ftp.whtech.com/ftp.whtech.com.tar/ftp.whtech.com/club100/prt/fontfx.do

Text File | 2006-10-19 | 13KB | 241 lines

Club 100 Library - 415/939-1246 BBS,    937-5039 NEWSLETTER, 932-8856 VOICE


          CUSTOMIZING TYPEFACES ON THE EPSON FX PRINTER

                                        Jay Holovacs
                                        (Address any comments or questions)
                                        95 King George Rd.
                                        Warren, NJ 07060



              An excellent feature of the popular Epson FX series of
          printers is support for user-defined typefaces in printer RAM.
          For example, once a character set is downloaded into the
          printer, text from the TEXT utility or a word processor can be
          printed in the alternate typeface, or even switching back and
          forth between it and the standard face just as if it were a part
          of the printer ROM.  This allows for interesting possibilities
          including special typefaces (old English, extra bold, block,
          company logo) or even exotic foreign (such as Cyrillic, Hebrew
          or even 'Klingon' alphabets).  The characters are defined in a
          manner similar to graphics, however character definition is a
          separate capability, which can be printed much faster than
          constructing characters individually from graphics commands.
          Most of the special features, such as super and subscripts,
          underlining, emphasized print, proportional print, double strike
          and pica/elite will work with user supplied character sets.
              When I first started working with this feature of the
          printer, I soon found that the major problem with implementing
          these features as described in the Epson manual is the tedious
          conversion of pencilled graphics into binary codes follwed by
          preparation for the actual download into the printer.  To
          simplify this drudgery, I began to develop FONTFX.BA, a typeface
          editor program.  FONTFX allows for graphic editing, saving,
          downloading and modification of typefaces.  Type data can be
          stored in RAM, cassette or disk files (using Acroatix or
          Travelling Software DOS) for downloading at the start of a
          printing session or for future editing.  FONTFX is written for
          the M100 but is suitable for M200; users may want to modify
          screen placement to take advantage of the larger screen size,
          but this is not required.

          RUNNING FONTFX:
              You will first be prompted for the file name of an existing
          file to edit.  If this is a new session, simply hit Enter.
              The next screen is the command line.  Hit E for edit.  You
          will be prompted for an ASCII value to edit, then for its
          charistics: whether it is a descender character (such as 'y' or
          'g') and start and end of the character in dot columns.  To
          accept default characteristics, simply hit enter at each prompt
          (65='A', 'No' 0 and 11 are the defaults).  Once these entries
          are completed, the character is drawn on the screen (blank is
          default).  The characteristics can be changed later, so normally
          it is good to start with the defaults when first developing a
          character.










                               EPSON Typefaces     2

              Once in the Edit mode, the following choices are available
          as key-commands (use upper case for commands):

            EDIT returns you to the top of the edit screen, the ASCII or
            characteristics can then be changed.

            FILL the current pixel location (as indicated by the pixel
            cursors along the top and side of the character frame).

            CLEAR the current pixel.

            BLANK erases the currently selected character.

            MOVE is followed by a choice of 5 subcommands (Up, Down, Right
            Left and [enter]=abort).  Entering the key command will move
            the entire shape one pixel in the indicated direction.

            SAVE the current set of character definitions as a file (can
            be RAM, cassette, or with proper DOS, direct-to-disk).

            LOAD an existing character set file.  Note: if you have
            characters in the program, they will be overwritten by this
            command.

            DOWNload the current character set to printer.  You will be
            given the opportunity to select which ASCII values will be
            downloaded, also the opportunity to copy the ROM characters
            into RAM first (this allows default to any standard characters
            which have not been redefined.)

            TEST prompts for a string, which then will be printed out, for
            the purpose of evaluating the characters on paper.  You will
            be able to choose standard or proportional spacing.

            KLONE copies a specified ASCII into another.  This is a useful
            starting point for characters that are similar such as Q and O.

            QUIT exit program.  If changes have been made since last Save,
            you will be notified and given a chance to reconsider.

            Use the four ARROW KEYS to manipulate the bit cursor locations.

            KEY COMMANDS which prompt for additional information (Save,
            Load etc.) can be aborted by entering a null in response to
            the prompts.

          NOTE: When loading or quitting, a warning message will appear if
          the character data has been modified since it was last saved,
          providing the opportunity to save the current definitions before
          losing them.

          USING YOUR NEW TYPEFACE:

              PIXEL SPACING: The FX printer places a limitation on dot










                               EPSON Typefaces     3

          placement in that dots cannot be directly adjacent right to
          left, therefore a horizontal gap of at least one pixel must
          remain between pixels on the same row.  Pixels may be directly
          vertically or diagonally adjacent.  Even though the white space
          is quite noticeable on the screen, there is considerable overlap
          on paper and the result is not nearly so drastic as might be
          expected.  It is helpful to frequently download and test
          characters to get an accurate feel for the procedure.
              Simulating of curved lines and various slopes is not really
          as difficult as might be imagined from looking at the large
          character frame.  Use the Download feature frequently at first
          to get a good feel for the techniques of character description.
              Once created and saved, typeface files can be downloaded
          before a printing session by running FONTFX, loading the
          appropriate file and going directly to the Download command.
              Once the data is downloaded to the printer, the alternate
          typeface can be summoned by the sequence
          CHR$(27);CHR$(37);CHR$(N);CHR$(0).  If N=0 then standard
          typeface is used, if N=1 then RAM type is used.  Many word
          processing programs provide a means to embed control sequences
          like the above directly in your text.  Unfortunately, this
          command is not directly available in the standard text dump
          built into the M100 because it has no means to embed a CHR$(0),
          however the command can be sent from BASIC, then you can switch
          over to text to utilize the RAM type.
              DESCENDERS: When a descender is specified in the
          characteristics, the pixels are entered in the same manner as
          usual, however the entire frame will be shifted one pixel down
          on paper when the character is printed.
              PROPORTIONAL SPACING can be specified when printing with the
          usual embedded sequence--CHR$(27);CHR$(112);CHR$(1)--however you
          must supply the proportional information to the printer when
          editing the typeface.  The characters in the Epson FX consist of
          12 columns (numbered 0-11) by 8 rows.  The 12th column is always
          blank.  The user can specify the start and end positions which
          the printer will use when in porportional mode (in standard mode
          the full width is always printed).
              Once you get the character visually the way you like it,
          center it appropriately in its work area, so that the character
          will be centered when printing in nonporportional mode as well.
          Hit E to get back to the top of the editing sequence and
          re-enter the ASCII.  Determine the first column which will be
          considered to start the character (it may include one or two
          blank columns in front of the actual character) and enter this
          value, then enter the ending column (which must be at least 5
          greater than the start position).  The character is now ready
          for proportional printing.  The editor will still accept data
          for all columns, and this data will be saved in files, but data
          beyond the last column specified will be ignored by the printer
          when in proportional mode.

          BOTH DESCENDER DATA AND LENGTH DATA CAN BE CHANGED AS DESIRED BY
          RE-EDITING A CHARACTER.











                               EPSON Typefaces     4

          COMMENTS ON THE PROGRAM:

              PROGRAM STRUCTURE: In order to keep the program logic 'wide
          open' for user modification, FONTFX as listed here is clearly
          not trimmed back in size.  Extensive comments, and mnemonic
          (rather than 2 character) variable names are used.  Packing this
          program, either by hand or using a packer program will
          significantly cut this size if size is critical.  Additionally,
          the structure is strongly modular in nature, with the purpose of
          each module defined by its comments.  BASIC by its nature does
          not enforce structure (as Pascal, C or others), however, taking
          the effort to construct the program with a structured philosophy
          from the beginning helps significantly as the program expands
          beyond its original concept.
              To keep the file size compact, I have restricted the
          changeable ASCII's to 33-127 which is the range normally used by
          text type programs, however the Epson will accept 255 different
          characters.  By changing DIMensions of CD and altering the value
          subtracted from CHAR in lines 910 and 911, you can modify to
          define as many characters as desired.
              ERRORS: A significant amount of time goes into the design of
          a typeface, therefore it is important to be able to recover in
          running condition from an IO error; file errors are fairly
          extensively trapped, with error messages; the more common file
          errors will not stop the program.
              Lines 1615-1620 cover disk access errors (Acroatix, these
          lines can be user modified for TS or similar DOS) and can be
          deleted if you are not using the portable disk drive.
              Line 1690 is a catch-all for miscellaneous errors.  Program
          execution stops, and if you can fix the problem by changing
          value of an offending variable (NOT by changing a program line
          however) and resuming at the same statement, the program can
          then be CONTinued without losing the current work.
              Note that line 1608 RESUMEs to line 100 rather than to the
          subroutine level of the error statement.  From what I can
          gather, when a memory overflow error occurs, the subroutine
          stack is lost; and the program must resume at its lowest level
          (I have only tried this technique on the M100).  All other types
          of errors that I have encountered can be RESUMEd on the same
          level from which the error occured.