//изменение контрастности
        private void trackBar2_Scroll(object sender, EventArgs e)
        {
            if (Form1.full_name_of_image != "\0")
            {
                UInt32 p;
                for (int i = 0; i < Form1.image.Height; i++)
                {
                    for (int j = 0; j < Form1.image.Width; j++)
                    {
                        p = BrightnessContrast.Contrast(Form1.pixel[i, j], trackBar2.Value, trackBar2.Maximum);
                        Form1.FromOnePixelToBitmap(i, j, p);
                    }
                }

                FromBitmapToScreen();
            }
        }