidth = width * 3; for (int i = 0; i < height; i++) { int steplength = i * triplewidth; for (int j = steplength + 9; j < (steplength + triplewidth); j += 3) { pixels[j] = (b * pixels[j]) + ((((b1 * pixels[j - 3]) + (b2 * pixels[j - 6])) + (b3 * pixels[j - 9])) * num); pixels[j + 1] = (b * pixels[j + 1]) + ((((b1 * pixels[(j + 1) - 3]) + (b2 * pixels[(j + 1) - 6])) + (b3 * pixels[(j + 1) - 9])) * num); pixels[j + 2] = (b * pixels[j + 2]) + ((((b1 * pixels[(j + 2) - 3]) + (b2 * pixels[(j + 2) - 6])) + (b3 * pixels[(j + 2) - 9])) * num); } for (int k = ((steplength + triplewidth) - 9) - 3; k >= steplength; k -= 3) { pixels[k] = (b * pixels[k]) + ((((b1 * pixels[k + 3]) + (b2 * pixels[k + 6])) + (b3 * pixels[k + 9])) * num); pixels[k + 1] = (b * pixels[k + 1]) + ((((b1 * pixels[(k + 1) + 3]) + (b2 * pixels[(k + 1) + 6])) + (b3 * pixels[(k + 1) + 9])) * num); pixels[k + 2] = (b * pixels[k + 2]) + ((((b1 * pixels[(k + 2) + 3]) + (b2 * pixels[(k + 2) + 6])) + (b3 * pixels[(k + 2) + 9])) * num); } } } protected void Transpose(float[] input, float[] output, int width, int height) { for (int i = 0; i < height; i++) { for (int j = 0; j < width; j++) { int index = (j * height) * 3 + (i * 3); int pos = (i * width) * 3 + (j * 3); output[index] = input[pos]; output[index + 1] = input[pos + 1]; output[index + 2] = input[pos + 2]; } } } protected float[] ConvertImageWithPadding(MyImage imageIn, int width, int height) { int newheight = height + Padding * 2; int newwidth = width + Padding * 2; float[] numArray = new float[(newheight * newwidth) * 3]; int index = 0; int num = 0; for (int i = -3; num < newheight; i++) { int y = i; if (i < 0) { y = 0; } else if (i >= height) { y = height - 1; } int count = 0; int negpadding = -1 * Padding; while (count < newwidth) { int x = negpadding; if (negpadding < 0) { x = 0; } else if (negpadding >= width) { x = width - 1; } numArray[index] = imageIn.getRComponent(x, y) * 0.003921569f; numArray[index + 1] = imageIn.getGComponent(x, y) * 0.003921569f; numArray[index + 2] = imageIn.getBComponent(x, y) * 0.003921569f; count++; negpadding++; index += 3; } num++; } return numArray; } //@Override public virtual MyImage process(MyImage imageIn) { int width = imageIn.getWidth(); int height = imageIn.getHeight(); float[] imageArray = ConvertImageWithPadding(imageIn, width, height); imageArray = ApplyBlur(imageArray, width, height); int newwidth = width + Padding * 2; for (int i = 0; i < height; i++) { int num = ((i + 3) * newwidth) + 3; for (int j = 0; j < width; j++) { int pos = (num + j) * 3; imageIn.setPixelColor(j, i, (byte)(imageArray[pos] * 255f), (byte)(imageArray[pos + 1] * 255f), (byte)(imageArray[pos + 2] * 255f)); } } return imageIn; } } public class BlurEffect { WriteableBitmap wb; public BlurEffect(WriteableBitmap Image) { wb = Image; } /// <summary> /// /// </summary> /// <param name="level">[0,40]</param> public async Task<WriteableBitmap> ApplyFilter(float level) { #region old /* using (IRandomAccessStream fileStream = await file.OpenAsync(FileAccessMode.Read)) { BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream); // Scale image to appropriate size BitmapTransform transform = new BitmapTransform() { ScaledWidth = Convert.ToUInt32(wb.PixelWidth), ScaledHeight = Convert.ToUInt32(wb.PixelHeight) }; PixelDataProvider pixelData = await decoder.GetPixelDataAsync( BitmapPixelFormat.Bgra8, // WriteableBitmap uses BGRA format BitmapAlphaMode.Straight, transform, ExifOrientationMode.IgnoreExifOrientation, // This sample ignores Exif orientation ColorManagementMode.DoNotColorManage ); // An array containing the decoded image data, which could be modified before being displayed byte[] sourcePixels = pixelData.DetachPixelData(); using (Stream stream = wb.PixelBuffer.AsStream()) { await stream.WriteAsync(sourcePixels, 0, sourcePixels.Length); } } */ #endregion // 拷贝 WriteableBitmap new_bitmap = await Utility.BitmapClone(wb); // 添加高斯滤镜效果 MyImage mi = new MyImage(new_bitmap); GaussianBlurFilter filter = new GaussianBlurFilter(); filter.Sigma = level; filter.process(mi); // 图片添加完滤镜的 int[] 数组 int[] array = mi.colorArray; // byte[] 数组的长度是 int[] 数组的 4倍 byte[] result = new byte[array.Length * 4]; // 通过自加，来遍历 byte[] 数组中的值 int j = 0; for (int i = 0; i < array.Length; i++) { // 同时把 int 值中 a、r、g、b 的排列方式，转换为 byte数组中 b、g、r、a 的存储方式 result[j++] = (byte)(array[i]); // Blue result[j++] = (byte)(array[i] >> 8); // Green result[j++] = (byte)(array[i] >> 16); // Red result[j++] = (byte)(array[i] >> 24); // Alpha } // Open a stream to copy the image contents to the WriteableBitmap's pixel buffer using (Stream stream = new_bitmap.PixelBuffer.AsStream()) { await stream.WriteAsync(result, 0, result.Length); } return new_bitmap;// 把 WriteableBitmap 对象赋值给 Image 控件 // 用像素缓冲区的数据绘制图片 //new_bitmap.Invalidate(); } } public class GetColor { public static Color GetMajorColor(WriteableBitmap bitmap) { MyImage mi = new MyImage(bitmap); //色调的总和 var sum_hue = 0d; //色差的阈值 var threshold = 30; //计算色调总和 for (int h = 0; h < bitmap.PixelHeight; h++) { for (int w = 0; w < bitmap.PixelWidth; w++) { var hue = mi.getPixelHue(w, h); sum_hue += hue; } } var avg_hue = sum_hue / (bitmap.PixelWidth * bitmap.PixelHeight); //色差大于阈值的颜色值 var rgbs = new List<Color>(); for (int h = 0; h < bitmap.PixelHeight; h++) { for (int w = 0; w < bitmap.PixelWidth; w++) { var hue = mi.getPixelHue(w, h); //如果色差大于阈值，则加入列表 if (Math.Abs(hue - avg_hue) > threshold) { rgbs.Add(Color.FromArgb(255, Convert.ToByte(mi.getRComponent(w, h)), Convert.ToByte(mi.getGComponent(w, h)), Convert.ToByte(mi.getBComponent(w, h)))); } } } if (rgbs.Count == 0) return Colors.Black; //计算列表中的颜色均值，结果即为该图片的主色调 int sum_r = 0, sum_g = 0, sum_b = 0; foreach (var rgb in rgbs) { sum_r += rgb.R; sum_g += rgb.G; sum_b += rgb.B; } return Color.FromArgb(255, Convert.ToByte(sum_r / rgbs.Count), Convert.ToByte(sum_g / rgbs.Count), Convert.ToByte(sum_b / rgbs.Count)); } } }
使用方法：
//通过网页创建一个WriteableBitmap WriteableBitmap wb = new WriteableBitmap(1000, 1500); HttpClient hc = new HttpClient(); byte[] b = await hc.GetByteArrayAsync(url); using (IRandomAccessStream iras = b.AsBuffer().AsStream().AsRandomAccessStream()) { await wb.SetSourceAsync(iras); }
//高斯模糊 BlurEffect be = new BlurEffect(wb); BackgroundImage.Source = await be.ApplyFilter(10);//高斯模糊等级可以自己定义
//取主色调并应用到TagsTextBlock TagsTB.Foreground = new SolidColorBrush(GetColor.GetMajorColor(wb));
最后，参考博文：
