Using colors
Of course, Drawing routines can also render things in color. The color a particular rendering operation is to use is set before the operation using the pdf_setcolor() function

<?php
    pdf_setcolor
($pdf_r$fill_type$color_type$c1$c2$c3$c4);
    
pdf_circle($pdf_r$width$height100);
    
pdf_stroke($pdf_r);
?>