asp.net改变上传图片的物理大小，能否实现。。

lz00728 2012-11-01 04:53:25

上传图片太大，能否在上传后改变图片的物理大小，不改变图片原来的尺寸，也不很大影响图片的原来画质。
求解...

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uinatlex 2012-11-02

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  /// <summary>

        /// 执行: 压缩原图 System.Drawing.Bitmap 对象保存到文件 (JPEG格式压缩)

        /// </summary>

        /// <param name="source">原图 System.Drawing.Bitmap 对象: System.Drawing.Bitmap</param>

        /// <param name="level">压缩等级(值越高图像质量越好,文件越大,范围在1~100之间): int</param>

        /// <param name="path">保存路径(包含完整路径,文件名及其扩展名): string</param>

        public void Compress(Bitmap source, int level, string path)

        {

            if (level < 1 || level > 99)

                throw new ArgumentException("压缩等级值范围在0~100之间");

            long[] quality = new long[1];

            quality[0] = level;

            using (EncoderParameters Parameters = new EncoderParameters())

            {

                using (EncoderParameter Parameter = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality))

                {

                    Parameters.Param[0] = Parameter;

                    source.Save(path, ImageCodecInfo.GetImageEncoders()[1], Parameters);



                }

            }



        }

遊戲王千金 2012-11-02

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 /// <summary>

        /// 压缩到指定尺寸

        /// </summary>

        /// <param name="oldfile">原文件</param>

        /// <param name="newfile">新文件</param>

        public bool Compress(string oldfile, string newfile)

        {

            try

            {

                System.Drawing.Image img = System.Drawing.Image.FromFile(oldfile);

                System.Drawing.Imaging.ImageFormat thisFormat = img.RawFormat;

                Size newSize = new Size(100, 125);

                Bitmap outBmp = new Bitmap(newSize.Width, newSize.Height);

                Graphics g = Graphics.FromImage(outBmp);

                g.CompositingQuality = CompositingQuality.HighQuality;

                g.SmoothingMode = SmoothingMode.HighQuality;

                g.InterpolationMode = InterpolationMode.HighQualityBicubic;

                g.DrawImage(img, new Rectangle(0, 0, newSize.Width, newSize.Height), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel);

                g.Dispose();

                EncoderParameters encoderParams = new EncoderParameters();

                long[] quality = new long[1];

                quality[0] = 100;

                EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);

                encoderParams.Param[0] = encoderParam;

                ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();

                ImageCodecInfo jpegICI = null;

                for (int x = 0; x < arrayICI.Length; x++)

                    if (arrayICI[x].FormatDescription.Equals("JPEG"))

                    {

                        jpegICI = arrayICI[x]; //设置JPEG编码

                        break;

                    }

                img.Dispose();

                if (jpegICI != null) outBmp.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);

                outBmp.Dispose();

                return true;

            }

            catch

            {

                return false;

            }

        }

你们是不是在找BUG 2012-11-02

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图片压缩，截取等处理

让IE灭亡 2012-11-02

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有，自己去找C# 图片压缩

huxiaoiqing0007 2012-11-01

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给你一段代码吧：
/// <summary>
/// 上传图片生成缩略图
/// </summary>
/// <param name="originalImagePath">源图片</param>
/// <param name="thumbnailPath">缩略图保存路径</param>
/// <param name="width">缩略图宽度</param>
/// <param name="height">缩略图高度</param>
/// <param name="mode">缩略模式</param>
public static void MakeThumbnail(byte [] originalImageByte, string thumbnailPath, int width, int height, string mode)
{
System.IO.Stream imageStream = new System.IO.MemoryStream(originalImageByte);
System.Drawing.Image originalImage = System.Drawing.Image.FromStream(imageStream);

int towidth = width;
int toheight = height;

int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;

switch (mode)
{
case "HW"://指定高宽缩放（可能变形）
break;
case "W"://指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case "H"://指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case "Cut"://指定高宽裁减（不变形）
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;
}
//新建一个bmp图片
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
//新建一个画板
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
//设置高质量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//清空画布并以透明背景色填充
g.Clear(Color.Transparent);
//在指定位置并且按指定大小绘制原图片的指定部分
g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
new Rectangle(x, y, ow, oh),
GraphicsUnit.Pixel);

try
{
//以jpg格式保存缩略图
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
}