using System; using System.Collections.Generic; using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; namespace TestProject { public partial class test : System.Web.UI.Page { /// <summary> /// 无损压缩图片 /// </summary> /// <param name="sFile">原图片地址</param> /// <param name="dFile">压缩后保存图片地址</param> /// <param name="flag">压缩质量(数字越小压缩率越高)1-100</param> /// <param name="size">压缩后图片的最大大小</param> /// <param name="sfsc">是否是第一次调用</param> /// <returns></returns> public static bool CompressImage(string sFile, string dFile, int flag = 90, int size = 300, bool sfsc = true) { System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile); ImageFormat tFormat = iSource.RawFormat; //如果是第一次调用,原始图像的大小小于要压缩的大小,则直接复制文件,并且返回true FileInfo firstFileInfo = new FileInfo(sFile); if (sfsc == true && firstFileInfo.Length < size * 1024) { firstFileInfo.CopyTo(dFile); return true; } int dHeight = iSource.Height / 2; int dWidth = iSource.Width / 2; int sW = 0, sH = 0; //按比例缩放 Size tem_size = new Size(iSource.Width, iSource.Height); if (tem_size.Width > dHeight || tem_size.Width > dWidth) { if ((tem_size.Width * dHeight) > (tem_size.Width * dWidth)) { sW = dWidth; sH = (dWidth * tem_size.Height) / tem_size.Width; } else { sH = dHeight; sW = (tem_size.Width * dHeight) / tem_size.Height; } } else { sW = tem_size.Width; sH = tem_size.Height; } Bitmap ob = new Bitmap(dWidth, dHeight); Graphics g = Graphics.FromImage(ob); g.Clear(Color.WhiteSmoke); g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel); g.Dispose(); //以下代码为保存图片时,设置压缩质量 EncoderParameters ep = new EncoderParameters(); long[] qy = new long[1]; qy[0] = flag;//设置压缩的比例1-100 EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy); ep.Param[0] = eParam; try { ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders(); ImageCodecInfo jpegICIinfo = null; for (int x = 0; x < arrayICI.Length; x++) { if (arrayICI[x].FormatDescription.Equals("JPEG")) { jpegICIinfo = arrayICI[x]; break; } } if (jpegICIinfo != null) { ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径 FileInfo fi = new FileInfo(dFile); if (fi.Length > 1024 * size) { flag = flag - 10; CompressImage(sFile, dFile, flag, size, false); } } else { ob.Save(dFile, tFormat); } return true; } catch { return false; } finally { iSource.Dispose(); ob.Dispose(); } } } }
转载于:https://www.cnblogs.com/mengfangchao/p/7838676.html