Here is a list of keywords and possible values:
/*
* PDF_get_parameter() and PDF_set_parameter() deal with strings,
* PDF_get_value() and PDF_set_value() deal with numerical values.
*/
/* setup */ /* value set for 3rd arg */
"compress" /* set_parameter */ | '[0-9]'
"resourcefile" /* set_parameter */ Free string
"FontAFM" /* set_parameter */ Free string
"FontPFM" /* set_parameter */ Free string
"FontOutline" /* set_parameter */ Free string
"Encoding" /* set_parameter */ Free string
"debug" /* set_parameter */ Free string (if 'c' is 1st char, compress off)
"nodebug" /* set_parameter */ Free string (if 'c' is 1st char, compress on)
"compatibility" /* set_parameter */ | '1.2' | '1.3'
"prefix" /* set_parameter */ Free string
"warning" /* set_parameter */
"binding" /* internal use only */
"flush" /* set_parameter */ |'none' | 'page' | 'content' | 'heavy'
/* page */
"pagewidth" /* set_value */ | float for pixel value |
"pageheight" /* set_value */ | float for pixel value |
/* font and text */
"textx" /* get_value */ | 0 |
"texty" /* get_value */ | 0 |
"font" /* get_value */ | 0 |
"fontsize" /* get_value */ | 0 |
"leading" /* set_value */ | cur_font_size + points down |
"textrise" /* set_value */
"horizscaling" /* set_value */
"textrendering" /* set_value */
"charspacing" /* set_value */
"wordspacing" /* set_value */
"underline" /* set_parameter */ | 'true' | 'false'
"overline" /* set_parameter */ | 'true' | 'false'
"strikeout" /* set_parameter */ | 'true' | 'false'
"fontname" /* get_parameter */ | 0 - 256 |
"capheight" /* get_value */ | 0 - 256 |
"ascender" /* get_value */ | 0 - 256 |
"descender" /* get_value */ | 0 - 256 |
/* graphics */
"currentx" /* get_value */ | 0 |
"currenty" /* get_value */ | 0 |
"fillrule" /* set_parameter */ |'winding'|'evenodd'
/* image */
"imagewidth" /* get_value */ | image file descriptor: > 0, < 256 |
"imageheight" /* get_value */ | image file descriptor: > 0, < 256 |
"resx" /* get_value */ | image file descriptor: > 0, < 256 |
"resy" /* get_value */ | image file descriptor: > 0, < 256 |
/* hypertext */
"openaction" /* set_parameter */ |'retain'|'fitpage'|'fitbbox'|'fitwidth'|'fitheight'
"transition" /* set_parameter */
"duration" /* set_value */