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Printscreen mechanism

Posted: Tue Jul 28, 2009 3:42 am
by dejvos
Hello,

I wondering to know how the mechanism of printscreen works. Is screen readed from a buffer of a graphic card or another memory?
Can I discover this way, if the graphic card is OK? Or is another way? ( I can't see a screen )

Thanks!

Re: Printscreen mechanism

Posted: Tue Jul 28, 2009 5:59 am
by jackpf
I had a google, but I just found a bunch of idiots asking "Why doesn't print screen print the screen from my printer?"...fools.

But I don't know. I'd imagine it copies the screen buffer from ram or something. Although I could be completely wrong :dubious: so don't take my word for it....

Re: Printscreen mechanism

Posted: Tue Jul 28, 2009 5:44 pm
by Weirdan
I guess it's copied from offscreen buffer. See this source for example: https://www.atmos.washington.edu/svn/iv ... dow_Dump.c

Re: Printscreen mechanism

Posted: Wed Jul 29, 2009 5:30 am
by dejvos
So it's look like that a printing screen is independent on functionality of a graphic card. Because printscreen reads buffer (object) in primary memroy (if I understand to malloc() well).

Is there any command, which I can use to explore if the graphic card on remote machine works correctly?