C# 图片无损压缩
这两天忙于将扫描仪扫描出来的文件缩放图片分辨率和大小,开始尝试修改扫描仪设置的参数,结果发现没有办法修改扫描仪参数,最后尝试将扫描后的图片进行代码处理,下面是写的是关于图片进行无损压缩的代码。
1 /// <summary> 2 /// 无损压缩图片 3 /// </summary> 4 /// <param name="sFile">原图片</param> 5 /// <param name="dFile">压缩后保存位置</param> 6 /// <param name="dHeight">高度</param> 7 /// <param name="dWidth">宽度</param> 8 /// <param name="flag">压缩质量 1-100</param> 9 /// <returns></returns> 10 public static bool CompressImage(string sFile, string dFile, int dHeight, int dWidth, int flag) 11 { 12 13 System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile); 14 ImageFormat tFormat = iSource.RawFormat; 15 int sW = 0, sH = 0; 16 //按比例缩放 17 Size tem_size = new Size(iSource.Width, iSource.Height); 18 19 if (tem_size.Width > dHeight ||tem_size.Width > dWidth) 20 { 21 if ((tem_size.Width * dHeight) > (tem_size.Height * dWidth)) 22 { 23 sW = dWidth; 24 sH = (dWidth * tem_size.Height) / tem_size.Width; 25 } 26 else 27 { 28 sH = dHeight; 29 sW = (tem_size.Width * dHeight) / tem_size.Height; 30 } 31 } 32 else 33 { 34 sW = tem_size.Width; 35 sH = tem_size.Height; 36 } 37 Bitmap ob = new Bitmap(dWidth, dHeight); 38 Graphics g = Graphics.FromImage(ob); 39 g.Clear(Color.WhiteSmoke); 40 g.CompositingQuality = CompositingQuality.HighQuality; 41 g.SmoothingMode = SmoothingMode.HighQuality; 42 g.InterpolationMode = InterpolationMode.HighQualityBicubic; 43 g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel); 44 g.Dispose(); 45 //以下代码为保存图片时,设置压缩质量 46 EncoderParameters ep = new EncoderParameters(); 47 long[] qy = new long[1]; 48 qy[0] = flag;//设置压缩的比例1-100 49 EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy); 50 ep.Param[0] = eParam; 51 try 52 { 53 ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders(); 54 ImageCodecInfo jpegICIinfo = null; 55 for (int x = 0; x < arrayICI.Length; x++) 56 { 57 if (arrayICI[x].FormatDescription.Equals("JPEG")) 58 { 59 jpegICIinfo = arrayICI[x]; 60 break; 61 } 62 } 63 if (jpegICIinfo != null) 64 { 65 ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径 66 } 67 else 68 { 69 ob.Save(dFile, tFormat); 70 } 71 return true; 72 } 73 catch 74 { 75 return false; 76 } 77 finally 78 { 79 iSource.Dispose(); 80 ob.Dispose(); 81 } 82 83 }
作者:Peter Luo
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