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, $height, 100);
    pdf_stroke($pdf_r);
?>