From: pdh@netcom.com (P D H) Subject: adding more color to Linux Date: Sat, 1 May 1993 12:13:33 GMT
I am going to examine what I can do to modify the console driver so that
the VGA palette and DACs can be loaded with exact color values desired.
For text modes, all this will do is allow choosing some other 16 colors
from the larger set of 262144 (or more in some SVGA systems).
In planning for this I want to consider how best to do this, and am seeking
input and ideas. I'd prefer to read those that include arguments and reasons
for that particular idea.
Here are the directions I am thinking of so far:
1.
Since ANSI color is already done with escape sequences, I would like to do
the extended color with special escape sequences as well. The advantages
of this include that the remote application program in a telnet session
could do the color settings just as it can now for ANSI color.
So the next question in this area is what form the sequence should take.
One approach is to add larger numbers to the existing (ESC [ m) sequence
now used to set ANSI colors. An alternative is to create some new special
seqeuence.
2.
I could also (or only) add ioctl function codes for setting (and even
obtaining) the palette values.
Seeking:
Input with suggestions that consider the needs of current and future VGA
boards with more than the standard VGA colors. I am particularly interested
in a model to allow setting colors where a program can take full advantage
of better color systems, and still get approximate values with lesser color
systems.
An example of something I want to avoid doing is assuming a certain number
of registers. For example if I define a sequence or ioctl to load the DAC
registers, I should not assume there are 256 registers.
Future:
Even more features of VGA such as:
Adjustable number of rows by changing the number of scan lines or the
number of scan lines per cell. For example in MS-DOS I set the number
of scan lines per cell to 10 (instead of 8) and change the 50 row mode
into a 40 row mode. It's still the same mode number. This does involve
changing the fonts, because of the larger cell. I just added a blank
scan line above and below, except for things like border lines.
-- | Phil Howard, pdh@netcom.com, KA9WGN Spell protection? "1(911)A1" | | Right wing conservative capitalists are out to separate you from your MONEY | | Left wing liberal do gooders are out to separate you from EVERYTHING ELSE!! | +-----------------------------------------------------------------------------+