在asp.net中,上傳圖片功能或者是常用的,生成縮略圖也是常用的。baidu或者google,c#的方法也是很多的,但是一用卻發現縮略圖不清晰啊,縮略圖片太大之類的事情,下面是我在處理圖片上的代碼,效果不錯,所以拿出來分享,(效果能達到一些繪圖軟件的效果)
代碼如下:
using System;using System.Drawing;using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Net;
using System.Web;
namespace IMartV3.UI.Common
{
/// <summary>
/// Thumbnail 的摘要說明。
/// </summary>
public class Thumbnail
{
private Image srcImage;
private string srcFileName;
/// <summary>
/// 創建
/// </summary>
/// <param name="FileName">原始圖片路徑</param>
public bool SetImage(string FileName,bool isMaped=false)
{
srcFileName = isMaped?FileName:HttpContext.Current.Server.MapPath(FileName);
try
{
srcImage = Image.FromFile(srcFileName);
}
catch
{
return false;
}
return true;
}
/// <summary>
/// 回調
/// </summary>
/// <returns></returns>
public bool ThumbnailCallback()
{
return false;
}
/// <summary>
/// 生成縮略圖,返回縮略圖的Image對象
/// </summary>
/// <param name="Width">縮略圖寬度</param>
/// <param name="Height">縮略圖高度</param>
/// <returns>縮略圖的Image對象</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>
/// 保存縮略圖
/// </summary>
/// <param name="Width"></param>
/// <param name="Height"></param>
public void SaveThumbnailImage(int Width,int Height,bool iscut=true)
{
if (iscut == false)
{
Size s = ResizeImage(srcImage.Width, srcImage.Height, Width, Height);
Width = s.Width;
Height = s.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>
/// 生成縮略圖並保存
/// </summary>
/// <param name="Width">縮略圖的寬度</param>
/// <param name="Height">縮略圖的高度</param>
/// <param name="imgformat">保存的圖像格式</param>
/// <returns>縮略圖的Image對象</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>
/// 保存圖片
/// </summary>
/// <param name="image">Image 對象</param>
/// <param name="savePath">保存路徑</param>
/// <param name="ici">指定格式的編解碼參數</param>
private static void SaveImage(Image image, string savePath, ImageCodecInfo ici)
{
SaveImage(image, savePath, ici, 80);
}
private static void SaveImage(Image image, string savePath, ImageCodecInfo ici, int quality)
{
//設置 原圖片 對象的 EncoderParameters 對象
EncoderParameters parameters = new EncoderParameters(1);
parameters.Param[0] = new EncoderParameter(Encoder.Quality, quality);
Directory.GetParent(savePath).Create();
try
{
image.Save(savePath, ici, parameters);
}
catch { }
parameters.Dispose();
}
/// <summary>
/// 獲取圖像編碼解碼器的所有相關信息
/// </summary>
/// <param name="mimeType">包含編碼解碼器的多用途網際郵件擴充協議 (MIME) 類型的字符串</param>
/// <returns>返回圖像編碼解碼器的所有相關信息</returns>
public static ImageCodecInfo GetCodecInfo(string mimeType)
{
ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders();
foreach(ImageCodecInfo ici in CodecInfo)
{
if(ici.MimeType == mimeType)
return ici;
}
return null;
}
/// <summary>
/// 計算新尺寸
/// </summary>
/// <param name="width">原始寬度</param>
/// <param name="height">原始高度</param>
/// <param name="maxWidth">最大新寬度</param>
/// <param name="maxHeight">最大新高度</param>
/// <returns></returns>
private static Size ResizeImage(int width, int height, int maxWidth, int maxHeight)
{
//此次2012-02-05修改過=================
if (maxWidth <= 0)
maxWidth = width;
if (maxHeight <= 0)
maxHeight = height;
//以上2012-02-05修改過=================
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>
/// 得到圖片格式
/// </summary>
/// <param name="name">文件名稱</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>
/// 製作小正方形
/// </summary>
/// <param name="image">圖片對象</param>
/// <param name="newFileName">新地址</param>
/// <param name="newSize">長度或寬度</param>
public static void MakeSquareImage(Image image, string newFileName, int newSize)
{
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);
//設置高質量插值法
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
//設置高質量,低速度呈現平滑程度
g.SmoothingMode = SmoothingMode.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
//清除整個繪圖面並以透明背景色填充
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(newFileName).ToString().ToLower()));
}
finally
{
image.Dispose();
b.Dispose();
}
}
/// <summary>
/// 製作小正方形
/// </summary>
/// <param name="fileName">圖片文件名</param>
/// <param name="newFileName">新地址</param>
/// <param name="newSize">長度或寬度</param>
public static void MakeSquareImage(string fileName, string newFileName, int newSize)
{
MakeSquareImage(Image.FromFile(fileName), newFileName, newSize);
}
/// <summary>
/// 製作遠程小正方形
/// </summary>
/// <param name="url">圖片url</param>
/// <param name="newFileName">新地址</param>
/// <param name="newSize">長度或寬度</param>
public static void MakeRemoteSquareImage(string url, string newFileName, int newSize)
{
Stream stream = GetRemoteImage(url);
if (stream == null)
return;
Image original = Image.FromStream(stream);
stream.Close();
MakeSquareImage(original, newFileName, newSize);
}
/// <summary>
/// 製作縮略圖
/// </summary>
/// <param name="original">圖片對象</param>
/// <param name="newFileName">新圖路徑</param>
/// <param name="maxWidth">最大寬度</param>
/// <param name="maxHeight">最大高度</param>
public static void MakeThumbnailImage(Image original, string newFileName, int maxWidth, int maxHeight)
{
MakeThumbnailImage(original, newFileName, maxWidth, maxHeight, 100);
}
public static void MakeThumbnailImage(Image original, string newFileName, int maxWidth, int maxHeight, int quality)
{
Size _newSize = ResizeImage(original.Width,original.Height,maxWidth, maxHeight);
using (Image displayImage = new Bitmap(original, _newSize))
{
try
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
ImageCodecInfo ici = null;
foreach (ImageCodecInfo codec in codecs)
{
if (original.RawFormat.Guid == codec.FormatID)
ici = codec;
}
EncoderParameters encoderParams = new EncoderParameters();
//long[] qualityParam = new long[1];
if (quality < 40 || quality > 100)
quality = 80;
//qualityParam[0] = quality;
encoderParams.Param[0] = new EncoderParameter(Encoder.Quality, quality);
//displayImage.Save(newFileName, original.RawFormat);
if (ici == null)
{
displayImage.Save(newFileName, original.RawFormat);
}
else
{
displayImage.Save(newFileName, ici, encoderParams);
}
}
catch
{
displayImage.Save(newFileName, original.RawFormat);
}
finally
{
original.Dispose();
}
}
}
/// <summary>
/// 製作縮略圖
/// </summary>
/// <param name="fileName">文件名</param>
/// <param name="newFileName">新圖路徑</param>
/// <param name="maxWidth">最大寬度</param>
/// <param name="maxHeight">最大高度</param>
public static void MakeThumbnailImage(string fileName, string newFileName, int maxWidth, int maxHeight)
{
//2012-02-05修改過,支持替換
byte[] imageBytes = File.ReadAllBytes(fileName);
Image img = Image.FromStream(new System.IO.MemoryStream(imageBytes));
MakeThumbnailImage(img, newFileName, maxWidth, maxHeight);
//原文
//MakeThumbnailImage(Image.FromFile(fileName), newFileName, maxWidth, maxHeight);
}
#region 2012-2-19 新增生成圖片縮略圖方法
/// <summary>
/// 生成縮略圖
/// </summary>
/// <param name="fileName">源圖路徑(絕對路徑)</param>
/// <param name="newFileName">縮略圖路徑(絕對路徑)</param>
/// <param name="width">縮略圖寬度</param>
/// <param name="height">縮略圖高度</param>
/// <param name="mode">生成縮略圖的方式</param>
public static void MakeThumbnailImage(string fileName, string newFileName, int width, int height, string mode)
{
MakeThumbnailImage(fileName, newFileName, width, height, mode, 80);
}
public static void MakeThumbnailImage(string fileName, string newFileName, int width, int height, string mode, int quality)
{
Bitmap bmp = null;
ImageFormat type = null;
MakeThumbnailImage(fileName, width, height, mode, out bmp, out type);
if (bmp != null && type!=null)
{
SaveImage(bmp, newFileName, GetCodecInfo("image/"+type.ToString().ToLower()), quality);
bmp.Dispose();
}
}
public static void MakeThumbnailImage(string fileName, int width, int height, string mode, out Bitmap bmp, out ImageFormat type)
{
Image originalImage = Image.FromFile(fileName);
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case "HW":
case "WH"://指定高寬縮放
float s = (float)width / (float)height;
float os = (float)ow / (float)oh;
if (s > os)
{
toheight = height;
towidth =(int)( toheight * os);
}
else
{
towidth = width;
toheight =(int)( towidth / os);
}
break;
case "W"://指定寬,高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case "H"://指定高,寬按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case "Cut"://指定高寬裁減(不變形)
if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
{
oh = originalImage.Height;
ow = originalImage.Height * towidth / toheight;
y = 0;
x = (originalImage.Width - ow) / 2;
}
else
{
ow = originalImage.Width;
oh = originalImage.Width * height / towidth;
x = 0;
y = (originalImage.Height - oh) / 2;
}
break;
default:
break;
}
//新建一個bmp圖片
Bitmap b = new Bitmap(towidth, toheight);
try
{
//新建一個畫板
Graphics g = Graphics.FromImage(b);
//設置高質量插值法
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
//設置高質量,低速度呈現平滑程度
g.SmoothingMode = SmoothingMode.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
//清空畫布並以透明背景色填充
g.Clear(Color.Transparent);
//在指定位置並且按指定大小繪製原圖片的指定部分
g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel);
bmp = b;
type = GetFormat(fileName);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
}
}
#endregion
#region 2012-10-30 新增圖片裁剪方法
/// <summary>
/// 裁剪圖片並保存
/// </summary>
/// <param name="fileName">源圖路徑(絕對路徑)</param>
/// <param name="newFileName">縮略圖路徑(絕對路徑)</param>
/// <param name="maxWidth">縮略圖寬度</param>
/// <param name="maxHeight">縮略圖高度</param>
/// <param name="cropWidth">裁剪寬度</param>
/// <param name="cropHeight">裁剪高度</param>
/// <param name="X">X軸</param>
/// <param name="Y">Y軸</param>
public static bool MakeThumbnailImage(string fileName, string newFileName, int maxWidth, int maxHeight, int cropWidth, int cropHeight, int X, int Y)
{
byte[] imageBytes = File.ReadAllBytes(fileName);
Image originalImage = Image.FromStream(new System.IO.MemoryStream(imageBytes));
Bitmap b = new Bitmap(cropWidth, cropHeight);
try
{
using (Graphics g = Graphics.FromImage(b))
{
//設置高質量插值法
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
//設置高質量,低速度呈現平滑程度
g.SmoothingMode = SmoothingMode.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
//清空畫布並以透明背景色填充
g.Clear(Color.Transparent);
//在指定位置並且按指定大小繪製原圖片的指定部分
g.DrawImage(originalImage, new Rectangle(0, 0, cropWidth, cropHeight), X, Y, cropWidth, cropHeight, GraphicsUnit.Pixel);
Image displayImage = new Bitmap(b, maxWidth, maxHeight);
SaveImage(displayImage, newFileName, GetCodecInfo("image/" + GetFormat(newFileName).ToString().ToLower()));
return true;
}
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
b.Dispose();
}
}
#endregion
/// <summary>
/// 製作遠程縮略圖
/// </summary>
/// <param name="url">圖片URL</param>
/// <param name="newFileName">新圖路徑</param>
/// <param name="maxWidth">最大寬度</param>
/// <param name="maxHeight">最大高度</param>
public static void MakeRemoteThumbnailImage(string url, string newFileName, int maxWidth, int maxHeight)
{
Stream stream = GetRemoteImage(url);
if(stream == null)
return;
Image original = Image.FromStream(stream);
stream.Close();
MakeThumbnailImage(original, newFileName, maxWidth, maxHeight);
}
/// <summary>
/// 獲取圖片流
/// </summary>
/// <param name="url">圖片URL</param>
/// <returns></returns>
private static Stream GetRemoteImage(string url)
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.Method = "GET";
request.ContentLength = 0;
request.Timeout = 20000;
HttpWebResponse response = null;
try
{
response = (HttpWebResponse)request.GetResponse();
return response.GetResponseStream();
}
catch
{
return null;
}
}
}
}