Glenn Adams commented on FOP-1969:

I'm not sure why you mean that "this prevents from correctly show some emoji". 
The semantics of the elided controls, e.g., ZWJ, ZWNJ, need to be processed by 
GSUB/GPOS during the process of creating the output glyph sequence. No further 
processing based on ZWJ/ZWNJ should occur after that process. The elision of 
controls operates on the output glyph sequence.

The value of retainControls is presently constant, but it is my plan to 
introduce a new fox:... property that allows an author to determine whether 
control characters are themselves displayed (as control characters). So it's a 
placeholder which value is to be determined by the to be implemented fox:... 
property. Note that whether controls can be displayed by a font is a per-font 

> Surrogate pairs not treated as single unicode codepoint for display purposes
> ----------------------------------------------------------------------------
>                 Key: FOP-1969
>                 URL: https://issues.apache.org/jira/browse/FOP-1969
>             Project: FOP
>          Issue Type: Improvement
>          Components: unqualified
>    Affects Versions: trunk
>         Environment: Operating System: All
> Platform: All
>            Reporter: Glenn Adams
>         Attachments: testing.fo, testing.fo, testing.pdf, testing.pdf, 
> testing.xml, testing.xsl
> unicode codepoints outside of the BMP (base multilingual plane), i.e., whose 
> scalar value is greater than 0xFFFF (65535), are coded as UTF-16 surrogate 
> pairs in Java strings, which pair should be treated as a single codepoint for 
> the purpose of mapping to a glyph in a font (that supports extra-BMP 
> mappings);
> at present, FOP does not correctly handle this case in simple (non complex 
> script) rendering paths;
> furthermore, though some support has been added to handle this in the complex 
> script rendering path, it has not yet been tested, so is not necessarily 
> working there either;

This message was sent by Atlassian JIRA

Reply via email to