Render glyphs to raster image — glyph

Not all glyphs are encoded as vector outlines (emojis often not). Even for fonts that provide an outline you might be interested in a raster version. This function gives you just that. It converts a glyph into an optimized raster object that can be plotted with e.g. graphics::rasterImage() or grid::grid.raster(). For convenience, you can also use glyph_raster_grob() for plotting the result.

Usage

glyph_raster(
  glyph,
  path,
  index = 0,
  size = 12,
  res = 300,
  col = "black",
  verbose = FALSE
)

Arguments

glyph: The index of the glyph in the font file
path: The path to the font file encoding the glyph
index: The index of the font in the font file
size: The size of the font in big points (1/72 inch)
res: The resolution to render the glyphs to
col: The color of the glyph assuming the glyph doesn't have a native coloring
verbose: Should font and glyph loading errors be reported as warnings

Value

A list of nativeRaster objects (or NULL if it failed to render a given glyph). The nativeRasters have additional attributes attached. "size" will give the size of the glyph in big points and "offset" will give the location of the top-left corner of the raster with respect to where it should be rendered.

Examples

font <- font_info()
glyph <- glyph_info("R", path = font$path, index = font$index)

R <- glyph_raster(glyph$index, font$path, font$index, size = 150)

plot.new()
plot.window(c(0,150), c(0, 150), asp = 1)
rasterImage(R[[1]], 0, 0, attr(R[[1]], "size")[2], attr(R[[1]], "size")[1])