Font - Rive

A font that shapes and draws text. Fonts come from the file’s assets with context:font(name), from a view model Property<Font>, or from bytes with Font.decode. Metrics are for a 1 point font and grow negative upwards, so multiply by the size and expect ascent below zero.

type Label = {
  text: Text,
}

function init(self: Label, context: Context): boolean
  local font = context:font('Inter')
  if font then
    self.text:append('Hello', { font = font, size = 24, paint = Paint.new() })
  end
  return true
end

Fields

`ascent`

Distance from the baseline to the top of the em box for a 1 point font, negative.

`descent`

Distance from the baseline to the bottom of the em box for a 1 point font.

`capHeight`

Distance from the baseline to the top of capital letters, negative.

`xHeight`

Distance from the baseline to the top of lowercase letters, negative.

`weight`

Weight from 1 to 1000, 400 being regular.

`isItalic`

`axes`

Variable axes the font offers.

`features`

Four letter OpenType feature tags the font offers, such as ‘liga’.

Static Functions

`decode`

decode(bytes: buffer) -> Font?

Decodes a TrueType or OpenType font from bytes a script obtained itself, such as a downloaded file. Font files in a project are font assets, reached with context:font, not blobs. Returns nil when the bytes are not a font.

local font = Font.decode(downloadedBytes)

Methods

`lineHeight`

lineHeight(size: number) -> number

Height of one line of text at the given size.

`hasGlyph`

hasGlyph(codepoint: number) -> boolean

Whether the font has a glyph for the unicode codepoint.

`axisValue`

axisValue(tag: string) -> number

Current value of a variable axis, by tag.

`withOptions`

withOptions(axes: {[string]: number}?, features: {[string]: number}?) -> Font

A new font at the given axis values and feature settings.

local bold = font:withOptions({ wght = 700 }, { liga = 0 })

`glyphPath`

glyphPath(glyphId: number) -> Path

Outline of one glyph in 1 point units with the baseline at y 0, wound for a clockwise fill. Scale by the font size to draw it.

​Fields

​ascent

​descent

​capHeight

​xHeight

​weight

​isItalic

​axes

​features

​Static Functions

​decode

​Methods

​lineHeight

​hasGlyph

​axisValue

​withOptions

​glyphPath