Sets the position of text for the next cpdf_show() call.
pdf_document
The document handle, returned by cpdf_open().
x_coor
The x-coordinate of the text position
y_coor
The y-coordinate of the text position
mode
The optional parameter mode
determines the unit length. If it is 0 or omitted the default unit as specified
for the page is used. Otherwise the coordinates are measured in postscript
points disregarding the current unit.