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

Phil Race philip.race at oracle.com
Fri Nov 20 23:09:59 UTC 2015

On 11/19/2015 12:51 PM, Steven Loomis wrote:
> I have reviewed the non-harfbuzz portion (outside of the /harfbuzz/ 
> directory) and it looks good so far.

Thanks. The harfbuzz code itself probably does not need careful 
reviewing as it is just
the upstream harfbuzz. I have updated it to remove the gpl text from the 
hb src files but
I haven't changed anything else :- 

Any takers to be 2nd reviewer ?


> -s
> On 11/17/2015 4:05 PM, 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.

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