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Loading fonts

The Lua plugin installs a global table rmlui, which provides a way to load supported font files from Lua. The simplest way to load a font face is executing the LoadFontFace() function with a single string as a parameter, the file name of the font to load:

rmlui.LoadFontFace('../assets/LatoLatin-Regular.ttf')
rmlui.LoadFontFace('../assets/LatoLatin-Bold.ttf')

However, you may provide two additional parameters (in this order):

  • A fallback option as a boolean type. If enabled, it makes the given font face be used for any unknown characters in other fonts. This is useful for example to provide a single font face for emojis, and another one providing characters for Cyrillic, Greek, and similar. These fonts will then be used whenever characters encountered are not located in the fonts specified by the document. Multiple fallback faces can be used, and they will be prioritized in the order they were loaded.
  • A face_index parameter as an integer type. It allows selection of font faces within font collections. This is useful for loading a single font file with multiple faces.

In this example, different weights of the same font face are loaded, as they are all part of the same file (see OpenType Font Variations), and a fallback for emojis is included:

rmlui.LoadFontFace('data/NotoSansJP-VariableFont_wght.ttf', false, 0)
rmlui.LoadFontFace('data/NotoSansJP-VariableFont_wght.ttf', false, 1)
rmlui.LoadFontFace('data/NotoSansJP-VariableFont_wght.ttf', false, 2)
rmlui.LoadFontFace('seguiemj.ttf', true)