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The Win32 tips and trix

Take a screenshot of any given HWND!

Currently I’m working on a project that uses screenshots, and I just wanted to share this snippet.

// Function created by: Lars Werner - http://lars.werner.no
// Inputs: HWND hParent = the window we want to get DC from, eg
// ::GetDesktopWindow();
// int x = x-position of the screen
// int y = y-position of the screen
// int nWidth = Width of the screenshot
// int nHeight = Height of the screenshot
// Return: HBITMAP = Handle isn't deleted in function, please use
// DeleteObject() when finished with object!
// Version: 1.0 = Inital Release
HBITMAP ScreenShot(HWND hParent, int x, int y, int nWidth, int nHeight)
//Get a DC from the parent window
HDC hDC = GetDC(hParent);

//Create a memory DC to store the picture to
HDC hMemDC = CreateCompatibleDC(hDC);

//Create the actual picture
HBITMAP hBackground = CreateCompatibleBitmap(hDC, nWidth, nHeight );

//Select the object and store what we got back
HBITMAP hOld = (HBITMAP)SelectObject(hMemDC, hBackground);

//Now do the actually painting into the MemDC (result will be in the selected object)
//Note: We ask to return on 0,0,Width,Height and take a blit from x,y
BitBlt(hMemDC, 0, 0, nWidth, nHeight, hDC, x, y, SRCCOPY);

//Restore the old bitmap (if any)
SelectObject(hMemDC, hOld);

//Release the DCs we created
ReleaseDC(hParent, hMemDC);
ReleaseDC(hParent, hDC);

//Return the picture (not a clean method, but you get the drill)
return hBackground;

Any comments, error or bad design, please let me know in the comments!