Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!mailrus!bbn!spdcc!bloom-beacon!sparky.UUCP!jdi
From: jdi@sparky.UUCP (John Irwin)
Newsgroups: comp.windows.x
Subject: physical screen dimensions on a Sun
Message-ID: <8811010704.AA01663@sparky>
Date: 1 Nov 88 07:04:28 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 37


The Release 3 (R2 also) server returns bogus values for the physical screen
width and height of a Sun (in millimeters).  The relevant code from the
monochrome initialization routine (it's much the same for a color screen)
looks like:

    if (!mfbScreenInit(index, pScreen,
			   sunFbs[index].fb,
			   sunFbs[index].info.fb_width,
			   sunFbs[index].info.fb_height, 90, 90))
	   ...

The 90's are the values for dots-per-inch (horizontal and vertical).
So on a high-res screen (1600x1280) the server says the physical screen
dimensions are much larger than on a normal screen (1152x900), which is
incorrect.

Pulling out my trusty ruler I find that the Sun screen I use is 13.75 inches
in width and 11 inches in height.  (About 17 diagonal inches)  This trans-
lates to about 82dpi for the normal screen and 115dpi for the high-res
screen.  Is 90 supposed to be a compromise?  :-)

So we went about looking for a way to query the operating system (or
whatever) to determine how big a physical screen you've got.  Guess what?
There doesn't appear to be a way!  NeWS 1.1 also doesn't appear to have a way
to get the physical screen dimensions.  This is especially amusing given that
NeWS is touted as being "pixel size independent."

Knowing the physical dimensions of the screen is critical to providing
some sort of pixel independence.  The new Release 3 fonts are wonderful,
but it's hard to know how to translate a desired point size into an actual
font choice on a Sun.  Asking the user to measure his screen when he starts
a client doesn't seem like much of an option.  :-)

Anyone know how to solve this problem?  (hacks welcome)

	-- John Irwin, Franz Inc.  jdi%franz.uucp@ucbarpa.berkeley.edu