Changes/CJKDefaultFontsToNoto

CJK Default Fonts To Noto

Summary

Changes the default fonts for Chinese, Japanese, and Korean (CJK) languages to Google Noto.

Owner

• Name: Akira TAGOH, Peng Wu
• Email: tagoh@redhat.com, pwu@redhat.com
• Release notes owner:

Current status

• Targeted release: Fedora 29
• Last updated: 2018-06-28
• Tracker bug: <will be assigned by the Wrangler>

Detailed Description

This proposal is to change the default fonts for CJK languages to Google Noto and adopts OpenType Collection format to suppress disk space increase as far as possible. Typefaces mapping will change as follows:

Language / f28	Sans-serif	Serif	Monospace
ja	VL Gothic	VL Gothic	VL Gothic
ko	NanumGothic	NanumGothic	NanumGothic
zh-CN	Source Han Sans CN	Source Han Serif CN	Source Han Sans CN
zh-TW	Source Han Sans TW	Source Han Serif TW	Source Han Sans TW

where the italics means the font is a substitute not actually providing the correct face.

Language / f29	Sans-serif	Serif	Monospace
ja	Noto Sans CJK JP	Noto Serif CJK JP	Noto Sans Mono CJK JP
ko	Noto Sans CJK KR	Noto Serif CJK KR	Noto Sans Mono CJK KR
zh-CN	Noto Sans CJK SC	Noto Serif CJK SC	Noto Sans Mono CJK SC
zh-TW	Noto Sans CJK TC	Noto Serif CJK TC	Noto Sans Mono CJK TC

Note that all CJK fonts will be unified into one OpenType Collection format file per weight-variant so only the total size for CJK is given for F29. The disk space is calculated from the font file sizes:

\	ja	ko	zh-CN	zh-TW	Total
f28	3.9M	13.8M	133.1M	77.4M	228.2M
f29	-	-	-	-	288M

Benefit to Fedora

This change will provides better quality of rendering for all of CJK characters. We will now have default installed Serif face for Japanese and Korean, and also a Monospace face for all of CJK languages and keep consistencies in look among those typefaces.

Scope

• Proposal owners:
  • Update CJK fonts packages with the proper priority of fontconfig config files
  • Update fonts group in comps [done]

• Other developers:
  • For application package maintainers:
    • GUI applications that don't support TTC or OTC, will need to be fixed.

• Release engineering: #7592 (a check of an impact with Release Engineering is needed)
  • List of deliverables: All of the installable images should be affected

• Policies and guidelines: N/A

• Trademark approval: N/A

Upgrade/compatibility impact

This change will be done by installing the updated packages. no need to update/modify any configuration files by the hand. the sort of this change may has the objective preference. the users can revert this by uninstalling font packages like this:

# dnf uninstall google-noto-sans-cjk-ttc-fonts google-noto-serif-cjk-ttc-fonts

How To Test

• Check if the default font is changed to Noto:
  • ja
    • LANG=ja_JP.UTF-8 fc-match sans-serif:lang=ja
    • LANG=ja_JP.UTF-8 fc-match serif:lang=ja
    • LANG=ja_JP.UTF-8 fc-match monospace:lang=ja
  • ko
    • LANG=ko_KR.UTF-8 fc-match sans-serif:lang=ko
    • LANG=ko_KR.UTF-8 fc-match serif:lang=ko
    • LANG=ko_KR.UTF-8 fc-match monospace:lang=ko
  • zh-cn
    • LANG=zh_CN.UTF-8 fc-match sans-serif:lang=zh-cn
    • LANG=zh_CN.UTF-8 fc-match serif:lang=zh-cn
    • LANG=zh_CN.UTF-8 fc-match monospace:lang=zh-cn
  • zh-tw
    • LANG=zh_TW.UTF-8 fc-match sans-serif:lang=zh-tw
    • LANG=zh_TW.UTF-8 fc-match serif:lang=zh-tw
    • LANG=zh_TW.UTF-8 fc-match monospace:lang=zh-tw
• Check the following items on applications (GTK+: gedit, gnome-terminal etc, Qt: kate, konsole etc, X/Xft: xterm etc, Others: LibreOffice, firefox etc)
  • Check applications preference if the above fonts are visible
  • Check applications if the above fonts are rendered properly
  • Check applications if those fonts are chosen as the default font for certain language when the generic family names like sans-serif, serif, and monospace is selected.
    • See the above table for mapping between language and families

User Experience

Users will see better quality of rendering for CJK characters on applications and on desktops.

Dependencies

N/A

Contingency Plan

• Contingency mechanism: (What to do? Who will do it?) revert all of changes in packages and comps
• Contingency deadline: Beta freeze
• Blocks release? No

Documentation

• What is the Google Noto CJK fonts?: https://www.google.com/get/noto/help/cjk/
• OpenType specification: https://docs.microsoft.com/en-us/typography/opentype/spec/