How Can I Capture a Windows Application Screenshot Using the Win32 API?

Windows Application Screenshot Capture

In Windows programming, capturing a screenshot of the current screen is a common requirement. For this purpose, the Win32 API provides the necessary functions to acquire a bitmap representation of the screen.

Win32 Screenshot Code

To take a screenshot in a Windows application using Win32, follow these steps:

HDC hScreenDC = GetDC(nullptr);

Retrieve the device context of the entire screen.

HDC hMemoryDC = CreateCompatibleDC(hScreenDC);

Create a compatible device context for copying the screen bitmap.

int width = GetDeviceCaps(hScreenDC,HORZRES);
int height = GetDeviceCaps(hScreenDC,VERTRES);

Obtain the width and height of the screen in pixels.

HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC,width,height);

Create a compatible bitmap to hold the screen image.

HBITMAP hOldBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC,hBitmap));

Select the compatible bitmap into the compatible device context.

BitBlt(hMemoryDC,0,0,width,height,hScreenDC,0,0,SRCCOPY);

Copy the screen image to the compatible bitmap using bit block transfer (BitBlt).

hBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC,hOldBitmap));

Restore the previous bitmap selection to the memory device context.

DeleteDC(hMemoryDC);
DeleteDC(hScreenDC);

Delete both device contexts to release resources.

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