[]
Post by j***@astraweb.comThe difference here is that I started using this facility when disk space was still meaningful and
prtscrn gives a .bmp where picasa optioned the screenshot as a .jpg (or .png) -- or probably more to the
point, i come from a time when the "upgrade" hard disk to my 386 was 128 meg instead of 80 meg. -- and
old habits die hard (like saving space).
But, otherwise, I use alt+Prtscr a lot for other informal projects.
jim
To be strictly accurate, PrtScn (and Alt-PrtScn) give you a raw image in the clipboard; it's only what you then paste it into to save that decides what it's to be saved as. (I usually paste it into IrfanView, and then usually save it as a JPEG or GIF - usually GIF if I'm going to annotate it with text, ovals, and arrows, which is the usual reason I'm taking screenshots.) If you pasted it into Paint, then that used to only be able to save as bitmap, but the version of Paint in 7 has options.
It's a system provided function.
The various OSes have clipboard systems, capable of
carrying one or more data types or representations.
The graphics system is in "planes" and PrtScn only
captures one of the planes. Other tools are needed
to capture the 3D screen of a computer game.
FRAPS was the champ at that, and what it was doing,
was intercepting the calls to the graphics system,
using an injection DLL. But if you ran the FRAPS
installer while an AV like Kaspersky was running,
there would be a knife fight (the injection DLL
could get installed in a couple hundred places on
a busy machine, and AV programs don't like that).
FRAPS could capture ordinary 2D desktop or 3D game
frames. It is not compatible with W8 or W10 or W11 and
the person writing the code gave up on it. This is
all related to the graphics subsystems being made
inaccessible to programmable content (PVP and friends).
Win7 was the last OS, open to such activity. At around
the same time, VGA ports on video cards, were removed.
And before that, YPrPb was removed (three coax outputs),
capable of a lot more than 640x480.
Paul