OS2 World Community Forum

OS/2, eCS & ArcaOS - Technical => Programming => Topic started by: Martin Iturbide on February 23, 2017, 03:28:35 pm

Title: Questions about GPI?
Post by: Martin Iturbide on February 23, 2017, 03:28:35 pm
Hi

I need to keep updating the EDM/2 API Project with the GPI functions, but I was wondering a few things and I don't know if someone with knowledge on this area can answer me this questions.

I understand that GPI are the drawing functions that allows the GUI to be "draw" on the computer and it is referenced a part of PM.  I was wondering what would a similar library to GPI on the open source world.

I understand that Qt is more similar to the other windows related functions in PM, but I'm not sure about GPI.

Also, On OS/2 Qt depends on PM (on the port Qt make calls to PM to draw the things on the screen), how Qt works in the Linux world? under which libraries does it run?

Regards
Title: Re: Questions about GPI?
Post by: Pete on February 23, 2017, 09:19:04 pm
Hi Martin

I think x is the underlying library for qt (kde desktop) and gtk (gnome desktop) libraries - long time since I did any programming in linux though and then it was only briefly.

Hopefully someone with more knowledge will either correct me or expand on the above.


Regards

Pete
Title: Re: Questions about GPI?
Post by: Dave Yeo on February 23, 2017, 11:58:34 pm
Yes X is the underlying drawing surface usually on *nix, there's also XCB which is sorta part of X, a couple of new ones in the works such as Wayland, and the framebuffer for what we'd call a full screen session.
There's also libraries such as Cairo that are implemented on X or XCB (as well as most other OSes) that are more low level then something such as QT.
I'd guess that ReactOS has something very similar to GPI that is open source
Title: Re: Questions about GPI?
Post by: Alex Taylor on February 24, 2017, 12:51:01 pm
I suspect GRE (GRaphics Engine) is more like the equivalent to X.

GPI is our primitives drawing and layout layer. So yes, libraries like Cairo (for general graphics) or Harfbuzz (for text) are probably the closest equivalents in the OSS world.
Title: Re: Questions about GPI?
Post by: Martin Iturbide on February 24, 2017, 09:55:07 pm
Thanks for the replies.

Checking more on Cairo, I also found Pixman (which Cairo needs), it is "a low-level software library for pixel manipulation, providing features such as image compositing and trapezoid rasterization." It is ported to OS/2 but it seems that the original project does not offer much documentation about it's API, but looks interesting.

Regards