Re: Speaking of fonts...

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 10 Jul 2006, Tim wrote:

On Sun, 2006-07-09 at 20:03 -0400, Tom Horsley wrote:
If I correctly set the DPI for my Westinghouse LVM-42w2
42" 1920x1080 dpi monitor, the setting is 52dpi, and at
52 dpi everyone seems to draw fonts that are somewhere
around 4 or 5 pixels high and mostly unreadable even
if you paste your eyeball to the screen :-).

Yep, you're stuffed, because the people providing those options haven't
understood the situation properly (those who design font rendering
engines, and those who get you to set font sizes in pixels in web
browser configurations).  I get the same thing (stupid font sizes).

DPI means how many dots per inch, or pixels in that inch, will be used
to draw the character (how smooth the edges are).  It has *NOTHING* to
do with how big the character should be drawn.

There's no magic about "points" either. There are 72 of them in an inch and that's all one needs to know about them.


Geez, that problem was dealt with properly on printers ten years ago.
Changing your printer from 24 DPI to 48 DPI, for example, didn't change
the font sizes, unless the driver was written by a complete and utter
moron.  You just got smoother looking fonts, at the same size.

Right. The printer just doubled the number of dots in an inch--it slowed dot-matrix printers to half speed and used twice as much ink.

But the printer or its device-specific driver knows how wide/tall a sheet of paper is and the DPI in any mode is fixed. So it's easy for the printer or driver to know how many dots are in a point.

Displays can't change the number of dots in an inch. Display drivers could prespecify the DPI, and I don't really know why they don't. But to get accurate characters, the display driver needs to know the right number of DPI (and that's really it). The same screen resolution (in pixels) will have different DPI settings depending on the physical size of the screen. 1280x1024 on a 17-inch CRT necessarily means more DPI than 1280x1024 on a 19-inch CRT and that's more than 1280x1024 on a 19-inch LCD.

The font-scaling math converts, say, 8-point type (1/9-inch high) to the best representation it can get given that there are 96 (or 52, or 84, or 114) actual pixels in an inch.


In this day and age of using scaled/vector type of fonts, for just about
everything, I don't know why this old, treat it like a bitmap, stupidity
still exists.

Ultimately, modern low-cost displays and printers *are* just bitmaps. Even if the electron guns draw vectors like they did in the early days of high-end graphics, the image is drawn on phosphors on the screen (pixels). All the vector math is devoted to converting the vector description to the best possible bitmapped rendering.

LCD displays have the additional ability to use the colored subpixels to get even better effects. But to do the conversion accurately, one needs to know how to map points to pixels, i.e., the true DPI.

--
		Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs

--
fedora-list mailing list
fedora-list@xxxxxxxxxx
To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
[Index of Archives]     [Older Fedora Users]     [Fedora Announce]     [Fedora Package Announce]     [EPEL Announce]     [Fedora Magazine]     [Fedora News]     [Fedora Summer Coding]     [Fedora Laptop]     [Fedora Cloud]     [Fedora Advisory Board]     [Fedora Education]     [Fedora Security]     [Fedora Scitech]     [Fedora Robotics]     [Fedora Maintainers]     [Fedora Infrastructure]     [Fedora Websites]     [Anaconda Devel]     [Fedora Devel Java]     [Fedora Legacy]     [Fedora Desktop]     [Fedora Fonts]     [ATA RAID]     [Fedora Marketing]     [Fedora Management Tools]     [Fedora Mentors]     [SSH]     [Fedora Package Review]     [Fedora R Devel]     [Fedora PHP Devel]     [Kickstart]     [Fedora Music]     [Fedora Packaging]     [Centos]     [Fedora SELinux]     [Fedora Legal]     [Fedora Kernel]     [Fedora OCaml]     [Coolkey]     [Virtualization Tools]     [ET Management Tools]     [Yum Users]     [Tux]     [Yosemite News]     [Gnome Users]     [KDE Users]     [Fedora Art]     [Fedora Docs]     [Asterisk PBX]     [Fedora Sparc]     [Fedora Universal Network Connector]     [Libvirt Users]     [Fedora ARM]

  Powered by Linux