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Issue 654563 link

Starred by 4 users
Status: Assigned
Owner:
js...@chromium.org
Cc:
derat@chromium.org
bunge...@chromium.org
drott@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 3
Type: Bug

Blocking:
issue 824150



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Tune/adjust FreeType rendering parameters

Project Member Reported by js...@chromium.org, Oct 10 2016 
In bug 646635, FreeType was updated to 2.7 which introduced a new 'hinting' mode and made it the default. 

To avoid an unexpected change in a 54 branch, I turned off that explicitly. 

We need to evaluate and consider turning it on. 

Moreover, now that CFF and Truetype renderer can support 'horizontal stem only hinting' even with built-in hinting, we also have to experiment with it for Roboto and Noto CJK. 

Going to autohint is also an option, but we need to be careful. See  

https://github.com/googlei18n/noto-fonts/issues/750#issuecomment-251034599

BTW, not everybody likes a new default hinting mode in FreeType 2.7. See  bug 649362

Comment 1 by js...@chromium.org, Oct 10 2016

Cc: bunge...@chromium.org
> To avoid an unexpected change in a 54 branch, I turned off that explicitly. 

To be clear, it's turned off only on Chrome OS. (see 
https://chromium.googlesource.com/chromium/src.git/+/7a8ceafdc9b7dd4d7050a1368da4ba9db3d4bf97 ). 

Android Chrome has it enabled, but Android Chrome wouldn't usually be affected by it much.

Comment 2 by js...@chromium.org, Oct 10 2016 

One more tuning parameter (there's a bug already on this) for CFF fonts is stem-darkening. It's ON at the moment.

Comment 3 by js...@chromium.org, Nov 8 2017 

FreeType 2.8.1 now has a new 'rendering' mode called 'Harmony' when FT_CONFIG_OPTION_SUBPIXEL_RENDERING is undefined. Currently, it is defined, but we may consider undefining to get a new behavior when subpixel rendering is on (low res). 

Below is an excerpt from ChangeLog:

        This is a new technology for LCD-optimized rendering. It capitalizes
        on the fact that each color channel grid is shifted by a third of a
        pixel.  Therefore it is logical to render 3 separate monochrome
        bitmaps shifting the outline by 1/3 pixel, and then combine them.
        Importantly, the resulting output does not require additional LCD
        filtering.

        * src/smooth/ftsmooth.c (ft_smooth_render_generic)
        [!FT_CONFIG_OPTION_SUBPIXEL_RENDERING]: Implement new LCD-optimized
        rendering.

Comment 4 by derat@chromium.org, Nov 8 2017

Summary: Tune/adjust FreeType rendering parameters (was: Tune/adjust rendering parameters )

Comment 5 by agoode@chromium.org, Nov 8 2017 

It would be interesting to see if this helps with  issue #740385 .

Comment 6 by agoode@chromium.org, Mar 21 2018

Blocking: 824150

Comment 7 by zalcorn@chromium.org, Sep 28 

Triage nag: This Chrome OS bug has an owner but no component. Please add a component so that this can be tracked by the relevant team.

Comment 8 by weifangsun@chromium.org, Nov 8 

<UI triage> Bug owners, please add the appropriate component to your bug. Thanks!

Comment 9 by drott@chromium.org, Nov 9

Components: UI Blink>Fonts
►

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