How to cut picture from pictureBox by rectangle on it

Question

I need to cut part of picture from pictureBox using rectangle which i have in this picturebox. For now i load image to picture box (and zoom it to picturebox) and draw resizable rectangle inside picturebox, but i don't know how to cut for example left down corner of picturebox by this rectangle.

EDIT

Example I need cut wheel by this rectangle and save it to jpeg but this rectangle is not static.

Answer 1

I'm not entirely sure I understand your full requirement, but you can use BitMap's Clone method to crop an image. For example, this crops an image in one pictureBox1 and loads it into pictureBox2:

using (Bitmap bmp = new Bitmap(pictureBox1.Image))
{
    var newImg = bmp.Clone(
        new Rectangle { X = 10, Y = 10, Width = bmp.Width / 2, Height = bmp.Height / 2 }, 
        bmp.PixelFormat);
    pictureBox2.Image = newImg;
}

It is very easy to leak Handles when manipulating images. You will need to be careful to dispose of pictureBox2.Image later, especially if you're reloading the image multiple times.

Answer 2

Asumming you can create your rectangle and deal with it (drawing it on your picture box, calculating its area...):

    private static Image CropImage(Image img, Rectangle cropArea)
    {
        try {
            Bitmap bmpImage = new Bitmap(img);
            Bitmap bmpCrop = bmpImage.Clone(cropArea /*your rectangle area*/, bmpImage.PixelFormat);
            return (Image)(bmpCrop);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, "CropImage()");
        }
        return null;
    }

    private void saveJpeg(string path, Bitmap img, long quality)
    {
        EncoderParameter qualityParam = new EncoderParameter(
                System.Drawing.Imaging.Encoder.Quality, (long)quality);

        ImageCodecInfo jpegCodec = getEncoderInfo("image/jpeg");

        if (jpegCodec == null)
        {
            MessageBox.Show("Can't find JPEG encoder?", "saveJpeg()");
            return;
        }
        EncoderParameters encoderParams = new EncoderParameters(1);
        encoderParams.Param[0] = qualityParam;

        img.Save(path, jpegCodec, encoderParams);
    }

    private ImageCodecInfo getEncoderInfo(string mimeType)
    {
        ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

        for (int i = 0; i < codecs.Length; i++)
            if (codecs[i].MimeType == mimeType)
                return codecs[i];

        return null;
    }

    private void btnPerformSaveImage_Click(object sender, EventArgs e)
    {
        try
        {
            Image img = (Bitmap)CropImage(new Bitmap(pictureBox1.Image, pictureBox1.Size), CropRect);
            this.DialogResult = System.Windows.Forms.DialogResult.OK;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, "btnOK_Click()");
        }
    }