[OpenJDK 2D-Dev] RFR: 8143177: Integrate harfbuzz opentype layout engine per JEP 258

Sergey Bylokhov Sergey.Bylokhov at oracle.com
Sun Nov 22 12:33:41 UTC 2015

On 18.11.15 18:09, Sergey Bylokhov wrote:
> Hi, Phil.
> Not an expert here, just a few notes:
>   - Copyright is missing: hb-jdk-font.cc, hb-jdk.h
>   - HBShaper.c: Do we need a code at 268? probably we can add some todo
> or remove it?

same comments about 8143177.2, or it is intended?

> On 18.11.15 3:05, Philip Race wrote:
>> Webrev : http://cr.openjdk.java.net/~prr/8143177/
>> Bug : https://bugs.openjdk.java.net/browse/JDK-8143177
>> This webrev contains the changes accumulated in the harfbuzz project
>> forest
>> that migrate JDK from using ICU for opentype font layout to harfbuzz for
>> the same.
>> The change does not introduce API. It is mostly adding the harfbuzz
>> library.
>> The ICU library remains there but is no longer the default.
>> Eventually (not necessarily in 9) it may be removed once we are
>> comfortable
>> with harfbuzz.
>> You may select ICU by using -Dsun.font.layoutengine=icu
>> You may see which layout engine is in use by using
>> -Dsun.font.layoutengine.verbose=true
>> it will print either "Using harfbuzz", or "Using ICU".
>> The change has no impact on typical Latin script rendering but is a big
>> advance
>> for complex scripts and also applies if you select kerning or ligatures
>> for Latin.
>> However the latter is only detectable if the font implements support for
>> these.
>> By "big advance" I mean that ICU has not been updated to recognise
>> recent opentype features.
>> So harfbuzz should fix a number of things but unexpected changes that
>> look wrong
>> should be reported so we can investigate.
>> To use harfbuzz we invoke its shaper and we provide a way to get jdk
>> font information.
>> This means that we do not need a different layer depending on whether
>> freetype or t2k
>> is used. It also enables some caching in the JDK font layer.
>> On macosx harfbuzz does not natively read the AAT tables but will invoke
>> CoreText.
>> This does mean that an AAT font installed on Linux would not be
>> processed but
>> this is not a significant issue since AAT fonts are not found other than
>> on macosx.
>> The majority of the files in the webrev are harfbuzz itself, changed
>> only to comply
>> with JDK whitespace rules. Reviewers should probably concentrate on all
>> of the rest.
>> I've listed it so that all those files are at the beginning and you can
>> ignore all those
>> that follow that are in the "harfbuzz" directory.
>> The harfbuzz version used here is 1.0.6 which is the latest source
>> release (at the time of writing).
>> We expect to update this to keep reasonably current.
>> I would like to push this in on Friday, but at the very latest Monday
>> because of the
>> upcoming Feature Complete date so there are a couple of days to make
>> small
>> tweaks for serious problems but there will be plenty of time after
>> integration to fix
>> remaining problems.
>> -phil.

Best regards, Sergey.

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