bugThe FreeType Project - Bugs: bug #23762, gaps in diagonals

 
 

bug #23762: gaps in diagonals

Submitted by:  Andrey V. Panov <panov>
Submitted on:  Fri 04 Jul 2008 01:24:20 AM UTC  
 
Severity: 3 - NormalItem Group: None
Status: FixedPrivacy: Public
Assigned to: Werner LEMBERG <wl>Open/Closed: Closed
Planned Release: 2.3.8

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Fri 11 Jul 2008 11:37:44 AM UTC, comment #5:

yes

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Fri 11 Jul 2008 04:07:00 AM UTC, comment #4:

> Previous versions of FreeType always used mode 5.


Is it:

"- The TrueType bytecode interpreter now passes the dropout mode to
the B&W rasterizer. This greatly increases the output for small
ppem values of many fonts like `pala.ttf'."?

Andrey V. Panov <panov>
Mon 07 Jul 2008 07:18:59 AM UTC, comment #3:

FreeType is right, at least for letter `V' at 12ppem (I haven't investigated the other cases): You don't have activated any dropout control, this is, your code doesn't call SCANTYPE and thus mode 2 (no dropout control) is in use. Previous versions of FreeType always used mode 5.

Counting the rows from the bottom, the left span in the third row has horizontal coordinates 3.5283203125 and 4.498046875 – this is 2077 and 3070 units in FreeType's rasterizer; the pixel centers are at 2048 and 3072 units, respectively. As you can see, neither pixel center 3.5 nor pixel center 4.5 is included, thus no pixel is switched on.

Regarding libtool: Your version is too old. Please read README.CVS for more information.

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Mon 07 Jul 2008 03:53:15 AM UTC, comment #2:

Still "V" has gaps at 6, 7, 10 and 12 ppem, "v" at 14, 15 ppem, "W" at 9, 12 ppem, parenthesis at 13 ppem and below, etc. All the glyphs were displayed continouosly by freetype 2.3.5 and I spent a lot of time on adjusting instructions of the font for freetype.

By the way running autogen.sh fails:

running `libtoolize --force --copy --install'
libtoolize: unrecognized option `--install'
Try `libtoolize --help' for more information.
error while running `libtoolize --force --copy --install'

with libtool 1.5.24. Which version should be used?

Andrey V. Panov <panov>
Fri 04 Jul 2008 07:28:20 AM UTC, comment #1:

Fixed in CVS. Please test.

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Fri 04 Jul 2008 01:24:20 AM UTC, original submission:

Freetype 2.3.7 displays gaps in diagonals when it utilizes tt bytecode interpreter in monochrome mode at small sizes. Freetype 2.3.5 displays the same diagonals continously. To make a comparison I attach two screenshots of ff bytecode debugger with both versions of freetype and the font. Font2DTest from java shows the diagonals unbroken.

Andrey V. Panov <panov>

 

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

Attach File(s):
   
   
Comment:
   

Attached Files
file #15993:  V_16ppem_ft235.png added by panov (14KiB - image/png - Screenshots of ff bytecode debugger with "V" from Edrip-Regular.ttf at 16 ppem)
file #15994:  Edrip-Regular.ttf added by panov (56KiB - application/x-font-ttf - Screenshots of ff bytecode debugger with "V" from Edrip-Regular.ttf at 16 ppem)
file #15995:  V_16ppem_ft237.png added by panov (13KiB - image/png - Screenshots of ff bytecode debugger with "V" from Edrip-Regular.ttf at 16 ppem)

 

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 panov (Submitted the item)
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    Follow 7 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Fri 04 Jul 2008 07:30:16 AM UTCwlStatusNone=>Fixed
    Fri 04 Jul 2008 07:29:58 AM UTCwlAssigned toNone=>wl
      Open/ClosedOpen=>Closed
      Planned ReleaseNone=>2.3.8
    Fri 04 Jul 2008 01:24:20 AM UTCpanovAttached File-=>Added V_16ppem_ft235.png, #15993
      Attached File-=>Added Edrip-Regular.ttf, #15994
      Attached File-=>Added V_16ppem_ft237.png, #15995

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