bugThe FreeType Project - Bugs: bug #23310, Incorrect image of one letter with...

 
 

bug #23310: Incorrect image of one letter with TT_CONFIG_OPTION_BYTECODE_INTERPRETER

Submitted by:  Alexander Morozov <amorozov>
Submitted on:  Wed 21 May 2008 09:39:11 AM UTC  
 
Severity: 3 - NormalItem Group: Incorrect behaviour
Status: FixedPrivacy: Public
Assigned to: David Turner <freetype>Open/Closed: Closed
Planned Release: 2.3.7

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Sun 22 Jun 2008 02:07:33 PM UTC, comment #10:

Fixed in the CVS. Please test.

Werner LEMBERG <wl>
Project Administrator
Mon 09 Jun 2008 01:01:38 PM UTC, comment #9:

Thanks a lot! This image is really helpful.

Werner LEMBERG <wl>
Project Administrator
Mon 09 Jun 2008 10:12:02 AM UTC, comment #8:

'0' is in the left column

(file #15820)

Alexander Morozov <amorozov>
Sun 08 Jun 2008 09:50:01 AM UTC, comment #7:

Could you please create an image similar to short_i_2.PNG using the attached font (displaying five variants of the short_i, and which are defined as glyphs for the digits 0, 1, 2, 4, and 5)?

I want to know whether setting different dropout modes has any influence on the rendering result on Windows.

(file #15814)

Werner LEMBERG <wl>
Project Administrator
Mon 26 May 2008 09:48:06 PM UTC, comment #6:

It seems that this is a rasterizer problem: At least a FontForge debugging session shows that the drop-out mode 4 (as specified for this glyph) isn't obeyed, causing stubs and incorrectly set pixels for 11 and 13 ppem.

I'm assigning this again to David :-)

Werner LEMBERG <wl>
Project Administrator
Mon 26 May 2008 10:33:09 AM UTC, comment #5:

I use just this version of the font.

Alexander Morozov <amorozov>
Mon 26 May 2008 10:03:34 AM UTC, comment #4:

I feared something like this. :-(

Just to be sure: which version of micross.ttf are you using? Mine is 1.41 (460728 bytes) -- in case you have a different one please send it to me privately for further examination.

Werner LEMBERG <wl>
Project Administrator
Mon 26 May 2008 08:58:36 AM UTC, comment #3:

Thank you. Now U+0439 looks better. But I do not see any features in the upper right of this symbol on Windows.

(file #15734)

Alexander Morozov <amorozov>
Sun 25 May 2008 01:01:38 PM UTC, comment #2:

This is fixed in the current CVS, please test. Note that the distortions of the base glyph of U+0439 in the upper right at 11 and 13ppem are caused by explicit delta instructions. Could you check on Windows whether the hinting results are the same?

Werner LEMBERG <wl>
Project Administrator
Thu 22 May 2008 06:26:49 AM UTC, comment #1:

Thanks for the demo program, but the problem is reproducable with ftview (even from the CVS) directly by saying

ftview -f 1081 -e unic 13 micross.ttf

a similar defect for this glyph can be seen at 11 pixels. I think it's the accent which causes the problem; U+045E has similar problems.

In general, this font causes great problems with FreeType; for example, at 13 pixels, U+0457 loses it's diaeresis completely.

At 17, 20, 23, and 40(!) pixels, the base letter of U+0457 is shifted to the right. Similar problems exist for U+0451.

BTW, I've tested with micross.ttf version 1.41.

David, please have a look!

Werner LEMBERG <wl>
Project Administrator
Wed 21 May 2008 09:39:11 AM UTC, original submission:

There is a problem with cyrillic small letter short i (U+0439) from micross.ttf (font from Windows XP) if freetype is built with CFLAGS=-DTT_CONFIG_OPTION_BYTECODE_INTERPRETER. The bug can be seen with FT_Set_Pixel_Sizes(face, 0, 13) (only with 13, not 12 or 14).

I attached screenshot and test program which demonstrates the problem (it shows letter bitmap badly but the bug can be seen).

Alexander Morozov <amorozov>

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):
   
   
Comment:
   

Attached Files
file #15820:  01245_winxp.png added by amorozov (3KiB - image/png)
file #15814:  micross-cyrillic-i.ttf added by wl (6KiB - application/x-font-ttf)
file #15734:  short_i_2.PNG added by amorozov (2KiB - image/png)
file #15689:  micross_bug.png added by amorozov (473B - image/png)
file #15690:  mytest.c added by amorozov (6KiB - application/octet-stream)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by wl (Posted a comment)
  • -unavailable- added by amorozov (Submitted the item)
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    Follow 24 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 22 Jun 2008 02:07:33 PM UTCwlStatusConfirmed=>Fixed
      Open/ClosedOpen=>Closed
      Planned ReleaseNone=>2.3.7
    Mon 09 Jun 2008 01:01:38 PM UTCwlStatusNeed Info=>Confirmed
    Mon 09 Jun 2008 10:12:01 AM UTCamorozovAttached File-=>Added 01245_winxp.png, #15820
    Sun 08 Jun 2008 09:50:01 AM UTCwlAttached File-=>Added micross-cyrillic-i.ttf, #15814
      StatusConfirmed=>Need Info
    Mon 26 May 2008 09:48:06 PM UTCwlStatusNeed Info=>Confirmed
      Assigned towl=>freetype
      Open/ClosedClosed=>Open
      Planned Release2.3.6=>None
    Mon 26 May 2008 10:03:34 AM UTCwlSeverity4 - Important=>3 - Normal
      StatusFixed=>Need Info
    Mon 26 May 2008 08:58:36 AM UTCamorozovAttached File-=>Added short_i_2.PNG, #15734
    Sun 25 May 2008 01:01:38 PM UTCwlStatusConfirmed=>Fixed
      Assigned tofreetype=>wl
      Open/ClosedOpen=>Closed
      Planned ReleaseNone=>2.3.6
    Thu 22 May 2008 06:26:49 AM UTCwlSeverity3 - Normal=>4 - Important
      Item GroupNone=>Incorrect behaviour
      StatusNone=>Confirmed
      Assigned toNone=>freetype
    Wed 21 May 2008 09:39:11 AM UTCamorozovAttached File-=>Added micross_bug.png, #15689
      Attached File-=>Added mytest.c, #15690

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