GNOME 3 - font point sizes now scaled?

[Daniel Drake]

Hi,

I'm working on bringing OLPC up-to-date with all the great efforts
with GNOME 3, systemd, etc.

On the OLPC XO laptops we have quite a strange screen - it is small
(152mm x 114mm) but very high resolution (1200x900 i.e. 201 dots per
inch).

Previously, on Fedora 14, we had to adjust the default GNOME font
sizes since they didn't look right on the screen (I think they were
too big). Now I'm looking at applying the same set of customisations
to Fedora 16 since the default fonts are uncomfortably small on our
display.

However, I've noticed a fundamental difference in the sizing of fonts
between Fedora 14 and Fedora 16. This is visible with a simple
experiment:

1. Open gedit
2. Change document font size to Sans 72
3. Write the capital letter "I" and measure the height of the printed
character with a ruler

I do this on two laptops side by side, one running Fedora 14 and the
other running Fedora 16.
On F14 the height of the I character is 1.9cm, and on Fedora 16 it is
0.9cm. That is quite a difference.

On both laptops, xdpyinfo correctly prints the screen resolution, DPI
and display size, which have not changed.

>From a typographic standpoint, F14 seems to be correct here. As 1pt is
(approx) 1/72 of an inch, size 72 should produce characters of around
1 inch in size - and 1.9cm (the F14 measurement) is about an inch.

Also, Cantarell seems to play by its own rules. On F16, the "I" in
Cantarell 72 is 0.8cm, not too different from Sans 72, but the
difference between Sans 11 and Cantarell 11 is more significant - at
size 11, Cantarell is tiny.

Can anyone help me understand this behaviour?

Thanks,
Daniel