[HarfBuzz] please remove U+115F U+1160 from default_ignorable

Konstantin Ritt ritt.ks at gmail.com
Mon Mar 18 18:48:53 PDT 2013

> If "hiding default ignorable" means substituting by zero-width space,
> then the pdf file produced by xetex would not contain U+115F and
> U+1160, resulting in invalid text string when texts are extracted from
> the pdf.

Not exactly. As far as I understand, the correct output for UnBatang
font should be

And if we omit default ignorables that are part of a valid cluster,
then the output for JieubsidaBatang font would be
w/o having to "accumulate" the overall cluster advance in the cluster base.

> Only isolated filler may be ignored. Anyway this is illegal input string.

Indeed. That's why "placeholder" characters like Hangul fillers are
However, we have an option to preserve default ignorables for the case
when the rendering system is able to show something useful for a
broken input text or missing glyphs (i.e. to show the vowel on top of
dotted square to mention the fact that it is missing a leading
consonant before, etc.).


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