Swirl滤镜

Swirl Filter Swirl 滤镜是实现图像围绕中心点(cenX,cenY)扭曲旋转的效果，效果图如下： [](http://www.zealpixel.com/data/attachment/portal/201507/22/180505r368gml8r6yzlwdu.jpg) 原图 [](http://www.zealpixel.com/data/attachment/portal/201507/22/180503in1w3vgh3b3zhs8a.png) 效果图 代码如下： ~~~ /// Swirl Filter /// /// Source image. /// The X position of Swirl. /// The Y position of Swirl. /// The degree of swirl,0-360. /// The result image. private Bitmap SwirlFilterProcess(Bitmap srcBitmap, int cenX, int cenY, int swilDegree) { Bitmap a = new Bitmap(srcBitmap); int w = a.Width; int h = a.Height; int radius = 0; swilDegree = Math.Max(0, Math.Min(360, swilDegree)); double k = swilDegree / 3600.0; Bitmap dst = new Bitmap(w, h); System.Drawing.Imaging.BitmapData srcData = a.LockBits(new Rectangle(0, 0, w, h), System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppArgb); System.Drawing.Imaging.BitmapData dstData = dst.LockBits(new Rectangle(0, 0, w, h), System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppArgb); unsafe { byte* pIn = (byte*)srcData.Scan0.ToPointer(); byte* pOut = (byte*)dstData.Scan0.ToPointer(); byte* p = null; int stride = srcData.Stride - w * 4; int offsetX = 0, offsetY = 0; int newX = 0, newY = 0; double radian = 0; for (int y = 0; y < h; y++) { for (int x = 0; x < w; x++) { offsetX = x - cenX; offsetY = y - cenY; radian = Math.Atan2(offsetY, offsetX); radius = (int)(Math.Sqrt(offsetX * offsetX + offsetY * offsetY)); newX = (int)(radius * Math.Cos(radian + k * radius)) + cenX; newY = (int)(radius * Math.Sin(radian + k * radius)) + cenY; newX = Math.Min(w - 1, Math.Max(0, newX)); newY = Math.Min(h - 1, Math.Max(0, newY)); p = pIn + newY * srcData.Stride + newX * 4; pOut[0] = (byte)p[0]; pOut[1] = (byte)p[1]; pOut[2] = (byte)p[2]; pOut[3] = (byte)255; pOut += 4; } pOut += stride; } a.UnlockBits(srcData); dst.UnlockBits(dstData); } return dst; } ~~~ 最后放上一个完整的C#程序Demo下载地址：http://www.zealpixel.com/thread-58-1-1.html，另外，推荐一个网址www.zealpixel.com，有很多不错的图像处理开源代码！