The standard cluster defined for the Universal Shaping Engine allows multiple pre-base vowels. However, the section “Property-based reordering” does not specify the order of such vowels after reordering – whether they remain in the same order or whether the order is inverted.
Testing with the Balinese vowels ᬾ and ᬿ showed that CoreText and HarfBuzz invert the order of the vowels, while DirectWrite keeps them in the same order.
The Unicode Standard version 13, section 2.11, page 53 states: “By default, the diacritics or other combining characters are positioned from the base character’s glyph outward.” For pre-base vowels, this would imply that the glyph order is inverted from the encoding order.
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The standard cluster defined for the Universal Shaping Engine allows multiple pre-base vowels. However, the section “Property-based reordering” does not specify the order of such vowels after reordering – whether they remain in the same order or whether the order is inverted.
Testing with the Balinese vowels ᬾ and ᬿ showed that CoreText and HarfBuzz invert the order of the vowels, while DirectWrite keeps them in the same order.
The Unicode Standard version 13, section 2.11, page 53 states: “By default, the diacritics or other combining characters are positioned from the base character’s glyph outward.” For pre-base vowels, this would imply that the glyph order is inverted from the encoding order.
Document Details
⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.