class Eagle::TrueType

• Eagle::TrueType
• Reference
• Object

Overview

A TrueType font file, parsed in pure Crystal: glyph lookup, metrics, kerning and outlines.

Most games use Font.load, which wraps this in a TrueTypeFont. Use TrueType directly for tools, such as inspecting a font or rasterizing glyphs into your own atlas.

ttf = TrueType.load("res://fonts/Inter.ttf")
g_index = ttf.glyph_index('A')
bitmap = ttf.rasterize(g_index, 32.0_f32 / ttf.units_per_em)
image = bitmap.to_image

Supports glyf outlines, cmap formats 4, 6 and 12, composite glyphs and kern table format 0. OpenType CFF fonts (.otf) aren't supported.

Defined in:

eagle/graphics/truetype.cr

Constructors

• .load(path : String) : TrueType

  Reads and parses a font file.

• .new(data : Bytes)

  Parses a font from raw bytes.

Instance Method Summary

• #advance(glyph : Int32) : Int32

  Horizontal advance of a glyph, in font units.

• #ascent : Int32

  Height above the baseline, in font units.

• #descent : Int32

  Depth below the baseline, in font units (negative).

• #family_name : String

  The family name from the font's name table, such as "Inter".

• #glyph_count : Int32

  Number of glyphs in the font.

• #glyph_index(char : Char) : Int32

  --- public metrics --- The glyph index for char, or 0 (the missing-glyph box) if the font lacks it.

• #has_glyph?(char : Char) : Bool

  True when the font has a glyph for char.

• #kern_pairs : Int32

  Number of kerning pairs in the font.

• #kerning(left : Int32, right : Int32) : Int32

  Kerning between two glyph indices, in font units.

• #left_side_bearing(glyph : Int32) : Int32

  Left side bearing of a glyph, in font units.

• #line_gap : Int32

  Extra gap between lines, in font units.

• #outline(glyph : Int32) : GlyphOutline

  --- outlines --- The contours of a glyph.

• #rasterize(glyph : Int32, scale : Float32, pad : Int32 = 1) : Bitmap

  Rasterizes a glyph with anti-aliasing.

• #units_per_em : Int32

  Font units per em.

Constructor Detail

Instance Method Detail