Re: [Devel] bug with MSung-Light-Acro

[Edward G.J. Lee]

Hello,

On Fri, Dec 21, 2001, David Turner wrote:
> Hello Edward,
> 
> > On Thu, Dec 20, 2001, Werner LEMBERG wrote:
> > >
> > > I've found an interesting bug in the font MSung-Light-Acro (CJK
> > > extension for Acroread; copyrighted 1998; I think I have version
> > > 3.001; size 6665200 Bytes).
> > >
> > > Using `ftview -f 2027 48 MSung-Light-Acro', look at glyph 2027.  It is
> > > displayed two times!  Reducing the size, the doublette vanishes.
> > > Switching AA off, you even get corrupted glyph images while zooming
> > > in...
> > 
> >   If I display via pfaedit or old version ftview(use CVS libfreetype),
> >   CNS1_2027 display one time only.
> > 
> >   Maybe it's not the problem of MSung-Light-Acro?
> >
> 
> It's definitely a problem with the library. I just looked at the code
> for ftview, and the function "get_glyph_bitmap" (in ftcommon.i) didn't
> check the error result of FT_Glyph_ToBitmap at all..

  This will help me to read the source code. Thanks for explainning.:)

> The "double" glyph could come from having glyph 2028 not being properly
> rendered (for a yet-to-be-determined reason), and the code using a dangling
> pointer to a previously rendered glyph (i.e. 2027). I wouldn't be surprised
> if the garbage that appears was due to heap allocated data accessed through
> the pointer, overwriting freed memory..
> 
> It's just an hypothesis but it's the best I can come with for now. Does
> someone knows where to find this font, __please__ (and do not send it to
> me via e-mail)..

  ftp://ftp.adobe.com/pub/adobe/acrobatreader/unix/4.x/chtfont.tar.gz

> I've added error checks to "ftview", could someone test the new code to
> see if the doublet and garbage still appear ??

  Thanks.

  This time miss CNS1_2028, behind the 2027 is 2029. Need ignore hinting
  (press h)to display correctly(Hit h then 2028 come out).


-- 
Warm Regards,
Edward G.J. Lee