Coloured text

Introduction to coloured text
Index of colour macros

Introduction to coloured text

For example, say you want to have the name "Jack" in the sentence "All work and no play makes Jack a dull boy" appear in yellow. You'd begin by telling mom about the colour, yellow. There are two ways of doing this; see NEWCOLOR and XCOLOR for a full explanation of the difference between the two. If you use XCOLOR, you'd enter this:

	.XCOLOR yellow

	.NEWCOLOR yellow RGB #FFFF00

	All work and no play makes \*[yellow]Jack\*[black] a dull boy.

	All work and no play makes
	.COLOR yellow
	Jack
	.COLOR black
	a dull boy.

For information on using colour during document processing, see Colour support in document processing.

Please note: Mom's colour support is for text only. She doesn't support "fill" (or "background") colour for drawn objects. Please also note that if you're accustomed to using groff's .defcolor to define colours, and groff's inline \m[<colorname>] to call them, you may continue to do so without confusing mom.

Index of colour macros

• NEWCOLOR
• XCOLOR
• COLOR
• \*[<colorname>] inline escape

NEWCOLOR lets you create a colour, rather like an artist mixing paint on a palette. The colour isn't used immediately; NEWCOLOR merely tells mom how to mix the colour when you need it. If you haven't invoked NEWCOLOR (or XCOLOR), mom doesn't have a clue what you mean when you reference a colour (with COLOR or \*[<color name>]).

The first argument to NEWCOLOR is a name for your colour. It can be anything you like--provided it's just one word long--and can be caps, lower case, or any combination of the two.

The second argument, which is entirely optional, is the "colour scheme" you want mom to use when mixing the colour. Valid arguments are RGB (3 components, red green blue), CYM (3 components cyan yellow magenta), CMYK (4 components cyan magenta yellow black) or GRAY (1 component). If you omit the second argument, mom assumes you want RGB.

The final argument is the components of your colour. This can be hexadecimal string starting with a pound sign (#) (for colour values in the 0-255 range) or two pound signs (##) (for colour values in the 0-65535 range), or it can be a series of decimal digits, separated by spaces, one digit per component, with the argument enclosed in double quotes. (If this is all gibberish to you, see Tips for newbies.)

Thus, to tell mom about a colour named "YELLOW", you could enter one of the following:

	.NEWCOLOR YELLOW #FFFF00         \"or ##FFFFFFFF0000 or "1 1 0"
	.NEWCOLOR YELLOW RGB #FFFF00     \"or ##FFFFFFFF0000 or "1 1 0"
	.NEWCOLOR YELLOW CYM #00FF00     \"or ##0000FFFF0000 or "0 1 0"
	.NEWCOLOR YELLOW CYMK #00FF0000  \"or ##0000FFFF00000000 or "1 1 0"

Tips for newbies

Alternatively, you can use mom's simpler XCOLOR macro to initialize one of the 256 pre-defined X colours by supplying the name of the color as an argument.

XCOLOR is similar to NEWCOLOR in that it tells mom to initialize a colour, but it's easier to use. All you have to do is pass it, as an argument, the legal name of one of the 256 pre-defined X colours. The name must be all one word, and, breaking with mom policy, it must be entered in lower case.

For example, if you want to intialize the X colour, coral, all you have to do is enter

	.XCOLOR coral

	.COLOR coral

The downside of XCOLOR is that you can't create custom colours. This restriction, however, is mitigated by the fact that for many users, 256 colours is more than enough to play around with.

While some X colours have fanciful names (peachpuff, papayawhip, thistle, snow), many are self-explanatory and self-descriptive in ordinary colour terms. "blue" is pure (rgb) blue, "green" is pure (rgb) green, and so on. Furthermore, for many X colors, there exist four variants, each representing increasingly darker shades of the same colour. For example, "blue" (and "blue1") are the brightest forms of (rgb) blue; "blue2", "blue3" and "blue4" are increasingly darker shades of the same blue. For that reason, you may find XCOLOR is a better choice than NEWCOLOR when it comes to initializing common colors.

The whimsical nature of X colour names sometimes makes for names that are long to type in, e.g. "mediumspringgreen". The optional second argument to XCOLOR allows you to come up with more convenient name by which to reference the colour. For example, you could enter

	.XCOLOR mediumspringgreen mygreen
	    or
	.XCOLOR mediumspringgreen MYGREEN

Finding X color names

A better way to get the colour names, as well as to see what the colours look like, is to fire up a colour chooser (like xcolorsel) that both lists the colour names and shows a swatch of the colour as well.

Whichever method you use to find X color names, remember that the names, passed as arguments to XCOLOR, must be all one word, all in lower case.

Once you've told mom about a colour (via NEWCOLOR or XCOLOR), you use either the macro, COLOR, or the inline escape, \*[<colorname>], to cause mom to set subsequent text in that colour. See the example, above, which shows both in action.

NOTE: You can use the \*[<colorname>] inline escape in any document processing macro that takes a string argument. However, you must remember to reset the colour at the end of the argument (typically with \*[black]) unless you want all subsequent invocations of that particular macro to be colourized.

Furthermore, if you use \*[<colorname>] in the string argument passed to .HEAD, .SUBHEAD or .PARAHEAD, and you've requested that any of these types of heads be numbered, the numbers themselves will not be coloured, only the text you passed the macro. If you wish the numbers to be colourized as well, you must explicitly tell mom that you wish all of the head(s), subhead(s) or parahead(s), including the numbers, colourized by invoking the appropriate control macro.