The FreeType Project - Bugs: bug #54589, Some Vertical Line characters of...
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bug #54589: Some Vertical Line characters of Japanese fonts disappeared without anti-alias
Submitter: | Toshio Nakamura <tnakamura> | ||
Submitted: | Wed 29 Aug 2018 10:12:15 AM UTC | ||
Severity: | 3 - Normal | Item Group: | Incorrect behaviour |
Status: | Fixed | Privacy: | Public |
Assigned to: | wl | Open/Closed: | Closed |
Planned Release: | 2.10.0 |
Jump to the original submission
Tue 19 May 2020 06:06:54 PM UTC, comment #14: |
Alexei Podtelezhnikov <podtelez> |
Thu 15 Nov 2018 08:05:41 PM UTC, comment #13: You seem to have fixed Vertical_Sweep_Span, but horizontal lines exactly aligned with pixel centers are still dropping out.
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Alexei Podtelezhnikov <podtelez> |
Tue 25 Sep 2018 06:03:52 AM UTC, comment #12: I see. Thank you for your reply. |
Toshio Nakamura <tnakamura> |
Tue 25 Sep 2018 05:38:28 AM UTC, comment #11: I can only repeat: for outline fonts only FreeType's TrueType font driver has proper monochrome hinting support (provided the font contains bytecode for B/W hinting). `NotoSerifCJKjp-Regular.otf', as the extention `.otf' already indicates, is not a TTF! It's a CFF and thus can't be rendered well as B/W at small sizes.
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Werner LEMBERG <wl> |
Mon 24 Sep 2018 02:21:44 PM UTC, comment #10: Thank you so much for fixing our problem.
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Toshio Nakamura <tnakamura> |
Fri 21 Sep 2018 09:11:23 AM UTC, comment #9: And the B/W rasterizer is now fixed, too.
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Werner LEMBERG <wl> |
Fri 21 Sep 2018 02:45:53 AM UTC, comment #8: ft_glyphslot_preset_bitmap should be fixed. |
Alexei Podtelezhnikov <podtelez> |
Wed 19 Sep 2018 10:25:38 AM UTC, comment #7: I've now taken a closer look – thanks for being pertinent :-)
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Werner LEMBERG <wl> |
Wed 19 Sep 2018 03:33:29 AM UTC, comment #6: Thank you for your reply. I understood that.
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Toshio Nakamura <tnakamura> |
Tue 18 Sep 2018 01:24:14 PM UTC, comment #5: I am aware of the issue in the dropout control code. I cannot commit to a time line to fix it however. |
Alexei Podtelezhnikov <podtelez> |
Tue 18 Sep 2018 12:59:41 PM UTC, comment #4: I found some bigger fonts also had this problem.
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Toshio Nakamura <tnakamura> |
Sun 16 Sep 2018 05:33:18 AM UTC, comment #3: I've just added the following to `freetype.h':
Note that for outline fonts only the TrueType font driver has proper monochrome hinting support, provided the TTFs contain hints for B/W rendering (which most fonts no longer provide). If these conditions are not met it is very likely that you get ugly results at smaller sizes. Closing as `won't fix'. If you need B/W rendering of CJK fonts at small sizes you should use a TTF that contains B/W hints (for example, the famous `mingli.ttf' (from 1994), or a font that contains embedded bitmaps for the requested ppem values. |
Werner LEMBERG <wl> |
Thu 13 Sep 2018 10:44:09 AM UTC, comment #2: This problem was found by Java application. Its AWT components are working without anti-aliasing. And, there are a lot of legacy applications on active, I think.
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Toshio Nakamura <tnakamura> |
Thu 30 Aug 2018 03:46:31 PM UTC, comment #1: This is a flaw in dropout control of monochrome rasterizer when the stem edges precisely align with pixel centers. Perhaps there is a strict instead of non-strict inequality bug somewhere. We lack motivation to track it down because the monochrome rasterizer is not very popular these days.
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Alexei Podtelezhnikov <podtelez> |
Wed 29 Aug 2018 10:12:15 AM UTC, original submission:
I could recreate the problem with demo program.
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Toshio Nakamura <tnakamura> |
Depends on the following items: None found
Items that depend on this one: None found
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Follow 11 latest changes.
Date | Changed by | Updated Field | Previous Value | => | Replaced by |
---|---|---|---|---|---|
2018-09-21 | wl | Status | Confirmed | Fixed | |
Open/Closed | Open | Closed | |||
Planned Release | None | 2.10.0 | |||
2018-09-19 | wl | Status | Wont Fix | Confirmed | |
Open/Closed | Closed | Open | |||
2018-09-16 | wl | Status | None | Wont Fix | |
Assigned to | None | wl | |||
Open/Closed | Open | Closed | |||
2018-08-29 | tnakamura | Attached File | - | Added NotoImage.png, #44894 | |
Attached File | - | Added VLGothicImage.png, #44895 | |||
Carbon-Copy | - | Added tnakamura |
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Corresponding source code
Werner,
You fixed this bug for vertical stems only, but it remains in horizontal stems. I wonder if the fix is easy to apply there as well. Then we can possibly close bug 58373.
Thank you.