bugThe FreeType Project - Bugs: bug #29017, MIRP instruction under ROFF

 
 

bug #29017: MIRP instruction under ROFF

Submitted by:  Andrey V. Panov <panov>
Submitted on:  Sat 27 Feb 2010 12:47:35 AM UTC  
 
Severity: 3 - NormalItem Group: Incorrect behaviour
Status: InvalidPrivacy: Public
Assigned to: Werner LEMBERG <wl>Open/Closed: Closed
Planned Release: None

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Tue 02 Mar 2010 06:26:08 AM UTC, comment #3:

OK. I'm marking this report as invalid.

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Tue 02 Mar 2010 05:38:20 AM UTC, comment #2:

Ok, it seems you are right.

Andrey V. Panov <panov>
Sat 27 Feb 2010 08:12:08 AM UTC, comment #1:

I think FreeType does it right, and the problem has nothing to do with rounding (which FreeType does correctly, BTW). For the MIRP instruction, the distance between the reference point and point 7 is measured along the dual_projection_vector (see explanation in SDPVTL), and this vector uses coordinates before grid-fitting takes place.

And indeed, using raw coordinates, the cut-in value does not allow the displacement.

Perhaps the documentation in the FontForge's instruction gloss window should be improved.

BTW, have you compared the result with the MS rasterizer? Is there a difference?

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Sat 27 Feb 2010 12:47:35 AM UTC, original submission:

In instructions of "afii10033" (П) at 19 ppem and antialiasing MIRP instruction moving point No. 7 against No. 1 (line 87 in fontforge's tt debugger) should move point No. 7 to x=10.81 pixels, but freetype moves it to x=12.17 pixels. The round state is set to "off", cvt cut in (1.06px) allows this displacement. According to specs from MS site (ttinst2.doc) "The c Boolean above controls both rounding and the use of Control Value Table entries. If you would like the meaning of this Boolean to specify only whether or not the MIRP[ ] instruction should look at the control_value_cut_in, use the ROFF[ ] instruction to turn off rounding. In this manner, it is possible to specify rounding off and no cut_in."

After setting this value to 0 as is done in "H" freetype moves the point to right position using control value No. 58.

Andrey V. Panov <panov>

 

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Attach File(s):
   
   
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Attached Files
file #19806:  Istok-Regular.ttf added by panov (173KiB - application/x-font-ttf - test font)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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  • -unavailable- added by wl (Posted a comment)
  • -unavailable- added by panov (Submitted the item)
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    Follow 5 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Tue 02 Mar 2010 06:26:08 AM UTCwlStatusNeed Info=>Invalid
      Open/ClosedOpen=>Closed
    Sat 27 Feb 2010 08:12:08 AM UTCwlStatusNone=>Need Info
      Assigned toNone=>wl
    Sat 27 Feb 2010 12:47:35 AM UTCpanovAttached File-=>Added Istok-Regular.ttf, #19806

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