public class Thumbnail
{
private Image srcImage;
private string srcFileName;
/// <summary>
/// 创建
/// </summary>
/// <param name="FileName">原始图片路径</param>
public bool SetImage(string FileName)
{
srcFileName = FileName;
try
{
srcImage = Image.FromFile(srcFileName);
}
catch
{
return false;
}
return true;
}
/// <summary>
/// 回调
/// </summary>
/// <returns></returns>
public static bool ThumbnailCallback()
{
return false;
}
/// <summary>
/// 生成缩略图,返回缩略图的Image对象
/// </summary>
/// <param name="Width">缩略图宽度</param>
/// <param name="Height">缩略图高度</param>
/// <returns>缩略图的Image对象</returns>
public Image GetImage(int Width, int Height)
{
Image img;
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
img = srcImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);
return img;
}
/// <summary>
/// 保存缩略图
/// </summary>
/// <param name="Width"></param>
/// <param name="Height"></param>
public void SaveThumbnailImage(int Width, int Height)
{
switch (Path.GetExtension(srcFileName).ToLower())
{
case ".png":
SaveImage(Width, Height, ImageFormat.Png);
break;
case ".gif":
SaveImage(Width, Height, ImageFormat.Gif);
break;
default:
SaveImage(Width, Height, ImageFormat.Jpeg);
break;
}
}
/// <summary>
/// 生成缩略图并保存
/// </summary>
/// <param name="Width">缩略图的宽度</param>
/// <param name="Height">缩略图的高度</param>
/// <param name="imgformat">保存的图像格式</param>
/// <returns>缩略图的Image对象</returns>
public void SaveImage(int Width, int Height, ImageFormat imgformat)
{
if (imgformat != ImageFormat.Gif && (srcImage.Width > Width) || (srcImage.Height > Height))
{
Image img;
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
img = srcImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);
srcImage.Dispose();
img.Save(srcFileName, imgformat);
img.Dispose();
}
}
#region Helper
/// <summary>
/// 保存图片
/// </summary>
/// <param name="image">Image 对象</param>
/// <param name="savePath">保存路径</param>
/// <param name="ici">指定格式的编解码参数</param>
private static void SaveImage(Image image, string savePath, ImageCodecInfo ici)
{
//设置 原图片 对象的 EncoderParameters 对象
EncoderParameters parameters = new EncoderParameters(1);
parameters.Param[0] = new EncoderParameter(Encoder.Quality, ((long)100));
image.Save(savePath, ici, parameters);
parameters.Dispose();
}
/// <summary>
/// 获取图像编码解码器的所有相关信息
/// </summary>
/// <param name="mimeType">包含编码解码器的多用途网际邮件扩充协议 (MIME) 类型的字符串</param>
/// <returns>返回图像编码解码器的所有相关信息</returns>
private static ImageCodecInfo GetCodecInfo(string mimeType)
{
ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders();
foreach (ImageCodecInfo ici in CodecInfo)
{
if (ici.MimeType == mimeType)
return ici;
}
return null;
}
/// <summary>
/// 计算新尺寸
/// </summary>
/// <param name="width">原始宽度</param>
/// <param name="height">原始高度</param>
/// <param name="maxWidth">最大新宽度</param>
/// <param name="maxHeight">最大新高度</param>
/// <returns></returns>
private static Size ResizeImage(int width, int height, int maxWidth, int maxHeight)
{
decimal MAX_WIDTH = (decimal)maxWidth;
decimal MAX_HEIGHT = (decimal)maxHeight;
decimal ASPECT_RATIO = MAX_WIDTH / MAX_HEIGHT;
int newWidth, newHeight;
decimal originalWidth = (decimal)width;
decimal originalHeight = (decimal)height;
if (originalWidth > MAX_WIDTH || originalHeight > MAX_HEIGHT)
{
decimal factor;
// determine the largest factor
if (originalWidth / originalHeight > ASPECT_RATIO)
{
factor = originalWidth / MAX_WIDTH;
newWidth = Convert.ToInt32(originalWidth / factor);
newHeight = Convert.ToInt32(originalHeight / factor);
}
else
{
factor = originalHeight / MAX_HEIGHT;
newWidth = Convert.ToInt32(originalWidth / factor);
newHeight = Convert.ToInt32(originalHeight / factor);
}
}
else
{
newWidth = width;
newHeight = height;
}
return new Size(newWidth, newHeight);
}
/// <summary>
/// 得到图片格式
/// </summary>
/// <param name="name">文件名称</param>
/// <returns></returns>
public static ImageFormat GetFormat(string name)
{
string ext = name.Substring(name.LastIndexOf(".") + 1);
switch (ext.ToLower())
{
case "jpg":
case "jpeg":
return ImageFormat.Jpeg;
case "bmp":
return ImageFormat.Bmp;
case "png":
return ImageFormat.Png;
case "gif":
return ImageFormat.Gif;
default:
return ImageFormat.Jpeg;
}
}
#endregion
/// <summary>
/// 制作小正方形
/// </summary>
/// <param name="fileName">原图的文件路径</param>
/// <param name="newFileName">新地址</param>
/// <param name="newSize">长度或宽度</param>
public static void MakeSquareImage(string fileName, string newFileName, int newSize)
{
Image image = Image.FromFile(fileName);
int i = 0;
int width = image.Width;
int height = image.Height;
if (width > height)
i = height;
else
i = width;
Bitmap b = new Bitmap(newSize, newSize);
try
{
Graphics g = Graphics.FromImage(b);
g.InterpolationMode = InterpolationMode.High;
g.SmoothingMode = SmoothingMode.HighQuality;
//清除整个绘图面并以透明背景色填充
g.Clear(Color.Transparent);
if (width < height)
g.DrawImage(image, new Rectangle(0, 0, newSize, newSize), new Rectangle(0, (height - width) / 2, width, width), GraphicsUnit.Pixel);
else
g.DrawImage(image, new Rectangle(0, 0, newSize, newSize), new Rectangle((width - height) / 2, 0, height, height), GraphicsUnit.Pixel);
SaveImage(b, newFileName, GetCodecInfo("image/" + GetFormat(fileName).ToString().ToLower()));
}
finally
{
image.Dispose();
b.Dispose();
}
}
/// <summary>
/// 制作缩略图
/// </summary>
/// <param name="fileName">原图路径</param>
/// <param name="newFileName">新图路径</param>
/// <param name="maxWidth">最大宽度</param>
/// <param name="maxHeight">最大高度</param>
public static void MakeThumbnailImage(string fileName, string newFileName, int maxWidth, int maxHeight)
{
Image original = Image.FromFile(fileName);
Size _newSize = ResizeImage(original.Width, original.Height, maxWidth, maxHeight);
Image displayImage = new Bitmap(original, _newSize);
try
{
displayImage.Save(newFileName, GetFormat(fileName));
}
finally
{
original.Dispose();
}
}
/// <summary>
/// 生成缩略图,返回缩略图的Image对象
/// </summary>
/// <param name="rawImage">原始图片</param>
/// <param name="Width">缩略图宽度</param>
/// <param name="Height">缩略图高度</param>
/// <returns>缩略图的Image对象</returns>
public static Image MakeThumbnailImage(Image rawImage, int Width, int Height)
{
if (rawImage.Width == Width && rawImage.Height == Height)
{
return rawImage;
}
else
{
Size _newSize = new Size(Width, Height);
return new Bitmap(rawImage, _newSize);
}
}
/// <summary>
/// 将字节数组转换为图片
/// </summary>
/// <returns></returns>
public static Image GetImageByBytes(byte[] bytes)
{
Image photo = null;
if (bytes != null && !bytes.Equals(null))
{
using (MemoryStream ms = new MemoryStream(bytes))
{
try
{
photo = Image.FromStream(ms, true);
}
catch
{
}
}
}
return photo;
}
/// <summary>
/// 转化图片为Byte数组
/// </summary>
/// <param name="pb"></param>
/// <returns></returns>
public static byte[] GetBytesByImage(Image pb)
{
byte[] photo_byte = null;
if (pb != null)
{
using (MemoryStream ms = new MemoryStream())
{
Bitmap bmp = new Bitmap(pb);
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
photo_byte = new byte[ms.Length];
ms.Position = 0;
ms.Read(photo_byte, 0, Convert.ToInt32(ms.Length));
bmp.Dispose();
}
}
return photo_byte;
}
}
