C# 处理图片的总结

 private static void Deal_Sku_Image(string sImageFileName)
        {
            using (FileStream fs = new FileStream(sImageFileName, FileMode.Open, FileAccess.Read))
            {

                Image image = Image.FromStream(fs);
                
                    Bitmap b = new Bitmap(480, 480);
                    Graphics g = Graphics.FromImage(b);
                    g.InterpolationMode = InterpolationMode.Default;
                    g.DrawImage(image, 0, 0, 480, 480);
                    g.Dispose();
                    b.Save(sImageFileName + "_temp");
                    b.Dispose();

                    fs.Close();
                    File.Delete(sImageFileName);
                    File.Move(sImageFileName + "_temp", sImageFileName);
                

            }
        }

获取图片多少M

  //返回Mb
        public static double getImageSize(string path)
        {
            FileInfo fileInfo = new FileInfo(path);
            double length = Convert.ToDouble(fileInfo.Length);
            double Size = length / 1024 / 1024;
            return Size;

        }

图片转Base64

  public static string ImageToBase64(string fileFullName)
        {
            try
            {
                Bitmap bmp = new Bitmap(fileFullName);
                MemoryStream ms = new MemoryStream();
                bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                byte[] arr = new byte[ms.Length]; ms.Position = 0;
                ms.Read(arr, 0, (int)ms.Length); ms.Close();
                return Convert.ToBase64String(arr);
            }
            catch (Exception ex)
            {
                return null;
            }
        }

无损压缩图片

/// <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 = 800, bool sfsc = true)
        {
            //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;
            }
            Image iSource = Image.FromFile(sFile);
            ImageFormat tFormat = iSource.RawFormat;
            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();
            }
        }

判断图片是否空白图

 /// <summary>
        /// 检查图片是否空白图片
        /// </summary>
        /// <param name="img">Image</param>
        /// <returns>是否空白图片</returns>
        public static bool CheckTransparentImg(Image img)
        {
            bool blnIsTransparent = false;
            //加载位图
            Bitmap bitMap = new Bitmap(img);
            //图片总像素
            int intAll = img.Height * img.Width;
            int intCount = 0;
            //按像素遍历
            for (int intY = 0; intY < img.Height; intY++)
            {
                for (int intX = 0; intX < img.Width; intX++)
                {
                    if( bitMap.GetPixel(intX, intY).GetBrightness() < 0.2)
                    {
                        intCount += 1;
                    }
                }
            }

            
            //释放资源
            bitMap.Dispose();
            
            if (intCount < 200)
            {
                blnIsTransparent = true;
            }
            return blnIsTransparent;
        }