systemfonts (version 1.2.1)

glyph_raster: Render glyphs to raster image

Description

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
)

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.

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

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])