cpdf_setgray_fill
    (PHP 3>= 3.0.8, PHP 4 , PHP 5)
cpdf_setgray_fill -- Sets filling color to gray value
Description
bool 
cpdf_setgray_fill ( int pdf_document, float value )
     The cpdf_setgray_fill() function sets the current
     gray value to fill a path. Returns TRUE on success or FALSE on failure.
    
     See also cpdf_setrgbcolor_fill().