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Compute strings sizes

Source: R/text-metrics.R
strings_sizes.Rd

Determines widths, ascent and descent in inches. Font lookup is performed by 'systemfonts' (so any font registered via systemfonts::register_font(), register_gfont(), or font_set() is found), then the metrics stored in the font file are read with FreeType, without scaling or hinting:

  • the width is the sum of the glyph advances (no kerning);

  • the ascent and the descent are those of the box enclosing the ink of the glyphs, so they depend on the text ("xxx" has no descent).

The results only depend on the font file: the same file gives the same values on every platform. They are accurate for devices whose rendering finds the same font – this is guaranteed for 'systemfonts'-based devices (ragg, svglite, ggiraph) and true for cairo_pdf() when the font is also installed at the system level. For devices with their own font engine (pdf(), png(), ...) the metrics may not match the rendering.

When the font file found cannot be read, a warning is issued and the default sans-serif font is used. NA strings give NA metrics; invalid UTF-8 strings are measured as empty strings.

Usage

strings_sizes(
  x,
  fontname = "sans",
  fontsize = 10,
  bold = FALSE,
  italic = FALSE
)

Arguments

x

A character vector of strings to measure. All arguments are vectorized and recycled to match the length of x.

fontname

A character vector specifying the font family name (e.g., "sans", "serif", "mono"). Default is "sans". This argument is vectorized.

fontsize

A numeric vector specifying the font size in points. Default is 10. This argument is vectorized.

bold

A logical vector indicating whether the text should be bold. Default is FALSE. This argument is vectorized.

italic

A logical vector indicating whether the text should be italic. Default is FALSE. This argument is vectorized.

See also

Other functions for font metrics: m_str_extents(), str_metrics()

Examples

strings_sizes(letters)
#>         width     ascent     descent
#> 1  0.08511013 0.07778592 0.001966688
#> 2  0.08816189 0.10552300 0.001966688
#> 3  0.07636176 0.07778592 0.001966688
#> 4  0.08816189 0.10552300 0.001966688
#> 5  0.08544922 0.07778592 0.001966688
#> 6  0.04889594 0.10552300 0.000000000
#> 7  0.08816189 0.07778592 0.028889974
#> 8  0.08802626 0.10552300 0.000000000
#> 9  0.03858778 0.10552300 0.000000000
#> 10 0.03858778 0.10552300 0.028889974
#> 11 0.08043077 0.10552300 0.000000000
#> 12 0.03858778 0.10552300 0.000000000
#> 13 0.13529460 0.07778592 0.000000000
#> 14 0.08802626 0.07778592 0.000000000
#> 15 0.08497450 0.07778592 0.001966688
#> 16 0.08816189 0.07778592 0.028889974
#> 17 0.08816189 0.07778592 0.028889974
#> 18 0.05710178 0.07778592 0.000000000
#> 19 0.07236057 0.07778592 0.001966688
#> 20 0.05445692 0.09752062 0.000000000
#> 21 0.08802626 0.07778592 0.001966688
#> 22 0.08219401 0.07595486 0.000000000
#> 23 0.11359321 0.07595486 0.000000000
#> 24 0.08219401 0.07595486 0.000000000
#> 25 0.08219401 0.07595486 0.028889974
#> 26 0.07290310 0.07595486 0.000000000
strings_sizes("Hello World!", bold = TRUE, italic = FALSE,
  fontname = "sans", fontsize = 12)
#>      width    ascent     descent
#> 1 1.172282 0.1266276 0.002360026