[OpenJDK 2D-Dev] [PATCH] 8210058: Algorithmic Italic font leans opposite angle in Printing

[Dmitry Batrak]

 Hello Jay,

Thanks for looking into this!
Since JDK-8218854 JDK already hardcoded the value of FreeType's oblique
modifier (to calculate max advance). After the proposed change, the
hardcoded value will also be used for the actual transform applied to
glyphs, making the code, in a way, more consistent (against the potential
case of FreeType changing the oblique modifier at some point).
As for creating a test for the fix, the test could verify that certain
pixels are filled or not filled to confirm the correct slant direction. I
think it's even possible to do without using Robot - by drawing into a
BufferedImage. But to make the test more reliable, it should use a fixed
font. Is it OK to add some font to JDK codebase along with test code? Or
maybe A.ttf already used in some test cases can be reused? If the latter is
acceptable, should it be copied to the location near the test's source
code, or it can be loaded by a relative reference?

Best regards,
Dmitry Batrak

On Mon, Nov 18, 2019 at 1:29 PM Jayathirth Rao <jayathirth.d.v at oracle.com>
wrote:

> Hi Dmitry,
>
> Thanks for the patch.
> I can sponsor this.
>
> I went through the change and it looks okay.
> But I have a concern about using specific values for matrix based on
> Freetype version for Oblique type. I have less idea about that maybe Phil
> or others can clarify the same.
>
> Regarding adding regression test along with the patch, i think we can use
> AWT Robot to get pixel data to verify the patch.
>
> Thanks,
> Jay
>
> On 18-Nov-2019, at 2:49 PM, Dmitry Batrak <dmitry.batrak at jetbrains.com>
> wrote:
>
> Hello,
>
> Still trying.
> Any volunteers to sponsor/review?
>
> Best regards,
> Dmitry Batrak
>
> On Tue, Nov 5, 2019 at 11:27 AM Dmitry Batrak <dmitry.batrak at jetbrains.com>
> wrote:
>
>> Hello,
>>
>> Let me repeat the request.
>> Any volunteers to sponsor/review?
>>
>> Best regards,
>> Dmitry Batrak
>>
>> ---------- Forwarded message ---------
>> From: Dmitry Batrak <dmitry.batrak at jetbrains.com>
>> Date: Thu, Aug 29, 2019 at 1:58 PM
>> Subject: [PATCH] 8210058: Algorithmic Italic font leans opposite angle in
>> Printing
>> To: 2d-dev <2d-dev at openjdk.java.net>
>>
>>
>> Hello,
>>
>> I'd like to submit a patch for JDK-8210058. I'm not a Committer, so I'll
>> need someone to sponsor this change.
>>
>> The issue is related to the implementation of algorithmic italics in
>> FreeType font scaler. At the moment it uses FT_GlyphSlot_Oblique, but its
>> implementation doesn't take into account the glyph transform, previously
>> set using FT_Set_Transform, and FreeType developers don't seem to have any
>> interest in changing that (see
>> https://savannah.nongnu.org/bugs/index.php?54565).
>> The proposed solution is to include corresponding shear transform
>> explicitly in matrix passed to FT_Set_Transform instead of using
>> FT_GlyphSlot_Oblique.
>> Proposed patch doesn't add any tests, as the change only impacts glyph
>> rendering, and I couldn't think of a reliable way to test that
>> automatically. Existing automated tests from OpenJDK pass after the fix.
>>
>> Issue:  https://bugs.openjdk.java.net/browse/JDK-8210058
>> Webrev: http://cr.openjdk.java.net/~dbatrak/8210058/webrev.00/
>>
>> Best regards,
>> Dmitry Batrak
>>
>
>
>
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