10 Color
TTH supports the coloring of text using the color package macros for
LATEX, supported by dvips (but not xdvi). TTH also supports the Plain
TEX colordvi macros contained in the package colordvi.tex that do the
same thing.
10.1 LATEX Color
The LATEX syntax is recommended because the 68 standard
named colors7 are directly supported internally by TTH using the named
model. Any numerical CMYK, RGB and Gray color can also be prescribed. For
example the following commands are enclosed in themselves:
\textcolor[named]{BrickRed}{...},
\textcolor[rgb]{0.,.5,0.}{...},
\textcolor[cmyk]{0.,.5,0.,0.3}{...}.
You can define custom colors in the usual way using, for example
{\definecolor{Puce}{rgb}{1.,.5,.8}
\color{Puce} This is my own Puce.}
Which gives "
This is my own Puce."
The command \pagecolor is supported but discouraged. It
is highly likely to give rise to an HTML file that will fail
validation because it inserts an HTML tag <body bgcolor=...>
which will not be in its correct position (immediately following the
title). The only way to be certain to produce an HTML file that passes
validation is to put the title and body commands in by hand, using
e.g. \special{html:<title>...</title><body ...>} Netscape
seems not to mind a body tag out of order, but only the first one is
able to set the page background color.
The commands \colorbox and \fcolorbox are supported via
CSS style sheet commands. They will only work to set the background
color of included text if the browser is set to use style sheets.
"This sentence" is the result of the command
\colorbox{green}{``This sentence''}. If it is colored, then
your browser supports style sheets to this extent. If not, check your
preferences settings.
10.2 Plain Color
The Plain TEX syntax using commands such as \Red{red text} requires
the file colordvi.tex to be input prior to their use. But
because TTH does not search the standard TEX paths, that file will
not usually be found unless the full path is explicitly
specified. If the file is not found, only the 8 standard colors
\Red, \Green, \Blue, \Cyan, \Magenta, \Yellow, \Black, and \White
are
recognized internally by TTH. You can use the user-defined CMYK numeric
style
\Color{0. .5 .5 0.}{pale red}
without the colordvi
file. It gives the result "pale red" but the
notation becomes cumbersome unless you define your color
e.g. like
\def\redcolor{0. .5 .5 0.}
\Color{\redcolor}{The stuff that is red.}
Another difficulty with the colordvi
command \textColor (which is the color switch - LATEX
syntax reversed that usage and changed to comma-delimited arguments
just to confuse us) is that it is a global setting. It then
becomes almost impossible to maintain proper nesting of the closure of
the font commands used for colors in HTML. As a result, use of
\textColor often gives HTML files that won't pass HTML validation.
10.3 Limitations
Color commands do not propagate into different cells of HTML tables
because of what may be regarded as a browser bug
[13.5]. For that reason, tables and equations will not color
correctly if the color commands enclose more than one cell (for
tables) or equation element. Remember also that some computers may be
limited in their color display capability, so the subtleties of colors
will be lost in some circumstances.