using System.Collections.Generic;

　using System.Text;

　using System.IO;

　using System.Drawing;

　using System.Drawing.Imaging;

　namespace VjsdnPublishProject

　{

　public class CImageLibrary

　{

　public enum ValidateImageResult { OK, InvalidFileSize, InvalidImageSize }

　//检查图片大小

　public static ValidateImageResult ValidateImage(string file, int MAX_FILE_SIZE, int MAX_WIDTH, int MAX_HEIGHT)

　{

　byte[] bs = File.ReadAllBytes(file);

　double size = (bs.Length / 1024);

　//大于50KB

　if (size > MAX_FILE_SIZE) return ValidateImageResult.InvalidFileSize;

　Image img = Image.FromFile(file);

　if (img.Width > MAX_WIDTH || img.Height > MAX_HEIGHT) return ValidateImageResult.InvalidImageSize;

　return ValidateImageResult.OK;

　}

　//按宽度比例缩小图片

　public static Image GetOutputSizeImage(Image imgSource, int MAX_WIDTH)

　{

　Image imgOutput = imgSource;

　Size size = new Size(imgSource.Width, imgSource.Height);

　if (imgSource.Width <= 3 || imgSource.Height <= 3) return imgSource; //3X3大小的图片不转换

　if (imgSource.Width > MAX_WIDTH || imgSource.Height > MAX_WIDTH)

　{

　double rate = MAX_WIDTH / (double)imgSource.Width;

　if (imgSource.Height * rate > MAX_WIDTH)

　rate = MAX_WIDTH / (double)imgSource.Height;

　size.Width = Convert.ToInt32(imgSource.Width * rate);

　size.Height = Convert.ToInt32(imgSource.Height * rate);

　imgOutput = imgSource.GetThumbnailImage(size.Width, size.Height, null, IntPtr.Zero);

　}

　return imgOutput;

　}

　//按比例缩小图片

　public static Image GetOutputSizeImage(Image imgSource, Size outSize)

　{

　Image imgOutput = imgSource.GetThumbnailImage(outSize.Width, outSize.Height, null, IntPtr.Zero);

　return imgOutput;

　}

　/// <summary>

　/// 由图片文件转字节

　/// </summary>

　public static byte[] GetImageBytes(string imageFileName)

　{

　Image img = Image.FromFile(imageFileName);

　return GetImageBytes(img);

　}

　/// <summary>

　/// 图片转字节

　/// </summary>

　public static byte[] GetImageBytes(Image img)

　{

　if (img == null) return null;

　try

　{

　System.IO.MemoryStream ms = new MemoryStream();

　img.Save(ms, ImageFormat.Jpeg);

　byte[] bs = ms.ToArray();

　ms.Close();

　return bs;

　}

　catch { return null; }

　}

　/// <summary>

　/// 字节转图片

　/// </summary>

　public static Image FromBytes(byte[] bs)

　{

　if (bs == null) return null;

　try

　{

　MemoryStream ms = new MemoryStream(bs);

　Image returnImage = Image.FromStream(ms);

　ms.Close();

　return returnImage;

　}

　catch { return null; }

　}

　/// <summary>

　/// 将其它格式的图片转为JPG文件

　/// </summary>

　public static Image ToJPG(Image source)

　{

　//注意，先定义Bitmap类，否则会报A generic error occurred in GDI+

　Bitmap bmp = new Bitmap(source);

　MemoryStream ms = new MemoryStream();

　bmp.Save(ms, ImageFormat.Jpeg);

　return Bitmap.FromStream(ms);

　}

　/// <summary>

　/// 将其它格式的图片转为PNG文件

　/// </summary>

　public static Image ToPNG(Image source)

　{

　//注意，先定义Bitmap类，否则会报A generic error occurred in GDI+

　Bitmap bmp = new Bitmap(source);

　MemoryStream ms = new MemoryStream();

　bmp.Save(ms, ImageFormat.Png);

　return FromBytes(ms.ToArray());

　}

　//保存文件

　public static void SaveFile(string fileName, Image source)

　{

　source.Save(fileName, source.RawFormat);

　}

　}

　}