Perhaps others might be interested in a low level windowing toolkit.

Some screenshots are here;
> http://xforms-toolkit.org/screenshots/

The GNU project page is here;
> http://savannah.nongnu.org/projects/xforms/

The home page is here;
> http://xforms-toolkit.org/

I did some dead end conversion of the XForms.Lib C function headers to 
FreePascal available here;
> http://www.sytekcom.com/eng/Freepascal_XForms_Units.html

And some more dead end conversion of examples here;
> http://www.sytekcom.com/eng/Freepascal_XForms_Demos.html

Using the FreePascal functions requires some FreePascal setup, which I 
don't advocate for the impatient. One point to make is that FreePascal 
is NOT case sensitive, but C is. I simply use long descriptive names to 
help me read the code. I have no idea how people read C.

FreePascal compiles and links to any C code, however. Even the GNU C 
library. You can really dig into the linux core, and read what you're doing.

Of note with the XForms screenshots is science lab and factory controls. 
Since XForms runs right off Xlib functions, it is as close to a base 
windowing kit I know of. NCurses and Direct Framebuffer perhaps the 
exception.

I don't believe the timer functions are close to high precision for 
XForms. But if you're looking for some GNU instrumentation window 
controls, this might be of interest.