BUGS

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Author : Werner Lemberg
Date : 2001-12-07 21:56:32
Hash : e9e130c0
Message : Formatting.
docs/BUGS
List of known FreeType 2 Bugs
-----------------------------

"Identifier" is a string to uniquely identify the bug.  A more detailed
description of the bug is found below the table of opened bugs.

"Date" is the date when the bug was first reported or entered in this
document.  Dates are in _European_ format, i.e day/month/year.

"Opened By" is the name of the person who first spotted the bug. Note that
we can use abbreviations here, like:

  "David" for David Turner
  "Werner" for Werner Lemberg
  etc.

"Reproduceable" indicates whether the bug could be reproduced by the
development team or not (it can be specific to a given platform), whether it
always happens, or only sporadically, etc.



I. Opened bugs
==============


Identifier                 Date       Opened by                Reproduceable
------------------------------------------------------------------------------
NO-CID-CMAPS            13-09-2001     David                     always
AUTOHINT-NO-SBITS       13-09-2001     David                     always
BAD-TT-RENDERING        12-09-2001     Paul Pedriana             ?
BAD-THIN-LINES          13-09-2001     David                     ?
NOT-WINDOWS-METRICS     07-10-2001     David                     always
ADVANCED-COMPOSITES     25-10-2001     George Williams           always

--------------------END-OF-OPENED-BUGS-TABLE----------------------------------



II. Table of closed bugs
========================


Identifier                Date         Closed by                Closure date
------------------------------------------------------------------------------
BAD-TTNAMEID.H          12-09-2001     Antoine                   N/A
BAD-T1-CHARMAP          15-06-2001     David                     2.0.5
BAD-UNIXXX-NAMES        30-07-2001     David                     2.0.5
GLYPH_TO_BITMAP-BUG     05-12-2001     David                     05-12-2001

--------------------END-OF-CLOSED-BUGS-TABLE----------------------------------



III. Bug descriptions
=====================


NO-CID-CMAPS

  Not exactly a bug, but the CFF font driver doesn't build a Unicode charmap
  from the contents of font files, which prevents efficiently using fonts in
  this format.


BAD-TTNAMEID.H

  The file "ttnameid.h" contains various constant macro definitions
  corresponding to important values defined by the TrueType specification.

  Joe Man <trmetal@yahoo.com.hk> reports that:

    According to the information from TrueType v1.66:

      Platform ID = 3 (Microsoft)
      the Encoding ID of GB2312 = 4
      the Encoding ID of big5 = 3

    However, I have found that in ttnameid.h:

      TT_MS_ID_GB2312 = 3
      TT_MS_ID_BIG_5 = 4

    Which one is correct?

  Antoine replied that this was a bug in the TT 1.66 specification, and that
  FreeType followed the most recent TrueType/OpenType specification here!


AUTOHINT-SBITS

  When trying to load a glyph, with the auto-hinter activated (i.e., when
  using FT_LOAD_FORCE_AUTOHINT, or when the font driver doesn't provide its
  own hinter), embedded bitmaps are _never_ loaded, unlike the default
  behaviour described by the API specification.

  This seems to be a bug in FT_Load_Glyph(), but there is no way to solve it
  efficiently without making a few important internal changes to the
  library's design (more importantly, to the font driver interface).


BAD-TT-RENDERING

  According to Paul Pedriana <PPedriana@maxis.com>, there is a rather
  important difference between the rendering of TrueType-hinted glyphs of
  current FT2 and old betas.

  Tests and comparisons show a _major_ discrepancy of monochrome truetype
  bytecode-hinted glyphs!  Something seems to be really broken here!


BAD-THIN-LINES

  It seems that the anti-aliased renderer in FreeType has problems rendering
  extremely thin straight lines correctly, at least when using the
  FT_Outline_Render() function.


NOT-WINDOWS-METRICS

  FreeType doesn't always return the same metrics as Windows for ascender,
  descender, and text height, depending on character pixel sizes.  A lot of
  testing on Windows is needed to debug this properly.  It might be due to a
  rounding bug when computing the "x_scale" and "y_scale" values.


BAD-T1-CHARMAP

  Type1 driver doesn't read "cacute" and "lslash" characters from iso8859-2
  charset.  Those characters are mapped as MAC-one in glnames.py, so they
  cannot be shown in Adobe Type1 fonts.

  (This was due to a bug in the "glnames.py" script used to generate the
  table of glyph names in 'src/psaux/pstables.h'.)


BAD-UNIXXX-NAMES

  Glyph names like uniXXXX are not recognized as they should be.  It seems
  that code in psmodule.c for uniXXXX glyph names was never tested.  The
  patch is very simple.
  
  (A simple bug that was left un-noticed due to the fact that I don't have
  any Postscript font that use this convention, unfortunately.)


ADVANCED-COMPOSITES

  Provided by George Williams <pfaedit@users.sourceforge.net>:

    I notice that truetype/ttgload.c only supports Apple's definition of
    offsets for composite glyphs.  Apple and Microsoft behave differently if
    there is a scale factor.  OpenType defines some bits to disambiguate.
    
    (A problem in both 2.0.4 and 2.0.5.)
    
    Apple says (http://fonts.apple.com/TTRefMan/RM06/Chap6glyf.html) that if
    flags&ARGS_ARE_XY is set then the offsets should be scaled by the scale
    factors (as you have done), but they also say something very cryptic
    about what happens when the component is rotated at 45
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