一个上传图片改变图片大小问题!

Question

我用了FileUpload1来做上传,我现在想在上传图片的时候我能够把图片变小以后在上传,该如何实现,麻烦告知谢谢!我用的是C#语言,麻烦给个完整的例子谢谢!

Answer 1

use the f*cking google!

Answer 2

我这里有个创建缩略图的例子，楼主看下能用不
http://blog.csdn.net/durongjian/archive/2009/05/14/4183109.aspx

Answer 3

上传后再改变大小，
//  保存图片，必要时还要缩小
            if (this.File1.PostedFile.ContentType.IndexOf("image") == -1)
            {                CCClient.AlertMessage("只能上传图片文件！");
                return;
            }
            System.Drawing.Image img = System.Drawing.Image.FromStream(this.File1.PostedFile.InputStream);
            int iMaxWidth = 240;
            int iMaxHeight = 320;            int iNewWidth = 0;
            int iNewHeight = 0;
            if (img.Width > iMaxWidth || img.Height > iMaxHeight)
            {
                iNewWidth = iMaxHeight * img.Width / img.Height;
                iNewHeight = iMaxWidth * img.Height / img.Width;
                if (iNewWidth > iMaxWidth) 还是宽了，以宽为标准计算
                {
                    iNewWidth = iMaxWidth;                }
                else if (iNewHeight > iMaxHeight)
                {
                    iNewHeight = iMaxHeight;
                }                img  = img.GetThumbnailImage(iNewWidth, iNewHeight, null, IntPtr.Zero);
                System.Drawing.Imaging.ImageCodecInfo e = null;
                System.Drawing.Imaging.ImageCodecInfo[] es = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();
               // 扩展名;
               string ext = this.File1.PostedFile.ContentType.ToLower();
               if (ext.IndexOf("gif") > -1)
               {
                   ext = "gif";
               }
               else
               {
                   ext = "jpeg";
               }
                foreach (System.Drawing.Imaging.ImageCodecInfo ef in es)
                {
                  
                    if (ef.MimeType.ToLower().IndexOf(ext) > -1)
                    {
                        e = ef;
                    }
                }
                System.Drawing.Imaging.EncoderParameters ps = new System.Drawing.Imaging.EncoderParameters();
                ps.Param[0] = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)100);                img.Save(NewPath, e, ps);
            }
            else
            {
                this.File1.PostedFile.SaveAs(NewPath);
            }
 

Answer 4

http://blog.csdn.net/slimboy123/archive/2007/08/11/1738217.aspx这里有源码

Answer 5

GetThumbnailImage的效果并不是很好，所以要改成这种方法。    System.Drawing.Bitmap objNewBitMap = new Bitmap(iNewWidth, iNewHeight, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
                      
                        Graphics objGraphics = Graphics.FromImage(objNewBitMap);
                        
                        objGraphics.Clear(Color.Transparent);
                       
                        objGraphics.DrawImage(img, new Rectangle(0, 0, iNewWidth, iNewHeight));
                        objNewBitMap.Save(NewPath, e, ps);