Module font 

A bitmap font atlas: a grid of fixed-size glyph cells in one image, and a glyph map (a RON file) from char to cell index. The game names the two files and the glyphs it needs. As a format (ADR-0007), the glyph map is a sidecar read with the PNG beside it (FontAtlasRon). Once the atlas and the game’s text both load, undrawn finds every character of the text the atlas can’t draw.

An atlas may hold a second, wide font beside the narrow one: a wide glyph (a Japanese or Chinese character) takes two cells of the atlas, side by side, and two cells of the screen. CellWidths says which characters are wide, for everything that measures text.

Wide sets. Japanese and Chinese share code points but not shapes (直, 骨, 角), so an atlas may hold several wide fonts, each a set: the unnamed one (FontAtlasDef::wide) and named ones (FontAtlasDef::wide_sets). A language pack names the set it draws from (LangInfo::wide_font), and a wide glyph is looked up in that set first, then in the others (FontAtlasDef::wide_cell), so a pack’s name for itself shows in its own shapes whatever language is on. The punctuation of WIDE_PUNCTUATION is narrow, but wide in a language whose pack says so (CellWidths::in_lang).

Structs

AtlasRect

A pixel rectangle inside the atlas image.

CellWidths

How many cells of the screen each character takes, in one language: two for a character with a wide glyph in any set of the atlas (FontAtlasDef::wide, FontAtlasDef::wide_sets), and for WIDE_PUNCTUATION in a language whose pack has it wide; one for any other. text_width measures text with it, and a glyph buffer prints with it. It also names the language’s wide set, which a renderer looks wide glyphs up in first (wide_font). CellWidths::NARROW has nothing wide. Cheap to clone: the set is shared.

FontAtlasDef

The validated font atlas layout.

FontAtlasRon

A font atlas’s glyph map (font-atlas, .ron), checked as FontAtlasDef::from_source says against the PNG beside it with its name (fonts/atlas.ron and fonts/atlas.png) and the glyphs the game requires.

Constants

FALLBACK_GLYPH

The glyph used when a cell’s glyph is not in the atlas.

WIDE_PUNCTUATION

The punctuation narrow in English and wide in Chinese, with the same code points: “ ” ‘ ’ … —. An atlas may have each both narrow and in a wide set; a language’s pack says which it is (LangInfo::wide_punctuation).

Functions

ascii_spelling

The ASCII spelling of typographic punctuation (’ is ', … is ...), if c is some.

describe

'x' (U+0078), readable even for invisible or confusable glyphs.

is_combining_mark

Whether c is a combining mark (U+0300 to U+036F). A cell draws one beside its letter, not over it, so text needs the accented letter as one character instead (é, U+00E9), and an atlas never keeps one.

is_wide_punctuation

Whether c is one of WIDE_PUNCTUATION.

undrawn

Every character of lang’s text (Lang::texts) that atlas can’t draw in its language: a check across assets, after both load. A language’s wide characters (as its widths have them, Lang::widths: a pack’s or the source’s) must be in the wide set it names, or in any set if it names none; the rest narrow. A pack that names a set the atlas lacks is one error, on its lang.ron (the source, on its folder), and its wide characters aren’t checked. One error per language and character, in the order of their first use, on the file of that use (TextAt::path), naming its key and how many more keys of that language use it. Control characters (a \n) are never errors; a combining mark (is_combining_mark) always is, glyph or not. The errors have no line: a Lang keeps keys, which find the line.

Type Aliases

WideSet

A set of wide glyphs: each character → the cell index of its left half.