.net如何上传图片,并生成缩略图效果
.net如何上传图片,并生成缩略图效果
2011年04月18日
很晚了。就不和大家废话了。搞了一晚才搞定。和大家分享一下啊:
请看代码:
protected void btnUpLoad_Click(object sender, EventArgs e)
{
//判断是否有文件提交
if (HttpContext.Current.Request.Files.Count != 0)
{
string path = HttpContext.Current.Request.ApplicationPath;
HttpPostedFile postFile = HttpContext.Current.Request.Files[0];
string filename = DateTime.Now.Second.ToString() + DateTime.Now.Millisecond.ToString();
SavePostedImage(postFile, path + "/UploadImg/", filename, 100, 100, System.Drawing.Imaging.ImageFormat.Jpeg, 0.8);
filename += "-isBig";
SavePostedImage(postFile, path + "/UploadImg/", filename, 502, 670, System.Drawing.Imaging.ImageFormat.Jpeg, 0.8);
postFile.InputStream.Close();
}
}
///
/// 上传图片 集成cmyk→rgb
///
/// 上载文件的访问
/// 保存目录
/// 新名字
/// 限高
/// 限宽
/// 图片格式要求
/// 压缩比(double:0--1)
/// 上传后的文件名
public string SavePostedImage(HttpPostedFile postedFile, string filePath, string fileName, int maxHeight, int maxWidth, System.Drawing.Imaging.ImageFormat imgFormat, double rate)
{
try
{
//判断压缩格式
if (imgFormat == null)
{
if (postedFile.FileName.ToLower().EndsWith("jpg"))
{
imgFormat = ImageFormat.Jpeg;
}
else if (postedFile.FileName.ToLower().EndsWith("gif"))
{
imgFormat = ImageFormat.Gif;
}
else if (postedFile.FileName.ToLower().EndsWith("bmp"))
{
imgFormat = ImageFormat.Bmp;
}
else if (postedFile.FileName.ToLower().EndsWith("png"))
{
imgFormat = ImageFormat.Png;
}
else if (postedFile.FileName.ToLower().EndsWith("tiff"))
{
imgFormat = ImageFormat.Tiff;
}
else if (postedFile.FileName.ToLower().EndsWith("icon"))
{
imgFormat = ImageFormat.Icon;
}
else
{
return "";
}
}
Bitmap bmp = new Bitmap(postedFile.InputStream);
bmp = IsCMYK(bmp) ? ConvertCMYK(bmp, rate) : bmp;
if ((bmp.HorizontalResolution > 72) || (bmp.VerticalResolution > 72))
{
bmp.SetResolution(72, 72);
}
Bitmap saveBmp;
//判断大小,进行压缩
if (bmp.Height > maxHeight)
{
if ((maxHeight == 0) || (maxWidth == 0))
{
saveBmp = new Bitmap(bmp);
}
else
{
Double heightRatio = Convert.ToDouble(maxHeight) / Convert.ToDouble(bmp.Height);
Double widthRatio = Convert.ToDouble(maxWidth) / Convert.ToDouble(bmp.Width);
Double scaleRatio;
scaleRatio = heightRatio > widthRatio ? widthRatio : heightRatio;
saveBmp = new Bitmap(bmp, Convert.ToInt32(bmp.Width * scaleRatio), Convert.ToInt32(bmp.Height * scaleRatio));
while (Convert.ToInt32(saveBmp.Height * scaleRatio) > maxHeight)
{
heightRatio = Convert.ToDouble(maxHeight) / Convert.ToDouble(bmp.Height);
widthRatio = Convert.ToDouble(maxWidth) / Convert.ToDouble(bmp.Width);
scaleRatio = heightRatio > widthRatio ? widthRatio : heightRatio;
saveBmp = new Bitmap(bmp, Convert.ToInt32(bmp.Width * scaleRatio), Convert.ToInt32(bmp.Height * scaleRatio));
}
}
}
else
{
saveBmp = new Bitmap(bmp);
}
DateTime DateFile = DateTime.Now;
string NewFileName = DateFile.Year.ToString() + DateFile.Month.ToString()+DateFile.Day.ToString() + DateFile.Hour.ToString() + DateFile.Minute.ToString();
fileName = fileName.LastIndexOf('.') > 0 ? fileName.Substring(0, fileName.IndexOf('.')) : fileName.Replace(".", "");
fileName = fileName != "" ? NewFileName + fileName : NewFileName;
string path = HttpContext.Current.Server.MapPath(filePath);
//如果不存在该文件夹
if (!Directory.Exists(path))
Directory.CreateDirectory(path);
fileName += "." + imgFormat.ToString();
saveBmp.Save(path + "\\" + fileName, imgFormat);
bmp.Dispose();
saveBmp.Dispose();
}
catch (System.Exception)
{
fileName = "";
}
return fileName;
}
private bool IsCMYK(System.Drawing.Image img)
{
string FlagVals = GetImageFlags(img);
if ((FlagVals.IndexOf("Ycck") > -1) || (FlagVals.IndexOf("Cmyk") > -1))
{ return true; }
else
{ return false; }
}
private string GetImageFlags(System.Drawing.Image img)
{
ImageFlags FlagVals = (ImageFlags)Enum.Parse(typeof(ImageFlags), img.Flags.ToString());
return FlagVals.ToString();
}
private Bitmap ConvertCMYK(Bitmap bmp, double rate)
{
rate = rate > 1.0 ? 1.0 : rate;
rate = rate RGB了
g.DrawImage(bmp, rect);
Bitmap returnBmp = new Bitmap(tmpBmp);
g.Dispose();
tmpBmp.Dispose();
bmp.Dispose();
return returnBmp;
}
搞定收工。洗澡睡觉!
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转载自ors501ln.iteye.com/blog/1357734
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