Saving as jpeg from memorystream in c#

倖福魔咒の 提交于 2019-12-01 09:02:08

Resize the Image and Save it

Private void ResizeImage(Image img, double maxWidth, double maxHeight)
{
    double srcWidth = img.Source.Width;
    double srcHeight = img.Source.Height;

    double resizeWidth = srcWidth;
    double resizeHeight = srcHeight;

    double aspect = resizeWidth / resizeHeight;

    if (resizeWidth > maxWidth)
    {
        resizeWidth = maxWidth;
        resizeHeight = resizeWidth / aspect;
    }
    if (resizeHeight > maxHeight)
    {
        aspect = resizeWidth / resizeHeight;
        resizeHeight = maxHeight;
        resizeWidth = resizeHeight * aspect;
    }

    img.Width = resizeWidth;
    img.Height = resizeHeight;
}

You could use this code to Resize the image to the required Dimention Before saving it

As others have mentioned, if you want all images to be the same size without distortion, you're going to need to resize while maintaining the aspect ratio. See this function below:

public Image ResizeWithSameRatio(Image image, float width, float height)
{
    // the colour for letter boxing, can be a parameter
    var brush = new SolidBrush(Color.Black);

    // target scaling factor
    float scale = Math.Min(width / image.Width, height / image.Height);

    // target image
    var bmp = new Bitmap((int)width, (int)height);
    var graph = Graphics.FromImage(bmp);

    var scaleWidth = (int)(image.Width * scale);
    var scaleHeight = (int)(image.Height * scale);

    // fill the background and then draw the image in the 'centre'
    graph.FillRectangle(brush, new RectangleF(0, 0, width, height));
    graph.DrawImage(image, new Rectangle(((int)width - scaleWidth)/2, ((int)height - scaleHeight)/2, scaleWidth, scaleHeight));

    return bmp;
}

Now your usage function can be significantly simplified (assuming 1024x768 target images here):

public void SaveFileOnDisk(MemoryStream ms, string FileName)
{
    try
    {
        string appPath = HttpContext.Current.Request.ApplicationPath;
        string physicalPath = HttpContext.Current.Request.MapPath(appPath);
        string strpath = physicalPath + "\\Images";
        string WorkingDirectory = strpath;

        using (var original = Image.FromStream(ms))
        using (var resized = ResizeWithSameRatio(original, 1024, 768))
        {
            resized.Save(WorkingDirectory + "\\" + FileName + ".jpg");
        }
    }
    catch (Exception ex)
    {
        //lblMsg.Text = "Please try again later.";
    }
}

Note the added simplification in terms of number of variables, and disposing by using using instead of Dispose().

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