Internet Surfer 2.0/Internet Surfer 2.0 (Wayzata Technology) (1996).iso/pc/text/mac/faqs.282

Text File | 1996-02-12 | 28KB | 617 lines

Frequently Asked Questions (FAQS);faqs.282



   Character fill algorithms

   The fill algorithm in PostScript tends to turn on too many pixels and
   make a character fatter and wider by one or two pixels. This is
   especially obvious in small sizes at low resolutions. Both Adobe and
   Kingsley/ATF compensate for this, thus keeping characters to proper
   thickness.

   Other type vendors do not currently compensate for the fill algorithm
   and thus end up with undesirably heavy characters, which is
   particularly noticeable at small sizes.

   Optical Scaling*

   Optical Scaling modifies the relative shape of a character to
   compensate for the visual effects of changing a character's size. As
   a character gets smaller, the relative thickness of strokes, the size
   of serifs, the width of the character, the intercharacter spacing,
   and interline spacing should increase. Conversely, as a character
   gets larger, the relative thickness, widths, and spacing should
   decrease. Optical Scaling is used by Kingsley/ATF.

   Contrast this with linear scaling, in which all parts of a character
   get larger or smaller at the same rate, making large characters look
   wide and heavy (strokes are too thick, serifs are too big) while
   small characters look thin and weak. Linear scaling is used by Adobe,
   Altsys, Bitstream, and all other typeface manufacturers.

   The difference between linear scaling and Optical Scaling are clear,
   a difference even the untrained eye can see. The difference is
   particularly easy to see at high resolutions.

   Kerning

   As applied to PostScript fonts, kerning refers to kern pairs. A kern
   pair specifies two characters (e.g., A and V) and the distance to
   move the second character relative to the first. The typical use of a
   kern pair is to remove excessive space between a pair of characters.
   However, it may also be used to add space.

   How many kern pairs do you need? The answer depends on how well
   regular character spacing has been set and on the typeface itself.
   The better the default letterspacing has been set, the fewer kerning
   pairs are needed. In fact, an excessive number of kern pairs may be
   the artifact of a poor letterspacing job.

   The typeface itself has a lot to do with which characters may benefit
   from kerning. Just because one typeface has a kern pair does not mean
   the text typeface will need kerning for the same pair. Different
   typeface designs have very different kerning requirements.

   The moral to the story is: The number of kerning pairs is not a good
   quality indicator.

   PostScript clones

   There are currently several printer manufacturers on the market with
   PostScript clones. To be viable, a PostScript clone must comply with
   the `red book' (PS Language Reference Manual). The main problem the
   clones have is with fonts. Much of the font (and copy-protection)
   technology Adobe uses is undocumented.

   The eexec operator is not defined and Adobe protects its operations
   as a trade secret. Without the eexec operator Adobe fonts cannot be
   decrypted. There are many other operators like eexec, such as the
   internal BuildChar routine, that are required for proper operation of
   Adobe fonts, and these operators are also held as trade secrets.
   Without these operators, the Adobe font data cannot be interpreted.

   The clone problem can be approached from two directions. RIPS, a
   PostScript clone manufacturer, has reverse-engineered the eexec and
   other operators (including BuildChar and friends) and now sells a
   PostScript clone that is Adobe-compatible in all respects needed for
   proper interpretation of Adobe font data (Type 1 encrypted). Other
   companies are sure to follow. This is only important to users who
   have purchased or desire to purchase the Adobe/Linotype font library.

   The other way to solve the font technology problem is to implement
   your own. This is the route chosen by Altsys, Bitstream,
   Kingsley/ATF, and various other vendors. Some of the technologies
   used by these companies have been listed and compared. All these
   vendors use Type 3 unencrypted fonts, but the similarities end there.
   The technologies implemented from one company to the next vary in
   source of artwork, precision of digitization, availability and types
   of hints, Optical Scaling, storage requirements, and much more.

   Apple Royal (`sfnt') format and System 7

   Apple's new System 7.0 will support a new format of outline font that
   will allow high-quality characters of any size to be displayed on the
   screen. The new format (`sfnt') stores font outlines as B-spline
   curves along with programmed resolution hints. B-spline curves are
   faster to compute and easier to manipulate than the Bezier curves
   used in PostScript.

   Adobe is not going to support Apple's new format by converting the
   Adobe/Linotype library to B-spline format. There are two reasons for
   this: First, there is no support for font encryption (yes, the hooks
   are there, but nothing is implemented). Second, Adobe does not want
   to dilute PostScript and its font library. However, the Macintosh is
   too big a market to simply turn away from. Therefore, Adobe will
   provide its Font Manager to display its own fonts on the Mac screen.

   K/A will provide its entire library in Apple's B-spline format in
   addition to various PostScript formats. Users will be able to pick
   whatever format is most convenient.

   The Adobe font license

   When you license Adobe's font technology you get a `black box' that
   takes your font data in a prescribed format and turns it into Adobe's
   format with hints (suitable for use by the Type 1 BuildChar routine)
   and encrypted fonts for use by the eexec operator. No capability is
   provided to create or edit font data or screen fonts.

   The Kingsley/ATF font license

   When you license Kingsley/ATF's font technology you get a complete
   state-of-the-art font digitization system (ATF Type Designer I*),
   with output capabilities for supporting many operating systems and
   formats, resolution hinting, Optical Scaling, kerning editor,
   automatic screen font generation, and screen font editor. Included is
   a sophisticated end-user font utility. You also receive assistance in
   converting your current font data into the ATF format for editing.

   The Altsys font method

   Altsys sells a font digitization system called Fontographer without
   further license. The new version supports a limited version of the
   Nimbus-Q hinting system, and includes a kerning editor, output for
   the Macintosh, and a screen font editor.

   The FontStudio method

   Letraset has purchased the FRed font editor and should be releasing
   it soon. It will be sold without further license.

   The URW font method

   URW designed the Ikarus system about 15 years ago. Due to the
   normally small size of artwork and the cross-hair pointer used in the
   digitization process, the accuracy of outlines generated with this
   system suffers. This is the same system used to generate the Adobe
   font outlines. They are currently marketing the Nimbus-R hinting
   system.

   ATF Type Designer I and Optical Scaling are trademarks of
   Kingsley/ATF Type Corporation. PostScript is a trademark of Adobe
   Systems Incorporated. Apple and Macintosh are trademarks of Apple
   Computer, Inc.  Fontographer is a trademark of Altsys Corporation.
   Ikarus and Nimbus-R are trademarks of URW. FontStudio is a trademark
   of Esselte Pendaflex Corporation.

   *-[Unquote]---------------------------------------------------------*

2. Where can I get <> fonts.

   Before I go any farther, let me extol the virtues of the Archie servers.
   If you need to find something on the net, and you have any idea what it
   might be called, Archie is the place to go.  In North America, telnet to
   "archie.rutgers.edu" and login as "archie".  There are many other servers
   around the world, any Archie server can give you a list of other servers.
   There are better documents than this to describe Archie and you should be
   able to find them from the above starting point.  If you have trouble,
   feel free to ask norm <[e-mail]> (via Email please, no need to
   clutter comp.fonts with a query about Archie ;-).

   In addition to the telnet option, several archie clients exist including
   a very nice XArchie implementation.

   Adobe Type 1 Fonts in MS-DOS/Unix Format:

      ftp.cica.indiana.edu:/pub/pc/win3/fonts
      ftp.cica.indiana.edu:/pub/pc/win3/fonts/atm
      archive.umich.edu:/msdos/mswindows/fonts

   Adobe Type 1 Fonts in Mac Format:

      mac.archive.umich.edu:/mac/system.extensions/font/type1
      sumex-aim.stanford.edu:/info-mac/font

   Adobe Type 3 Fonts in Mac Format:

      mac.archive.umich.edu:/mac/system.extensions/font/type3

   TrueType fonts in MS-DOS Format:

      ftp.cica.indiana.edu:/pub/pc/win3/truetype

   TrueType fonts in Mac Format:

      mac.archive.umich.edu:/mac/system.extensions/font/truetype

   TeX PK/PXL/GF fonts:

      The TeX community has it's own support groups that can provide better
      answers to this question.  The canonical list of MetaFont fonts is
      posted occasionally to comp.text.tex.  The comp.text.tex newsgroup (or
      the Info-TeX mailing list, if you do not have access to news) are good
      places to start.  Email norm <[e-mail]> if you need more
      specific information.

   LaserJet bitmap fonts:

      wuarchive.wustl.edu:/pub/msdos/laser

      Also on other simtel20 mirrors...

   If you know of other archive sites (the above list is no where near
   complete) or other formats that are available on the net, please let us
   know.

   The sites above represent places where shareware and public domain fonts
   are available.  Many, many typefaces are not available in shareware form.
   And many shareware faces are less than adequate for a variety of reasons,
   particularly at small sizes.  It seems to be the consensus of the
   comp.fonts community that "you get what you pay for."  If you need a
   professional quality font, you should probably buy it from a
   professional.

   A list of font vendors (annotated with information about non-Roman
   alphabets) was contributed by Masumi Abe <[e-mail]>.   Masumi is
   Adobe's Manager of Typographic Marketing for Asia. [ed: as of 7/92]

   The list is quite long and it is posted separately.  It can be retrieved
   via anonymous ftp from /pub/norm/comp.fonts on ibis.cs.umass.edu.

3. Where can I get fonts for non-Roman alphabets.

   As mentioned above, the list of font vendors is annotated with
   information about non-Roman alphabets.  Commercially, Masumi
   <[e-mail]> suggests that Linguists' Software is the current [ed: as
   of 7/92] leading supplier of non-Roman fonts.

4. How can I convert my <> font to <> format?

   Conversion from one bitmapped format to another is not generally too
   difficult.  Conversion from one scalable format to another is very
   difficult.  Several commercial software packages claim to perform
   these tasks, but none has been favorably reviewed by the comp.fonts
   community.  ATech's AllType program, in particular, has had poor
   reviews [ed: as of 7/92].

   For specific conversions, check the platform specific parts of the
   FAQ.  Most of the conversions discussed require platform specific
   tools.

   Here is a summary of the conversions discussed (and the section in
   which they appear):

   From                       To                         Notes
   -------------------------  -------------------------  -------------
   Mac Type1 PostScript       PC Type1 PostScript        MS-DOS
   PC Type1 PostScript        Mac Type1 PostScript       Mac, commercial
   TrueType                   Type1 PostScript        }  No answer as
   Type1 PostScript           TrueType                }  of 7/92
   PC Type1 PostScript        TeX PK                     MS-DOS
   TeX PK                     HP LaserJet bitmaps        MS-DOS
   HP LaserJet bitmaps        TeX PK                     MS-DOS
   TrueType                   HP LaserJet bitmaps        MS-DOS, hack!!

5. Are fonts copyrightable?

   This topic is hotly debated at regular intervals on comp.fonts.
   Terry Carroll <[e-mail]> provides the following
   analysis of current [ed: as of 6/92] legislation and regulation
   regarding fonts and copyrights.  Members of the comp.fonts community
   are encouraged to submit other materials that add clarity to the
   issue.

   It has been pointed out that this section deals primarily font copyright
   issues relevant to the United States and that this situation is not
   universal.  For example, in many parts of Europe typeface designs are
   protectable.

   *-[Quote]-----------------------------------------------------------*

   First, the short answer: Typefaces are not copyrightable; bitmapped
   fonts are not copyrightable, but scalable fonts are copyrightable.
   Authorities for these conclusions follow.

   Before we get started, let's get some terminology down:

   A typeface is a set of letters, numbers, or other symbolic characters,
   whose forms are related by repeating design elements consistently
   applied in a notational system and are intended to be embodied in
   articles whose intrinsic utilitarian function is for use in composing
   text or other cognizable combinations of characters.

   A font is the computer file or program that is used to represent or
   create the typeface.

   Now, on to the legal authorities:

   Volume 37 of the Code of Federal Regulations specifies this about the
   copyrightability of typefaces:

   "The following are examples of works not subject to copyright and
   applications for registration of such works cannot be entertained: . . .
   typeface as typeface" 37 CFR 202.1(e).

   By the way, you won't find that in the most recent (7/1/91) edition of
   the CFR; the addition was enacted 2/21/92.  It'll be in the next
   edition, though.  It's described in the 2/21/92 edition of the Federal
   Register, page 6201 (57 FR 6201).  The change didn't actually change the
   law, it just clarified it, and codified existing Copyright Office
   policy.

   The regulation is in accordance with the House of Representatives report
   that accompanied the new copyright law, when it was passed in 1976:

   "The Committee has considered, but chosen to defer, the possibility of
   protecting the design of typefaces.  A 'typeface' can be defined as a
   set of letters, numbers, or other symbolic characters, whose forms are
   related by repeating design elements consistently applied in a
   notational system and are intended to be embodied in articles whose
   intrinsic utilitarian function is for use in composing text or other
   cognizable combinations of characters.  The Committee does not regard
   the design of typeface, as thus defined, to be a copyrightable
   'pictoral, graphic, or sculptural work' within the meaning of this bill
   and the application of the dividing line in section 101."  H. R. Rep.
   No.  94-1476, 94th Congress, 2d Session at 55 (1976), reprinted in 1978
   U.S. Cong. and Admin. News 5659, 5668.

   It's also in accordance with the one court case I know of that has
   considered the matter: Eltra Corp. V. Ringer, 579 F.2d 294, 208 USPQ 1
   (1978, C.A. 4, Va.).

   The Copyright Office holds that a bitmapped font is nothing more than a
   computerized representation of a typeface, and as such is not
   copyrightable:

   "The [September 29, 1988] Policy Decision [published at 53 FR 38110]
   based on the [October 10,] 1986 Notice of Inquiry [published at 51 FR
   36410] reiterated a number of previous registration decisions made by
   the [Copyright] Office.  First, under existing law, typeface as such is
   not registerable.  The Policy Decision then went on to state the
   Office's position that 'data that merely represents an electronic
   depiction of a particular typeface or individual letterform' [that is, a
   bitmapped font] is also not registerable."  57 FR 6201.

   However, scalable fonts are, in the opinion of the Copyright Office,
   computer programs, and as such are copyrightable:

   "... the Copyright Office is persuaded that creating scalable typefonts
   using already-digitized typeface represents a significant change in the
   industry since our previous [September 29, 1988] Policy Decision.  We
   are also persuaded that computer programs designed for generating
   typeface in conjunction with low resolution and other printing devices
   may involve original computer instructions entitled protection under the
   Copyright Act.  For example, the creation of scalable font output
   programs to produce harmonious fonts consisting of hundreds of
   characters typically involves many decisions in drafting the
   instructions that drive the printer.  The expression of these decisions
   is neither limited by the unprotectable shape of the letters nor
   functionally mandated.  This expression, assuming it meets the usual
   standard of authorship, is thus registerable as a computer program."  57
   FR 6202.

   *-[Unquote]---------------------------------------------------------*

6. File Formats / Font Formats / Ligatures / Standard Fonts / Glossary

6.1. File Formats

  Many different kinds of files are available on the net.  These files
  contain many different kinds of data for many different architectures.
  Frequently, the extension (trailing end) of a filename gives a good
  clue as to the format of its contents and the architecture that it was
  created on.

  In order to save space, most files on the net are compressed in one
  way or another.  Many compression/decompression programs exist on
  multiple architectures.

  Multiple files and directories are often combined into a single
  'archive' file.  Many archive formats perform compression
  automatically.

6.1.1. File Format Extensions

  .tar   Unix 'tape archive' format.  Tar files can contain multiple files
         and directories.  Unlike most archiving programs, tar files are
     held together in a wrapper but are not automatically compressed
     by tar.

  .Z     Unix 'compress' format.  Compression doesn't form a wrapper around
         multiple files, it simply compresses a single file.  As a result,
     you will frequently see files with the extension .tar.Z.  This
     implies that the files are compressed tar archives.

  .hqx   Macintosh 'BinHex' format.  In order to reliably transfer Mac files
         from one architecture to another, they are BinHex encoded.  This
     is actually an ascii file containing mostly hexadecimal digits.
     It is neither a compression program nor an archive wrapper.

  .sit   Macintosh 'Stuffit' archive.

  .cpt   Macintosh 'Compactor' archive.

         Like the .tar.Z format that is common among Unix archives, Macintosh
     archives frequently have the extensions .sit.hqx or .cpt.hqx
     indicating a BinHex'ed archive.

  .arc   PC 'arc' archive.  This is an older standard (in PC terms, at least)
         and has gone out of fashion.

  .zip   PC 'zip' archive.  This is the most common PC archive format today.

  .arj   PC 'arj' archive.

  .zoo   PC 'zoo' archive

  .lzh   PC 'lha/lharc' archive.

6.2. Font Formats

  Just as the are many, many archive formats, there are many different
  font formats.  The characteristics of some of these formats are
  discussed below.  Once again, the file extension may help you to
  determine the font type.  (On the Mac, the resource TYPE field is
  (probably) a better indicator).

  PostScript Type 1 Fonts:

    Postscript Type 1 fonts (Also called ATM (Adobe Type Manager) fonts,
    Type 1, and outline fonts) contains information, in outline form,
    that allows a postscript printer, or ATM to generate fonts of any
    size.  Most also contain hinting information which allows fonts to
    be rendered more readable at lower resolutions and small type sizes.

  PostScript Type 3 Fonts:

    Postscript type 3 fonts are an old outline font format that is not
    compatible with ATM.  Most developers have stopped using this format
    except in a few special cases, where special type 3 characteristics
    (pattern fills inside outlines, for example) have been used.

  TrueType Fonts:

    Truetype fonts are a new font format developed by Microsoft with
    Apple.  The rendering engine for this font is built into system 7
    and an init, the Truetype init, is available for system 6 (freeware
    from Apple).  It is also built into MS Windows v3.1.  Like
    PostScript Type 1 and Type 3 fonts, it is also an outline font
    format that allows both the screen, and printers, to scale fonts to
    display them in any size.

  Bitmap Fonts:

    Bitmap fonts contain (surprise) bitmaps of fonts in them.  This a
    picture of the font at a specific size that has been optimized to
    look good at that size. It cannot be scaled bigger without making it
    look horrendously ugly.  On the Macintosh, bitmap fonts also contain
    the kerning information for a font and must be installed with both
    type 1 and type 3 fonts.  Their presence also speeds the display of
    commonly used font sizes.

6.2.1. Font Format Extensions

  .afm   Adobe Type 1 metric information in 'ascii' format (human parsable)
  .bdf   Adobe's Bitmap Distribution Format.  This format can be converted
         to the platform specific binary files required by the local X Windows
     server.  This is a bitmap font format distributed in ASCII.
  .chr   Borland stroked font file
  .gf    TeX graphic font bitmap font file
  .mf    TeX MetaFont font file (text file of MetaFont commands)
  .pfa   Adobe Type 1 Postscript font in "ascii" format (PC/Unix)
         I believe that this format is suitable for directly downloading to
     your PostScript printer (someone correct me if I'm wrong ;-)
  .pfb   Adobe Type 1 PostScript font in "binary" format (PC/Unix)
         Note: this format is not suitable for downloading directly to your
     PostScript printer.  There are utilities for conversion between
     PFB and PFA (see the utilities section of the FAQ).
  .pfm   Printer font metric information in Windows format
  .pk    TeX packed bitmap font file
  .ps    Frequently, any PostScript file.  With respect to fonts, probably
         a Type3 font.  This designation is much less 'standard' than the
     others.
  .pxl   TeX pixel bitmap font file
  .sfl   LaserJet bitmapped softfont, landscape orientation
  .sfp   LaserJet bitmapped softfont, portrait orientation
  .sfs   LaserJet scalable softfont

6.3. Ligatures

   A ligature occurs where two or more letterforms are written or
   printed as a unit.  Generally, ligatures replace characters that
   occur next to each other when they share common components.
   Ligatures are a subset of a more general class of figures called
   "contextual forms."  Contextual forms describe the case where the
   particular shape of a letter depends on its context (surrounding
   letters, whether or not it's at the end of a line, etc.).

   One of the most common ligatures is "fi".  Since the dot above a
   lowercase 'I' interferes with the loop on the lowercase 'F', when 'f'
   and 'i' are printed next to each other, they are combined into a
   single figure with the dot absorbed into the 'f'.

   An example of a more general contextual form is the greek lowercase
   sigma.  When typesetting greek, the selection of which 'sigma' to use
   is determined by whether or not the letter occurs at the end of the
   word (i.e., the final position in the word).

   Amanda Walker <[e-mail]> provides the following discussion of
   ligatures:

   Ligatures were originally used by medieval scribes to conserve space
   and increase writing speed.  A 14th century manuscript, for example,
   will include hundreds of ligatures (this is also where "accents" came
   from).  Early typefaces used ligatures in order to emulate the
   appearance of hand-lettered manuscripts.  As typesetting became more
   automated, most of these ligatures fell out of common use.  It is
   only recently that computer based typesetting has encouraged people
   to start using them again (although 'fine art' printers have used
   them all along).  Generally, ligatures work best in typefaces which
   are derived from calligraphic letterforms.  Also useful are
   contextual forms, such as swash capitals, terminal characters, and so
   on.

   A good example of a computer typeface with a rich set of ligatures is
   Adobe Caslon (including Adobe Caslon Expert).  It includes:

       Upper case, lower case, small caps, lining numerals, oldstyle
       numerals, vulgar fractions, superior & inferior numerals,
       swash italic caps, ornaments, long s, and the following ligatures:

       ff fi fl ffi ffl Rp ct st Sh Si Sl SS St (where S=long s)

   [Ed: Perhaps a more common example is the Computer Modern Roman
   typeface that is provided with TeX. this family of fonts include the
   ff, fi, fl, ffi, and ffl ligatures which TeX automatically uses when
   it finds these letters juxtaposed in the text.]

   While there are an infinite number of possible ligatures, generally
   only the most common ones are actually provided.  In part, this is
   because the presence of too many alternate forms starts reducing
   legibility.  A case in point is Luxeuil Miniscule, a highly-ligatured
   medieval document hand which is completely illegible to the untrained
   eye (and none too legible to the trained eye, either :)).

   There is no "complete" set of ligatures.

6.4. Standard Laser Printer Fonts

  Postscript printers with 17 fonts have:

    Courier, Courier-Bold, Courier-BoldOblique, Courier-Oblique, Helvetica,
    Helvetica-Bold, Helvetica-BoldOblique, Helvetica-Narrow,
    Helvetica-Narrow-Bold, Helvetica-Narrow-BoldOblique,
    Helvetica-Narrow-Oblique, Helvetica-Oblique, Symbol, Times-Bold,
    Times-BoldItalic, Times-Italic, Times-Roman

  Postscript printers with 35 fonts have:

    All of the above, plus the following:

    ZapfChancery-MediumItalic, ZapfDingbats, AvantGarde-Book,
    AvantGarde-BookOblique, AvantGarde-Demi, AvantGarde-DemiOblique,
    Bookman-Demi, Bookman-DemiItalic, Bookman-Light, Bookman-LightItalic,
    NewCenturySchlbk-Bold, NewCenturySchlbk-BoldItalic,
    NewCenturySchlbk-Italic, NewCenturySchlbk-Roman, Palatino-Bold,
    Palatino-BoldItalic, Palatino-Italic, Palatino-Roman

  HP LaserJet printers (II, IIP)

    Courier 10, Courier 12, LinePrinter 16.66, ...

  HP LaserJet printers (III, IIIP)

    All of the above, plus the following:

    Scalable Times Roman, Scalable Univers

6.5. Glossary

   [ I ripped this right out of the manual I wrote for Sfware.  If you have
     comments, improvements, suggestions, please tell me... ]

   baseline

      The baseline is an imaginary line upon which each character rests.
      Characters that appear next to each other are (usually) lined up so
      that their baselines are on the same level.  Some characters extend
      below the baseline (``g'' and ``j'', for example) but most rest on
      it.

      More technically:

      The baseline is the invisible line around which character images are
      positioned.  A sequence of characters is usually aligned, when rendered,
      according to the baseline.  For example, an English 'A' sits on top of
      the baseline, while 'g' extends both above and below the baseline."

   bitmap

      A bitmap is an array of dots. If you imagine a sheet of graph paper
      with some squares colored in, a bitmap is a compact way of
      representing to the computer which squares are colored and which are
      not.

      In a bitmapped font, every character is represented as a pattern of
      dots in a bitmap. The dots are so small (300 or more dots-per-inch,
      usually) that they are indistinguishable on the printed page.

   character

      A character is an individual symbol in a font. The letter ``A'' is a
      character.  So is a period.  All of the printed symbols that can
      appear in a font are characters.  They can also be called glyphs.

      More technically: