BitBlt Inconsistent Behavior for Capturing Desktop When No Monitor is Connected

[gasperl]

Hello,

I'm encountering an issue when trying to capture the entire desktop using BitBlt on systems where no monitor is connected. The situation is as follows:

• Setup: I'm capturing the desktop by calling GetDC(NULL) to get the desktop device context and then using BitBlt to copy the screen content into a bitmap.
• Issue: When no monitor is connected, BitBlt sometimes fails to update the entire screen content correctly in the bitmap. Portions of the captured image appear to be outdated or incomplete.
• Problematic Windows: The issue seems to be particularly problematic with DirectX windows that have the WS_EX_NOREDIRECTIONBITMAP flag set.
• Alternative Attempt: I've also tried using PrintWindow, which does update the bitmap correctly, but it seems unsuitable for my needs since it doesn't capture the entire desktop composition (i.e., it doesn't account for layered windows, transparency, etc.).

Could this be related to how the Intel graphics driver handles desktop composition or display output when no monitor is connected, especially for DirectX windows with the WS_EX_NOREDIRECTIONBITMAP flag? Is there a more reliable method for capturing the entire desktop in such a scenario?

Any insights or suggestions would be greatly appreciated.

Thank you!

[DhannielM_Intel]

Hi gasperl,

Thank you for posting to the community,

I would like to ask you some clarification for me to fully understand your situation. Please share some information by answering the questions below.

1. Is your system a desktop or laptop? If desktop, can you share to me the model of your dedicated GPU?
2. When you say that no monitor is connected, does this mean there is no external monitor connected to your system?
3. Besides using PrintWindow, have you tried updating your graphics driver?

Best regards,

Dhanniel M.

Intel Customer Support Technician

[DhannielM_Intel]

Hi gasperl,

I wanted to check if you had the chance to review the questions I posted. Please let me know at your earliest convenience so that we can determine the best course of action to resolve this matter. 

Best regards,

Dhanniel M.

Intel Customer Support Technician

[DhannielM_Intel]

Hi gasperl,

Since I haven't heard back from you, I will be closing this thread. Though if you have other inquiries or further assistance, please submit a new post as this thread will no longer be monitored.

Best regards,

Dhanniel M.

Intel Customer Support Technician