Hi Ken,
To uncomment any code under function display_backdrop() does not
make the raster display work. There are basically two version of this
function. Each part of the code are commented separately. With you and
other people's responses now I believed that this part of the functionality
of xdigit is still under the developement.
Thank you for all the people response to my question.
PK Lin
E-mail: pklin@cerf.net
Tel: (617) 942-1655