Question

My app make screenshot using methods from WinAPI. Screen is ok, it is saved as gif and has 76 kB. Jpg, png and other formats have more size. I have to send this file via net and it takes several seconds, about 2-3 seconds. It is posibility to compress this file in .NET or any free external software ? Quality don’t have good, because I have to read only several labels.

Thanks

Answer 1

You could look at resizing the image in c#. It’s fairly easy to do… here’s some code I’ve used in the past to do this:

Image image = Image.FromFile(fi.FullName);
image = resizeImage(image, new Size(120, 120));
EncoderParameter qualityParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)85);
ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");
EncoderParameters encoderParams = new EncoderParameters(1);
encoderParams.Param[0] = qualityParam;
image.Save(OutSourceLoc + "/" + fi.Name, jpegCodec, encoderParams);


static Image resizeImage(Image imgToResize, Size size)
    {
        int sourceWidth = imgToResize.Width;
        int sourceHeight = imgToResize.Height;

        float nPercent = 0;
        float nPercentW = 0;
        float nPercentH = 0;

        nPercentW = ((float)size.Width / (float)sourceWidth);
        nPercentH = ((float)size.Height / (float)sourceHeight);

        if (nPercentH < nPercentW)
            nPercent = nPercentH;
        else
            nPercent = nPercentW;

        int destWidth = (int)(sourceWidth * nPercent);
        int destHeight = (int)(sourceHeight * nPercent);

        Bitmap b = new Bitmap(destWidth, destHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
        b.SetResolution(300, 300);
        Graphics g = Graphics.FromImage((Image)b);
        g.InterpolationMode = InterpolationMode.HighQualityBicubic;
        g.CompositingQuality = CompositingQuality.HighSpeed;
        g.SmoothingMode = SmoothingMode.HighSpeed;

        g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
        g.Dispose();

        return (Image)b;

    }

    private static ImageCodecInfo GetEncoderInfo(string mimeType)
    {
        // Get image codecs for all image formats 
        ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

        // Find the correct image codec 
        for (int i = 0; i < codecs.Length; i++)
            if (codecs[i].MimeType == mimeType)
                return codecs[i];
        return null;
    }