Arachne COLOR rendition Howto                                00/07/31
Written by Clarence Verge

Part 1 - The Technobabble:

Arachne is pre-programmed to respond accurately to ONLY the original
M$ set of standard HTML color names. These colors are a holdover from
the limitations imposed by digital (on/off) video signal levels.

The three colors Red, Green and Blue can only be combined eight ways
in an on/off fashion. If you add one more digital signal representing
intensity, this doubles the possibilities to 16.

If 0 represents off and 1 represents on, we can get the following IRGB
combinations:

     Intensity Red Green Blue   Visual result
           0    0    0    0     Black
           0    0    0    1     Dark Blue    (Navy)
           0    0    1    0     Dark Green   (Green)
           0    0    1    1     Dark Cyan    (Teal)
           0    1    0    0     Dark Red     (Maroon)
           0    1    0    1     Dark Magenta (Purple)
           0    1    1    0     Dark Yellow  (Brown/Olive)
           0    1    1    1     Dark White   (Gray)
           1    0    0    0     Bright Black (Gray)
           1    0    0    1     Blue
           1    0    1    0     Green        (Lime)
           1    0    1    1     Cyan         (Aqua)
           1    1    0    0     Red
           1    1    0    1     Magenta      (Fuchsia)
           1    1    1    0     Yellow
           1    1    1    1     White

It can be seen that there is a duplicate definition for Gray leaving
a spare combination available when these values are translated to
levels for analog video (VGA) use.

These are the 16 widely known color names with their Hex RGB intensity
values. A Hexadecimal value of 00 is off or dark, FF is on maximum or
bright, and 80 is on at half intensity. Mostly equivalent to the above:

    Black  = #000000    Green  = #008000
    Silver = #C0C0C0    Lime   = #00FF00
    Gray   = #808080    Olive  = #808000
    White  = #FFFFFF    Yellow = #FFFF00
    Maroon = #800000    Navy   = #000080
    Red    = #FF0000    Blue   = #0000FF
    Purple = #800080    Teal   = #008080
    Fuchsia= #FF00FF    Aqua   = #00FFFF

Here we see that the extra GRAY condition has been raised to SILVER,
an intensity a little higher than 1/2 way between gray and white.
This would be impossible without the fine variations possible due to
the use of an analog video signal.

To use this capability further requires the use of SVGA or HiColor.
The 4bit combinations can define only 16 colors, 8bit combinations
can define 256 colors, and 24 bit combinations as show above where
a full eight bits is used for each of R G B, can produce 16.7 million
colors. This is called TrueColor.  HiColor is a 16 bit mode.

It is important to note that except for Hicolor, the second character
in each Hex pair has no effect.  Taking only the 16 levels specified
by the most significant hex digit of each color, a total range of 4096
colors can be specified. (16x16x16)  In fact, if you skip every second
Hex character in the first digit, it is still possible to specify 512
colors, or twice as many as the 8bit (256 color) video modes support.

So, the above Hex HTML color specification must be reduced severely by
software to fit the limitations of the video mode.
You can pretty much ignore the low nibble character.



Part 2 - The Suggestions:

Arachne (and the other browsers) respond to color names other than the
above standard 16, but not in an easily predictable manner. Some of the
big browsers support names like cadetblue or chocolate or even cyan but
Arachne renders cyan the way the big boys would render "roadkill".

After checking for the "#" character first and the 16 known names next,
Arachne takes the first six characters of the color spec. and treats it
as hexadecimal whether it is or not. So the word cyan, containing only
four characters, will convert to a color without any blue in it.
In fact, as pointed out above, the second character has no real effect
either on the result, so only the letters "c" and "a" are used.  These
happen, by chance, to be legal hex characters. Arachne displays yellow
for cyan which is almost exactly the opposite to what is intended.

The safe approach for both local Arachne use and pages online, is to
use only the standard 16 agreed upon color names as far as possible,
and for any other required color specification use Hex RGB values.

Remember that others may not be viewing anything even close to what
YOU might be seeing if you use 24 bit RGB specs, and they CERTAINLY
won't see what you intend if you put your Xmas message up in red and
green and they view it in monochrome. :(

Arachne has a page review capability unparalled by the other browsers.
View ARACOLOR.htm to see the effect of video mode on Arachne pallette.
Use Video Setup, found on the Aracolor or Options pages to change your
video mode and check out your pages. Remember to try a grayscale mode.

The top 16 color bars are the 16 standard named colors. On the left in
the bottom half you can see the effect of stepping by 2 in intensity
for grayscale. You will also probably notice that in *16* color modes
purple and fuchsia look the same, and at the bottom there is a gray
bar that is brighter than silver (C0C0C0).  I don't know yet if this
is a bonus color provided by my video boards or an Arachne special.
The code I have examined to date shows Arachne translating FUCHSIA
to #FF00FF, not #800080 and NO word is coded to be = #E0E0E0.

If three colors each having possible intensities of off, on and bright
are available, 27 combinations are possible.  The bottom right side of
ARACOLOR.htm shows most of the 11 combinations that are not used in the
standard 16.  Take care to note that most of these combinations become
indistinguishable from SILVER when a 16 color video mode is used !!
Try Arachne in 16 color mode and toggle monochrome with the "!" key.

Arachne does not require the color name to be in uppercase and she does
not require quotes around color names. She does require the leading "#".

Video setup is also useful to see how wide your page looks in 640x480.

Press your back button to return to Arachne. 8-)