Can I select a font into a DC from GetDC(NULL)?

2
votes

What is the difference between GetDC(hwnd) and GetDC(NULL)? I understand that the latter gets a DC for the entire (virtual) screen, but I'm not sure what that means practically.

I want to set the size of an initial window based on the font in use. I use CreateFontIndirect to create the font handle but, in my opinion, only when you SelectObject that font into a DC can you use GetTextMetrics to figure out the actual height used rather than one specified. I'm going on the assumption that they may not be the same.

I would normally use GetDC(hwnd) to get a DC and select the font into it. But, given I don't have a hwnd yet, can I select a font into a DC returned from GetDC(NULL)?

Edit: Related. I guess it may make no difference! GetDC(NULL) gets primary monitor or virtual screen?

1
windowswinapi

1 Answers

4
votes

You don't own the screen DC and should not select objects into it. What you can do is use CreateCompatibleDC, passing the screen DC, to get a DC into which you can perform text metrics calculations.