ASP.NET 生成高质量缩略图代码

asp.net应用越来越广，方方面面都得到了应用，来看一个ASP.NET 生成缩略图代码

 private static Size NewSize(int maxWidth, int maxHeight, int width, int height) { double w = 0.0; double h = 0.0; double sw = Convert.ToDouble(width); double sh = Convert.ToDouble(height); double mw = Convert.ToDouble(maxWidth); double mh = Convert.ToDouble(maxHeight); if ( sw < mw && sh < mh ) { w = sw; h = sh; } else if ( (sw/sh) > (mw/mh) ) { w = maxWidth; h = (w * sh)/sw; } else { h = maxHeight; w = (h * sw)/sh; } return new Size(Convert.ToInt32(w), Convert.ToInt32(h)); } public static void SendSmallImage(string fileName, string newFile, int maxHeight, int maxWidth) { System.Drawing.Image img = System.Drawing.Image.FromFile(fileName); System.Drawing.Imaging.ImageFormat thisFormat = img.RawFormat; Size newSize = NewSize(maxWidth, maxHeight, img.Width, img.Height); Bitmap outBmp = new Bitmap(newSize.Width, newSize.Height); Graphics g = Graphics.FromImage(outBmp); // 设置画布的描绘质量 g.CompositingQuality = CompositingQuality.HighQuality; g.SmoothingMode = SmoothingMode.HighQuality; g.InterpolationMode = InterpolationMode.HighQualityBicubic; g.DrawImage(img, new Rectangle(0, 0, newSize.Width, newSize.Height), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel); g.Dispose(); // 以下代码为保存图片时，设置压缩质量 EncoderParameters encoderParams = new EncoderParameters(); long[] quality = new long[1]; quality[0] = 100; EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality); encoderParams.Param[0] = encoderParam; //获得包含有关内置图像编码解码器的信息的ImageCodecInfo 对象。 ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders(); ImageCodecInfo jpegICI = null; for (int x = 0; x < arrayICI.Length; x++) { if (arrayICI[x].FormatDescription.Equals("JPEG")) { jpegICI = arrayICI[x];//设置JPEG编码 break; } } if (jpegICI != null) { outBmp.Save(newFile, jpegICI, encoderParams); } else { outBmp.Save(newFile, thisFormat); } img.Dispose(); outBmp.Dispose(); }