Some CJK characters render incorrectly in vertical text, in font-dependent ways
GIMP version: 2.10.6
Operating System: Windows
Package: Installer
Description of the bug
Note: the character
This is probably Pango's fault.
When setting text in a vertical writing direction with the text tool, certain characters will be displayed in their horizontal form, if the font doesn't have vertical versions of their glyphs. This is most obvious with certain punctuation marks like
According to unicode, when a font doesn't have vertical glyphs for certain characters, they have to be displayed as rotated versions of their horizontal glyphs, in line with the following specifications:
- https://www.unicode.org/reports/tr50/
- https://www.unicode.org/Public/vertical/revision-17/VerticalOrientation-17.txt
Reproduction
Reproduction steps:
Try to set text with affected characters (like ー
Expected behavior:
The long vowel mark and wavy dash should have a vertical orientation and the ideographic full stop should be in the top right corner of its cell, regardless of the font being used.
Using IPAexGothic, another libre font, renders correctly:
Actual result:
Using Noto Serif CJK JP, a libre font:
Using HanaMinA, part of Hanazono Mincho, another libre font:
Additional information
Related Pango issue: pango#322 (closed)