C# - Capture screenshot of active window

Question

I am making a screen capturing application and everything is going fine. All I need to do is capture the active window and take a screenshot of this active window. Does anyone know how I can do this?

Answer 1

Rectangle bounds = Screen.GetBounds(Point.Empty);
using(Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height))
{
    using(Graphics g = Graphics.FromImage(bitmap))
    {
         g.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size);
    }
    bitmap.Save("test.jpg", ImageFormat.Jpeg);
}

for capturing current window use

 Rectangle bounds = this.Bounds;
 using (Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height))
 {
    using (Graphics g = Graphics.FromImage(bitmap))
    {
        g.CopyFromScreen(new Point(bounds.Left,bounds.Top), Point.Empty, bounds.Size);
    }
    bitmap.Save("C://test.jpg", ImageFormat.Jpeg);
 }

Answer 2

You can use the code from this question: http://stackoverflow.com/questions/158151/how-can-i-save-screenshot-directly-to-a-file-in-windows

Just change WIN32_API.GetDesktopWindow() to the Handle property of the window you want to capture.

Answer 3

ScreenCapture sc = new ScreenCapture();
// capture entire screen, and save it to a file
Image img = sc.CaptureScreen();
// display image in a Picture control named imageDisplay
this.imageDisplay.Image = img;
// capture this window, and save it
sc.CaptureWindowToFile(this.Handle,"C:\\temp2.gif",ImageFormat.Gif);

http://www.developerfusion.com/code/4630/capture-a-screen-shot/

Answer 4

I assume you use Graphics.CopyFromScreen to get the screenshot.

You can use P/Invoke to GetForegroundWindow (and then get its position and size) to determine which region you need to copy from.