On 2024.07.07 17:06, Mark Knecht wrote:
[snip...]
So I understand the 14% calculation, but help me understand the
underlying
technology. Is the DPI how a font file, which I presume is some fixed
size,
like 25x25, gets scaled onto the screen? I'm not clear about the
conversion
from the font to the number of dots used to draw the font on the
screen.
When a program requests the system to display a character on the
screen, depending on the specific font and the available font-drawing
libraries, it can specify the size either in dots or some physical
measure - inches, or more likely points. Points are an "ancient"
measure from the times of using real, lead type, stored in wooden
cases, thus upper [capital letters] and lower [everything else] case.
There are 72 points to the inch. 10 point type is 10/72" tall, but
with enough spacing between rows, you typically get 6 rows per inch.
(Sorry for being pedantic - many years ago I did spend some time
printing with hand set type.)
To how fonts are designed, many if not most modern fonts (such as
true-type) are specified internally by the commands to draw each
character, and you request the size in points. The conversion to how
many pixels to use is based on the DPI the system thinks is being used
by the monitor. Some fonts are actually specified by the Width x
Height in pixels. These are bitmap fonts, which often come in sets of
various sizes. Fortunately (as far as I can tell) there are fewer and
fewer bitmap fonts in use any more, as they need to get very larger for
higher DPI displays. You can imagine that mixing the two is even more
likely to lead to confusion and poor looking display, unless you are
extremely careful.
With my limited understanding it seems very arbitrary.
Not so arbitrary, but easily confusing.
With respect to Dale's "huge" problem there's also a scale factor in
KDE
that can be set by the user, or could be set wrong such that it will
scale
up what's drawn on the screen. (Display and Monitor->Global Scale)
And I'm really not sure where this scaling is applied relative the the
points to pixels calculation of font size.
Hope this helps more than confuses.
Jack
