Write a .php function to work in a .php script that generates .pdf files

Write a function to go with a provided .php script that generates .pdf files. The function must output text strings in different colors and combinations of capital and small letters, based on numbers within the strings. There are five possible rules that could be applied to any syllable in the string (so the boundaries are not only whitespace, but also the numbers themselves: in the string "gao1xing4", the "gao" and "xing" must be output using different formats because their numbers are different -- but with no space between them.) I have other scripts that accomplish this in .php for other uses, but I cannot figure out how to incorporate them into this script. I'll be happy to provide the other scripts that have solved the problem for other applications, for your reference or use. For example, see [login to view URL] and [login to view URL]