[OpenJDK 2D-Dev] [11u] java/awt/FontMetrics/MaxAdvanceIsMax.java test failure (was: [11u] RFR 8210782: Upgrade HarfBuzz to the latest 2.3.1)

[Lindenmaier, Goetz]

Hi,

that's a good point.
First, I will check whether the bundled freetype fixes the issue.
Then, I can have a look how to adapt the test, some whitebox
functionality maybe.

Best regards,
  Goetz.

> -----Original Message-----
> From: jdk-updates-dev <jdk-updates-dev-bounces at openjdk.java.net> On
> Behalf Of Andrew John Hughes
> Sent: Mittwoch, 15. Mai 2019 23:52
> To: 2d-dev at openjdk.java.net; 'jdk-updates-dev at openjdk.java.net' <jdk-
> updates-dev at openjdk.java.net>
> Subject: Re: [OpenJDK 2D-Dev] [11u]
> java/awt/FontMetrics/MaxAdvanceIsMax.java test failure (was: [11u] RFR
> 8210782: Upgrade HarfBuzz to the latest 2.3.1)
> 
> 
> 
> On 14/05/2019 17:41, Martin Balao wrote:
> > Hi Goetz,
> >
> > On 5/13/19 1:38 PM, Lindenmaier, Goetz wrote:
> >>
> >> Can I somehow verify that it's the font that has the problem?
> >> Can I fix the font so that the test passes?
> >>
> >
> > I cannot say whether or not the static max advance value in each font is
> > right or not, but let's assume it is. The underlying problem here is
> > that OpenJDK uses a couple of internal FreeType library values to
> > calculate the effects of algorithmic bold and italic in the max advance
> > value -"algorithmic" means that the font is not italic or bold and is up
> > to the rendering engine to generate the desired effect-. These values
> > have changed over the years. What we did in 8218854 [1] was updating the
> > italic value to the latest version and supporting bold in the
> > calculation. Ideally, OpenJDK should not be tight to these values.
> > However, that's not easy to get rid of unless we change the API or the
> > API semantics. All this means that if you use OpenJDK 11 with an old
> > Free Type library, you may have different values and the test may fail.
> >
> > Note: this is just an hypothesis, I couldn't reproduce on my own.
> >
> > I believe the test assertion is right if we consider API semantics only
> > but we can put some constraints given reality.
> >
> > Kind regards,
> > Martin.-
> >
> > --
> > [1] - http://hg.openjdk.java.net/jdk/jdk/rev/0804f29e8be7
> >
> >
> 
> I think the important thing here is to ensure that the test passes with
> the FreeType library included in the OpenJDK sources
> (--with-freetype=system). It's unrealistic to test with every possible
> version of FreeType one could compile against.
> --
> Andrew :)
> 
> Senior Free Java Software Engineer
> Red Hat, Inc. (http://www.redhat.com)
> 
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