/// <summary> /// Get the color from the pixel on the screen at "x,y" /// </summary> /// <param name="screenCoordinates">Point with the coordinates</param> /// <returns>Color at the specified screenCoordinates</returns> private static Color GetPixelColor(Point screenCoordinates) { using (SafeWindowDCHandle screenDC = SafeWindowDCHandle.FromDesktop()) { try { uint pixel = GDI32.GetPixel(screenDC, screenCoordinates.X, screenCoordinates.Y); Color color = Color.FromArgb(255, (int)(pixel & 0xFF), (int)(pixel & 0xFF00) >> 8, (int)(pixel & 0xFF0000) >> 16); return(color); } catch (Exception) { return(Color.Empty); } } }
/// <summary> /// This method will use User32 code to capture the specified captureBounds from the screen /// </summary> /// <param name="captureBounds">Rectangle with the bounds to capture</param> /// <returns>Bitmap which is captured from the screen at the location specified by the captureBounds</returns> public static Bitmap CaptureRectangle(Rectangle captureBounds) { Bitmap returnBitmap = null; if (captureBounds.Height <= 0 || captureBounds.Width <= 0) { LOG.Warn("Nothing to capture, ignoring!"); return(null); } LOG.Debug("CaptureRectangle Called!"); // .NET GDI+ Solution, according to some post this has a GDI+ leak... // See http://connect.microsoft.com/VisualStudio/feedback/details/344752/gdi-object-leak-when-calling-graphics-copyfromscreen // Bitmap capturedBitmap = new Bitmap(captureBounds.Width, captureBounds.Height); // using (Graphics graphics = Graphics.FromImage(capturedBitmap)) { // graphics.CopyFromScreen(captureBounds.Location, Point.Empty, captureBounds.Size, CopyPixelOperation.CaptureBlt); // } // capture.Image = capturedBitmap; // capture.Location = captureBounds.Location; using (SafeWindowDCHandle desktopDCHandle = SafeWindowDCHandle.FromDesktop()) { if (desktopDCHandle.IsInvalid) { // Get Exception before the error is lost Exception exceptionToThrow = CreateCaptureException("desktopDCHandle", captureBounds); // throw exception throw exceptionToThrow; } // create a device context we can copy to using (SafeCompatibleDCHandle safeCompatibleDCHandle = GDI32.CreateCompatibleDC(desktopDCHandle)) { // Check if the device context is there, if not throw an error with as much info as possible! if (safeCompatibleDCHandle.IsInvalid) { // Get Exception before the error is lost Exception exceptionToThrow = CreateCaptureException("CreateCompatibleDC", captureBounds); // throw exception throw exceptionToThrow; } // Create BITMAPINFOHEADER for CreateDIBSection BITMAPINFOHEADER bmi = new BITMAPINFOHEADER(captureBounds.Width, captureBounds.Height, 24); // Make sure the last error is set to 0 Win32.SetLastError(0); // create a bitmap we can copy it to, using GetDeviceCaps to get the width/height IntPtr bits0; // not used for our purposes. It returns a pointer to the raw bits that make up the bitmap. using (SafeDibSectionHandle safeDibSectionHandle = GDI32.CreateDIBSection(desktopDCHandle, ref bmi, BITMAPINFOHEADER.DIB_RGB_COLORS, out bits0, IntPtr.Zero, 0)) { if (safeDibSectionHandle.IsInvalid) { // Get Exception before the error is lost Exception exceptionToThrow = CreateCaptureException("CreateDIBSection", captureBounds); exceptionToThrow.Data.Add("hdcDest", safeCompatibleDCHandle.DangerousGetHandle().ToInt32()); exceptionToThrow.Data.Add("hdcSrc", desktopDCHandle.DangerousGetHandle().ToInt32()); // Throw so people can report the problem throw exceptionToThrow; } // select the bitmap object and store the old handle using (safeCompatibleDCHandle.SelectObject(safeDibSectionHandle)) { // bitblt over (make copy) GDI32.BitBlt(safeCompatibleDCHandle, 0, 0, captureBounds.Width, captureBounds.Height, desktopDCHandle, captureBounds.X, captureBounds.Y, CopyPixelOperation.SourceCopy | CopyPixelOperation.CaptureBlt); } // get a .NET image object for it // A suggestion for the "A generic error occurred in GDI+." E_FAIL/0×80004005 error is to re-try... bool success = false; ExternalException exception = null; for (int i = 0; i < 3; i++) { try { // Collect all screens inside this capture List <Screen> screensInsideCapture = new List <Screen>(); foreach (Screen screen in Screen.AllScreens) { if (screen.Bounds.IntersectsWith(captureBounds)) { screensInsideCapture.Add(screen); } } // Check all all screens are of an equal size bool offscreenContent; using (Region captureRegion = new Region(captureBounds)) { // Exclude every visible part foreach (Screen screen in screensInsideCapture) { captureRegion.Exclude(screen.Bounds); } // If the region is not empty, we have "offscreenContent" using (Graphics screenGraphics = Graphics.FromHwnd(User32.GetDesktopWindow())) { offscreenContent = !captureRegion.IsEmpty(screenGraphics); } } // Check if we need to have a transparent background, needed for offscreen content if (offscreenContent) { using (Bitmap tmpBitmap = Image.FromHbitmap(safeDibSectionHandle.DangerousGetHandle())) { // Create a new bitmap which has a transparent background returnBitmap = ImageHelper.CreateEmpty(tmpBitmap.Width, tmpBitmap.Height, PixelFormat.Format32bppArgb, Color.Transparent, tmpBitmap.HorizontalResolution, tmpBitmap.VerticalResolution); // Content will be copied here using (Graphics graphics = Graphics.FromImage(returnBitmap)) { // For all screens copy the content to the new bitmap foreach (Screen screen in Screen.AllScreens) { Rectangle screenBounds = screen.Bounds; // Make sure the bounds are offsetted to the capture bounds screenBounds.Offset(-captureBounds.X, -captureBounds.Y); graphics.DrawImage(tmpBitmap, screenBounds, screenBounds.X, screenBounds.Y, screenBounds.Width, screenBounds.Height, GraphicsUnit.Pixel); } } } } else { // All screens, which are inside the capture, are of equal size // assign image to Capture, the image will be disposed there.. returnBitmap = Image.FromHbitmap(safeDibSectionHandle.DangerousGetHandle()); } // We got through the capture without exception success = true; break; } catch (ExternalException ee) { LOG.Warn("Problem getting bitmap at try " + i + " : ", ee); exception = ee; } } if (!success) { LOG.Error("Still couldn't create Bitmap!"); if (exception != null) { throw exception; } } } } } return(returnBitmap); }