[OpenJDK 2D-Dev] RFR: 8190280 [macos] Font2DTest demo started failing for Arabic range from JDK 8 u162 b01 on Mac

[Prahalad Kumar Narayanan]

Hello Phil

The change looks good.

Thanks
Have a good day

Prahalad N.

-----Original Message-----
From: Philip Race 
Sent: Wednesday, November 01, 2017 11:40 PM
To: 2d-dev
Subject: [OpenJDK 2D-Dev] RFR: 8190280 [macos] Font2DTest demo started failing for Arabic range from JDK 8 u162 b01 on Mac

Bug: https://bugs.openjdk.java.net/browse/JDK-8190280
Webrev: http://cr.openjdk.java.net/~prr/8190280/

This is a JDK8 version of the bug
https://bugs.openjdk.java.net/browse/JDK-8172967
which affected harfbuzz in JDK 9

It is triggered by a couple of things but mainly that the Mac font code sometimes sets a glyphid to be the negation of the unicode to tell a special fallback path that the glyphid is not actually supported by the font and low-level rendering code should supply a fall back.

The essence of the fix here is that in the ICU code we reject negative glyph ids and treat them as missing.

The check for AIOBE in CompositeStrike is just an extra safe guard.

-phil