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7. 日本語フォントの要件

Nat McCully edited this page Oct 9, 2023 · 5 revisions

7. 日本語フォントの要件

ここはNatさんが書く。

フォントが持つべきメトリック

特定のフォントフォーマット (TrueType, CFF) に独立の形で。特に、必要なのに現在欠けている項目を逃さないように


Requirements for Japanese Fonts

Introduction

Japanese fonts have key characteristics that are distinct from fonts from other scripts (e.g. Latin script fonts). Many of these key characteristics are shared among Chinese and Korean fonts, as well, but this section will focus on Japanese fonts.

Key differences include: The font design space, the "baselines" used to align runs of different point sizes, the combination of multiple scripts' glyphs in a single font, the way those different glyph sets are aligned and sized to each other, the different orientations of the glyphs in vertical text, the special features used in OpenType fonts for glyph positioning (GPOS) and glyph substitution (GSUB) for Japanese.

This document will go into detail on each of these key differences.

Font Design Space

The Design Space of the font, also referred to as the "Virtual Body" or "Ideographic Em-box", is usually a square or rectangle with the y-dimension equal in height to the point size, and the width either also equal to the point size or some percentage narrower. This space describes the monospaced glyph escapement for the font, and all the so-called "full-width" glyphs are placed within this space.

Glyph Alignment, Line Height and Positioning within the Line

Fonts Contain Both Monospaced and Proportional Glyphs

Adjusting the Metrics of the Latin Glyphs

Vertical Layout

OpenType Features