How to resize image with different resolution

Question

I have to display image in photo gallery @ width=200 height=180, but while uploading images I have to resize it , but the problem is every image have different resolution. How can I resize the images with different resolution so that images remain intact. Here is my code :

private void ResizeImage()
{
    System.Drawing.Image ImageToUpload = System.Drawing.Image.FromStream(FileUpload1.PostedFile.InputStream);
    byte[] image = null;
    int h = ImageToUpload.Height;
    int w = ImageToUpload.Width;
    int r = int.Parse(ImageToUpload.VerticalResolution.ToString());
    int NewWidth = 200;//constant
    int NewHeight = 180;//constant
    byte[] imagesize = FileUpload1.FileBytes;
    System.Drawing.Bitmap BitMapImage = new System.Drawing.Bitmap(ImageToUpload, NewWidth, NewHeight);//this line gives horrible output
    MemoryStream Memory = new MemoryStream();
    BitMapImage.Save(Memory, System.Drawing.Imaging.ImageFormat.Jpeg);
    Memory.Position = 0;
    image = new byte[Memory.Length + 1];
    Memory.Read(image, 0, image.Length);
}

if resolution is 96 and if I set maxwidth=200 then its height would be 150 then only the image looks small and accurate. Can't we resize image in desired way so that it looks exact?

Satpal · Accepted Answer · 2020-11-15 14:40:16Z

2

The function will resize the image maintaining aspect ratio.

public static Image Resize(Image originalImage, int w, int h)
{
    //Original Image attributes
    int originalWidth = originalImage.Width;
    int originalHeight = originalImage.Height;

    // Figure out the ratio
    double ratioX = (double)w / (double)originalWidth;
    double ratioY = (double)h / (double)originalHeight;
    // use whichever multiplier is smaller
    double ratio = ratioX < ratioY ? ratioX : ratioY;

    // now we can get the new height and width
    int newHeight = Convert.ToInt32(originalHeight * ratio);
    int newWidth = Convert.ToInt32(originalWidth * ratio);

    Image thumbnail = new Bitmap(newWidth, newHeight);
    Graphics graphic = Graphics.FromImage(thumbnail);

    graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
    graphic.SmoothingMode = SmoothingMode.HighQuality;
    graphic.PixelOffsetMode = PixelOffsetMode.HighQuality;
    graphic.CompositingQuality = CompositingQuality.HighQuality;

    graphic.Clear(Color.Transparent);
    graphic.DrawImage(originalImage, 0, 0, newWidth, newHeight);

    return thumbnail;
}

Usage

Image BitMapImage = Resize(ImageToUpload, NewWidth, NewHeight);

edited Nov 15, 2020 at 14:40

answered Jul 3, 2013 at 6:31

Satpal

134k13 gold badges168 silver badges171 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Dee.Pee.Gurung Over a year ago

Thank you once again, would you tell me how to cover the blank space? You might not understand my question. As I said I have fixed the height and width 200x150, your code is perfect, but here I will give an example if I upload a image having resolution=150 then the new width and height would be 105x150 that means there would 95px blank in either side of width. How can I fill that portion?

Bikuz · Accepted Answer · 2018-03-05 05:51:50Z

Here i keep height fixed to 180 to maintain aspect ratio. It will resize the image and save to disk. The return value is the percentage value which i use in 'background-size' css.

public float ResizePhoto(string filepath, string filename)
    {
        var path = Path.Combine(filepath, filename);
        var newPath = Path.Combine(filepath, "sml_" + filename);
        Image orgImage = Image.FromFile(path);

        float fixedHt = 180f;
        int destHeight, destWidth;
        float reqScale;


        if(orgImage.Height > fixedHt)
        {
            destHeight = (int)fixedHt;
            destWidth = (int)(fixedHt / orgImage.Height * orgImage.Width);
            reqScale = destWidth  / destHeight * 100;
        }
        else
        {
            destHeight = orgImage.Height;
            destWidth = orgImage.Width;
            reqScale = fixedHt / destHeight * 100;
        }

        Bitmap bmp = new Bitmap(destWidth, destHeight);
        bmp.SetResolution(orgImage.HorizontalResolution,orgImage.VerticalResolution);
        Graphics grPhoto = Graphics.FromImage(bmp);

        grPhoto.DrawImage(orgImage,
            new Rectangle(0, 0, destWidth,  destHeight),
            new Rectangle(0, 0, orgImage.Width, orgImage.Height),
            GraphicsUnit.Pixel);

        bmp.Save(newPath);

        return reqScale;
    }

Collectives™ on Stack Overflow

How to resize image with different resolution

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related