Hi,
I can file a bug on this if I can't find one.
If you can email me the test it will help even if it is not checked in.
-phil.
On 10/26/16, 6:28 AM, Dmitry Batrak wrote:
Hello,
I'd like to propose a patch to make automatic font substitution on
macOS work for surrogate pairs.
I have a Contributor status via agreement signed by JetBrains, hope
someone can sponsor the patch.
Currently, if requested font cannot render a Unicode character
represented by a surrogate pair,
no substitution is performed - Font.canDisplay will return false, and
the character will be
rendered as a 'missing' glyph. This behaviour doesn't violate any
specification, but it looks like
it can be easily improved, as underlying OS framework used under the
hood does support surrogate pairs.
The proposed change consists of two parts. First part is adjusting the
code in CoreTextSupport.m
to handle surrogate pairs while performing char-to-glyph mapping, by
encoding non-displayable
surrogate pairs using negative values of the codepoint, similar to how
non-displayable BMP characters
are encoded. Second part is fixing the rendering code (in
CGGlyphImages.m), where wrong type was used
to pass character values around, so that code for surrogate pairs
handling, already present there,
could work.
I didn't include a test for this change, as it would depend on
OS-specific font fallback mechanism
and fonts installed, but I can create one that will work on a latest
version of macOS with default
fonts, if needed.
Webrev for the fix is available at
http://cr.openjdk.java.net/~avu/rfe_surrogates/webrev.00/
<http://cr.openjdk.java.net/%7Eavu/rfe_surrogates/webrev.00/>
(kindly posted by my colleague, having access to cr.openjdk.java.net
<http://cr.openjdk.java.net>).
To my knowledge, there's no ticket in OpenJDK issue tracker for the
proposed enhancement.
I can submit it via http://bugs.java.com/, if that's an obstacle.
Best regards,
Dmitry Batrak
