Alexander Lange: > > As far as I know, the width of emoji is aligned with ideographic fullwidth > pretty much everywhere. So the question "why not use U+3000?" is almost > certainly going to pop up.
I used to think so, too, but actually trying to mix emojis with East-Asian ideographic characters (space or otherwise) often does not lead to regular alignment, probably due to different fonts with different metrics being used or the font rendering engine switching to a special mode for color glyphs. The reason ultimately does not matter for people writing emoji texts, which may include 2-dimensional alignment across lines. Some early emoji sets had emojis of varying widths and KDDI even had respective “blank” emojis: <http://emoji.digital/kddi-au/>. They were even included in L2/08080r-emoji-proposal as FULL BLANK SPACE, A HALF BLANK SPACE and A QUARTER BLANK SPACE (sic!). ⏹️🔼⏹️ ◀️⏺️▶️ ⏹️🔽⏹️ U+3000 IDEOGRAPHIC SPACE 🔼 ◀️⏺️▶️ ⏹️ ⏹️ U+2001 EM QUAD 🔼 ◀️⏺️▶️ ⏹️ ⏹️ U+2003 EM SPACE 🔼 ◀️⏺️▶️ ⏹️ ⏹️ Hiragana く🔼く ◀️⏺️▶️ ⏹️く⏹️ Katakana ク🔼ク ◀️⏺️▶️ ⏹️ク⏹️ Bopomofo ㄑ🔼ㄑ ◀️⏺️▶️ ⏹️ㄑ⏹️ Hangul ㅅ🔼ㅅ ◀️⏺️▶️ ⏹️ㅅ⏹️ “Ideographic” ㆟🔼㆟ ◀️⏺️▶️ ⏹️㆟⏹️ Whereas mixing those with each other may give regular results: く ク ㄑㅅ㆟
