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C# Image Resizing Code to explain

Posted on 2006-10-23
Medium Priority
Last Modified: 2008-01-09
I was given this code to try out for resizing images.

can someone tell me how to call this. I know it is a newbE question but I believe I can just type
ResizeFromByteArray("c:\\img\\filename.jpg", "500",Byte[] byteArrayIn);

but I have no idea what I put in for the
Byte[] byteArrayIn
part of the code does any one here know?

 public static byte[] ResizeFromByteArray(string fileName, int MaxSideSize, Byte[] byteArrayIn)
            byte[] byteArray = null;  // really make this an error gif
            MemoryStream ms = new MemoryStream(byteArrayIn);
            byteArray = CodeCampSV.Utils.ResizeFromStream(fileName, MaxSideSize, ms);

            return byteArray;

        /// <summary>
        /// converts from input stream to output bytearray
        /// inspired from: http://www.eggheadcafe.com/articles/20030515.asp
        /// </summary>
        /// <param name="ImageSavePath"></param>
        /// <param name="MaxSideSize"></param>
        /// <param name="Buffer"></param>
        /// <returns></returns>
        public static byte[] ResizeFromStream(string fileName, int MaxSideSize, Stream Buffer)
            byte[] byteArray = null;  // really make this an error gif



                Bitmap bitMap = new Bitmap(Buffer);
                int intOldWidth = bitMap.Width;
                int intOldHeight = bitMap.Height;

                int intNewWidth;
                int intNewHeight;

                int intMaxSide;

                if (intOldWidth >= intOldHeight)
                    intMaxSide = intOldWidth;
                    intMaxSide = intOldHeight;

                if (intMaxSide > MaxSideSize)
                    //set new width and height
                    double dblCoef = MaxSideSize / (double)intMaxSide;
                    intNewWidth = Convert.ToInt32(dblCoef * intOldWidth);
                    intNewHeight = Convert.ToInt32(dblCoef * intOldHeight);
                    intNewWidth = intOldWidth;
                    intNewHeight = intOldHeight;

                Size ThumbNailSize = new Size(intNewWidth, intNewHeight);
                System.Drawing.Image oImg = System.Drawing.Image.FromStream(Buffer);
                System.Drawing.Image oThumbNail = new Bitmap
                    (ThumbNailSize.Width, ThumbNailSize.Height);
                Graphics oGraphic = Graphics.FromImage(oThumbNail);
                oGraphic.CompositingQuality = CompositingQuality.HighQuality;
                oGraphic.SmoothingMode = SmoothingMode.HighQuality;
                oGraphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
                Rectangle oRectangle = new Rectangle
                    (0, 0, ThumbNailSize.Width, ThumbNailSize.Height);

                oGraphic.DrawImage(oImg, oRectangle);

                //string fileName = Context.Server.MapPath("~/App_Data/") + "test1.jpg";
                //oThumbNail.Save(fileName, ImageFormat.Jpeg);
                MemoryStream ms = new MemoryStream();
                oThumbNail.Save(ms, ImageFormat.Jpeg);
                byteArray = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(byteArray, 0, Convert.ToInt32(ms.Length));

            catch (Exception)
                int newSize = MaxSideSize - 20;
                Bitmap bitMap = new Bitmap(newSize, newSize);
                Graphics g = Graphics.FromImage(bitMap);
                g.FillRectangle(new SolidBrush(Color.Gray), new Rectangle(0, 0, newSize, newSize));

                Font font = new Font("Courier", 8);
                SolidBrush solidBrush = new SolidBrush(Color.Red);
                g.DrawString("Failed File", font, solidBrush, 10, 5);
                g.DrawString(fileName, font, solidBrush, 10, 50);

                MemoryStream ms = new MemoryStream();
                bitMap.Save(ms, ImageFormat.Jpeg);
                byteArray = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(byteArray, 0, Convert.ToInt32(ms.Length));


            return byteArray;

Question by:Scripter25
LVL 11

Expert Comment

by:Ramesh Srinivas
ID: 17794270

I believe that this code is to convert an image into a bytearray for transport through a webservice.

If you just want to resize an image then you can use the following code:


Alternatively, do a search for "ASP.NET Resize image" and you will find many examples.



LVL 21

Accepted Solution

MogalManic earned 2000 total points
ID: 17794868
You can also call ResizeFromStream() method if that is easier.  Given a filename, here is how you would call ResizeFromStream
   string fileName=base.MapPath("~/images/largePhoto.jpg";
   FileStream inFile=System.IO.File.Open (fileName, FileMode.Open);

   byte[] results = CodeCampSV.Utils.ResizeFromStream(base.MapPath("~/images/SmallPhoto.jpg", 10, inFile);

You would call the other method if you already had the image in memory (i.e. you just created it).  If you called the ResizeFromByteArray() method for a file, first you would have to read the file into a byte array, then the function would just convert the byte array  into a Stream and call ResizeFromStream().  So in your process would then have the file in memory at least twice (once in the byte array & once in the memory stream).

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