Université de Paris Sud
LRI bat 490
91405 orsay
email : cerin lri.lri.fr

A step by step approach to putting colour in TEX documents

Christophe Cérin

We have developed sets of macros to handle colour in TEX documents for one year. First of all "Vers l'introduction de la couleur dans TEX" [1] allows the marking out of text to change colour, layouts of rectangular boxes in colour, different kinds of shading on strings...When we change from one colour to another, we implement these tasks with PostScript operators. Hence our macros are dependant on translators dvi to PostScript. We use, for this, dvips from T.Rokicki.

The new set –version 2.3– we put forward for the meeting allows for rectangular boxes with uniform colour background, rectangular boxes with gradually shaded backgrounds and efficient graphics primitives as Bezier curves in colour and hachure circles for L^ATEX picture environment.

On this occasion, we'd like to comment on our general rules for the design of colour macros :

each time that we need to superimpose TEX boxes containing graphic objects or text ; each time we need to know dimensions of these boxes : do it with TEX ;
Moreover, each time we have to draw lines in colour, to put circles at a precise position on the page layer : do it with PostScript (a notion of current point is needed) ;

At last, we show that a strict discipline of specification and the use of programming concepts from classical languages leads to a good implementation in time and in disk space.