On 5/12/2021 11:46 PM, Marcel Fabian Krüger wrote:
> Hi,
> 
> recently we got an interesting bug report in luaotfload (the original report
> is at https://github.com/latex3/luaotfload/issues/184) which relates to the
> ConTeXt fontloader. Take the following ConTeXt example:
> 
>      \starttext
>      \definefontfeature [default:bold] [default] [axis={weight=500}]
>      \definedfont[file:NotoSansCJKsc-VF.otf*default:bold @ 10pt]
>      
>      U+5E2E 帮
>      
>      \stoptext
> 
> The font is available at
> https://github.com/googlefonts/noto-cjk/raw/main/Sans/Variable/OTF/NotoSansCJKsc-VF.otf.
> 
> This compiles correctly, but the CJK glyph do not appear since
> it's Type2 CharString is invalid. The CFF2 CharStrings of this
> glyph invokes the rrcurveto operator with 63 arguments, which is

66 etc .. multiples of 6

> allowed in CFF2 where the argument limit is 513, but not allowed in
> Type2 where the limit is at 48.

a rather low limit right from the start (we can assume only rrcurveto is 
affected)

> It would be great if ConTeXt could check for this and insert additional
> rrcuveto operators when necessary to avoid this issue.
after some experiments ... attached

(no upload yet as i'm renaming some low level helpers which needs testing)

Hans

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