= Print: printing system     include "print.m";    print := load Print Print->PATH;     Print: module    {         PATH: con "/dis/lib/print/print.dis";         CONFIG_PATH: con "/lib/print/";             init: fn(): int;         set_printfd: fn(fd: ref Sys->FD);         print_image: fn(p: ref Printer, display: ref Draw->Display, im: ref Draw->Image, pcwidth: int): int;         print_textfd: fn(p: ref Printer, fd: ref Sys->FD, ps: real, pr: int, wrap: int): int;         get_defprinter: fn(): ref Printer;         set_defprinter: fn(p: ref Printer);         get_size: fn(p: ref Printer): (int, real, real);  # dpi, xinches, yinches         get_printers: fn(): list of ref Printer;         get_papers: fn(): list of ref Paper;         save_settings: fn(): int;         # Printer types            Ptype: adt {             name: string;             modes: list of ref Pmode;             driver: string;             hpmapfile: string;        };                # Paper sizes                Paper: adt {             name: string;             hpcode: string;             width_inches: real;             height_inches: real;        };                # Print modes                Pmode: adt {             name: string;             desc: string;             resx: int;             resy: int;             blackdepth: int;             coldepth: int;             blackresmult: int;        };                # Print options                Popt: adt {             name: string;             mode: ref Pmode;             paper: ref Paper;             orientation: int;             duplex: int;        };                # Printer instance                PORTRAIT: con 0;        LANDSCAPE: con 1;                DUPLEX_OFF: con 0;        DUPLEX_LONG: con 1;        DUPLEX_SHORT: con 2;                Printer: adt {             name: string;             ptype: ref Ptype;             device: string;             popt: ref Popt;             pdriver: Pdriver;        };            };        Pdriver: module    {         PATHPREFIX: con "/dis/lib/print/";         DATAPREFIX: con "/lib/print/";             init: fn(debug: int);         sendimage: fn(p: ref Print->Printer, tfd: ref Sys->FD, display: ref Draw->Display, im: ref Draw->Image, width: int, lmargin: int): int;         sendtextfd: fn(p: ref Print->Printer, pfd, tfd: ref Sys->FD, ps: real, pr: int, wrap: int): int;         printable_pixels: fn(p: ref Print->Printer): (int, int);        };    The  Print module provides an interface to one or more printers.    The Print moduleinit() Init must be called once to  initialise  the  internal       state of Print. set_printfd(fd)       set_printfd  provides a file descriptor to be used for       output. By default, output is  sent  to  the  file  or       device specified in the Printer adt. print_image(p,display,im,pcwidth)       print_image  prints  a page containing a single image.       The image is centred horizontally, and is scaled up to       fill  the  percentage of the available width specified       by pcwidth. print_textfd(p,fd,ps,pr,wrap)       print_textfd prints one  or  more  pages  of  text  on       printer  p  from the file open for reading on fd.  The       point size is controlled by p.  If  the  printer  does       not  support  the  specified point size an alternative       size will be used.  A point size of 0.0 can be used to       select  the printer's default size (usually 12 point).       If pr is non-zero, a proportionally-spaced  font  will       be  used  (if  available).  If wrap is non-zero, lines       will be wrapped if they overflow the  page  width  (if       this feature is supported by the printer). get_defprinter()       get_defprinter   returns   the   default  printer  (in       /lib/print/defprinter). set_defprinter(p)       set_defprinter   sets   the   default   printer    (in       /lib/print/defprinter). get_size(p)       get_size  returns  the resolution in dots per inch and       the total number of pixels available for  printing  in       the  x  and y direction.  Before calling this function       the orientation should be set if required. get_printers()       get_printers returns a list of all available  printers       (in /lib/print/printer.cfg). get_papers()       get_papers returns a list of all available paper sizes       (in /lib/print/paper.cfg).    Data StructuresPtype        - specifies a Printer Type, with fields:        name:  Name used to refer to this printer type        desc   Description        modes  List of supported print modes        driver:              The .dis  file  specification  of  the  printer              driver        hpmapfile:              For HP printers, the name of the color map file Paper        - specifies the dimensions of a type of paper        name:  Name used to refer to this paper size        hpcode:              For  HP  printers, PCL code used for this paper              size        width_inches:              Width of paper in inches        height_inches:              Height of paper in inches Pmode        - specifies a print mode        name:  Name used to refer to this print mode        desc:  Description        resx:  X resolution in dots per inch        resx:  Y resolution in dots per inch        blackdepth:              Depth of black component in bytes        coldepth:              Depth of color components in bytes        blackresmult:              Resolution multiplier  of  black  component  (1              means same as base x resolution) Popt        - specifies a set of Print Options        name:  Name  of a Printer to which these print options              apply        mode:  The name of a print mode        paper: The name of a paper size        orientation:= Paper orientation: either  PORTRAIT  or  LAND‐              SCAPE        duplex (NB DUPLEX IS NOT CURRENTLY SUPPORTED):= Duplex  setting: DUPLEX_OFF or DUPLEX_SHORT or              DUPLEX_LONG Printer        - specifies a printer instance        name:  Name used to refer to this printer        ptype: The printer type        device:              The name of the file to be used for output  (eg              /dev/lpt1data)        popt:  The print options        driver:              The printer driver module handle    Configuration FilesThere  are  configuration  files  to  initialize  the PrinterTypes, Print Modes, Paper Sizes  Printers  and  Print  Modes.They  all have a similar format, with fields corresponding tothe relevant adt.  Here is  an  extract  from  the  paper.cfgfile: A4=     hpcode=26     width_inches=8.3     height_inches=11.7A5=     hpcode=25     width_inches=4.15     height_inches=5.85 Aliases can also be defined, such as myA4=A4 The  final  configuration file, defprinter, just contains thename of the default printer. == files/lib/print/*.map       HP color maps. /lib/print/ptype.cfg       Print Type configuration file. /lib/print/pmode.cfg       Print Mode configuration file. /lib/print/paper.cfg       Paper Size configuration file. /lib/print/printer.cfg       Printer Instance configuration file. /lib/print/popts.cfg       Print options configuration file. /lib/print/defprinter       Holds the name of the default printer. Not  needed  if       there is only one printer available. == source/appl/lib/print/print.b       Implementation of the Print module. /appl/lib/print/*_driver.b       Printer-specific driver modules /appl/lib/print/scaler.b       Scaler module == see ALSOdraw-image(2), image(6)