Archive for April, 2018

Contextual Spacing GPOS Features: ‘cspc’ & ‘vcsp’

Japanese line layout is very complex, and the first attempt to standardize its rules and principles was in the JIS X 4051 standard, which was first issued in 1993 with the title 日本語文書の行組版方法 (Line Composition Rules for Japanese Documents in English). There was a revision issued in 1995, and the latest version was issued in 2004 with the slightly different title 日本語文書の組版方法 (Formatting rules for Japanese documents). Another important document is the W3C Working Group Note JLREQ (Requirements for Japanese Text Layout), which provides much of what is described in JIS X 4051, but covers additional areas, and is tailored toward web technologies. Although still considered working drafts, W3C is also preparing similar documents for Chinese and Korean as CLREQ (Requirements for Chinese Text Layout) and KLREQ (Requirements for Hangul Text Layout and Typography), respectively.

This article is not about these standards per se, which are intended for apps and environments that implement sophisticated line layout. Rather, this article is about harsher “plain text” or comparable environments that generally do not need such treatment, yet still benefit from a modest amount of context-based spacing adjustment, particularly to get rid of unwanted space between full-width brackets and other punctuation whose glyphs generally fill half of the em-box. App menus, app dialogs, and simple text editors are examples of where such adjustments can improve text layout in these modest ways.
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This is a brief article to let the readership know that the Unicode Consortium now offers lifetime memberships for individual members. My lifetime membership certificate is shown above.
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