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POPrintWindow bitmap differs from PrintScreen Key bitmap
 

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  1. POPrintWindow bitmap differs from PrintScreen Key bitmap
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    <p>When capturing a window manually with the <code>Print Screen</code>+<code>Alt</code> key combo, I get the following:</p> <p><img src="https://i.stack.imgur.com/aEhHY.png" alt="enter image description here"></p> <p>but if I try to do it programmatically using <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd162869%28v=vs.85%29.aspx" rel="nofollow noreferrer">Windows API</a>, I get this:</p> <p><img src="https://i.stack.imgur.com/VOOjh.png" alt="enter image description here"></p> <p><strong>Why the discrepancy? How do I get the first programmatically?</strong></p> <p>Here is my code:</p> <pre><code> [DllImport("user32.dll")] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool PrintWindow(IntPtr hWnd, IntPtr hdcBlt, int nFlags); public Bitmap PrintWindow() { Bitmap bmp = new Bitmap(windowRect.Width, windowRect.Height, PixelFormat.Format32bppArgb); Graphics gfxBmp = Graphics.FromImage(bmp); IntPtr hdcBitmap = gfxBmp.GetHdc(); bool success = PrintWindow(windowHandle, hdcBitmap, 0); gfxBmp.ReleaseHdc(hdcBitmap); if (!success) { Console.WriteLine("Error copying image"); Console.WriteLine(getLastError()); } gfxBmp.Dispose(); return bmp; } </code></pre> <hr> <p><strong>Update:</strong> Doing it with BitBlt does the same thing.</p> <p>Here's <a href="http://www.codeproject.com/Articles/14656/Sending-Input-Messages-to-Other-Windows-or-How-To" rel="nofollow noreferrer">code from CodeProject</a> that still returns a black-masked image:</p> <pre><code>public Image CaptureWindow(IntPtr handle) { // get te hDC of the target window IntPtr hdcSrc = User32.GetWindowDC(handle); // get the size User32.RECT windowRect = new User32.RECT(); User32.GetWindowRect(handle,ref windowRect); int width = windowRect.right - windowRect.left; int height = windowRect.bottom - windowRect.top; // create a device context we can copy to IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc); // create a bitmap we can copy it to, // using GetDeviceCaps to get the width/height IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc,width,height); // select the bitmap object IntPtr hOld = GDI32.SelectObject(hdcDest,hBitmap); // bitblt over GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, CopyPixelOperation.SourceCopy | CopyPixelOperation.CaptureBlt); // restore selection GDI32.SelectObject(hdcDest,hOld); // clean up GDI32.DeleteDC(hdcDest); User32.ReleaseDC(handle,hdcSrc); // get a .NET image object for it Image img = Image.FromHbitmap(hBitmap); // free up the Bitmap object GDI32.DeleteObject(hBitmap); img.Save("SampleImage.png"); return img; } </code></pre> <p>I have tried many combinations of <code>CopyPixelOperation</code>, (somewhere around 15,000 of the 131,000) but it still doesn't work.</p> <p>Using Windows 8, AMD Radeon HD 6870.</p> <hr> <p><strong>Update 2</strong></p> <p>It seems that the window is transparent, allowing the blue color of the window to bleed through. When I change the window color to black (using the Windows personalization dialog), I get roughly something similar to the second window. The border is still missing though.</p> <p>I haven't found a solution, but it's insight into the problem.</p>
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    1. COWhen you called `PrintWindow()`, how did you manufacture the DC you sent to the API call?
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    2. COWhat do you get if you use `PixelFormat.Format24bppRgb`?
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    3. COI just tried and got the same image, even with PW_CLIENTONLY flag
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