yixuan / Fontr
fontr
fontr helps you to extract character glyphs from a specific font, either as bitmaps or outline polygons. This is exactly what showtext does internally, and fontr simply makes it work in the R level.
Quick Examples
The code below generates a matrix representing the bitmap image of the character "C", given the specification of the font.
library(fontr)
ch_C = glyph_bitmap("C", family = "sans", face = "regular", pixel_size = 20)
ch_C
## [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11]
## [1,] 0 0 22 141 217 247 234 194 93 2 0
## [2,] 0 48 234 232 90 15 14 104 243 165 3
## [3,] 9 221 248 43 0 0 0 0 82 255 103
## [4,] 102 255 151 0 0 0 0 0 0 185 119
## [5,] 183 255 69 0 0 0 0 0 0 0 0
## [6,] 230 255 24 0 0 0 0 0 0 0 0
## [7,] 249 255 5 0 0 0 0 0 0 0 0
## [8,] 248 255 7 0 0 0 0 0 0 0 0
## [9,] 226 255 31 0 0 0 0 0 0 0 0
## [10,] 177 255 82 0 0 0 0 0 0 0 0
## [11,] 93 255 172 0 0 0 0 0 0 130 141
## [12,] 5 213 254 65 0 0 0 0 48 246 129
## [13,] 0 39 229 243 105 19 18 90 232 169 5
## [14,] 0 0 18 139 217 247 244 195 88 2 0
## attr(,"class")
## [1] "glyph_bitmap"
plot(ch_C)
The glyph can also be extracted as outline curves that are similar to the SVG path elements.
ch_H = glyph_outline("H", family = "sans", face = "regular")
ch_H
## x y type
## 1 0.54736328 0.0000000 M
## 2 0.54736328 0.3188477 L
## 3 0.17529297 0.3188477 L
## 4 0.17529297 0.0000000 L
## 5 0.08203125 0.0000000 L
## 6 0.08203125 0.6879883 L
## 7 0.17529297 0.6879883 L
## 8 0.17529297 0.3969727 L
## 9 0.54736328 0.3969727 L
## 10 0.54736328 0.6879883 L
## 11 0.64062500 0.6879883 L
## 12 0.64062500 0.0000000 L
## 13 0.54736328 0.0000000 L
The meaning of the characters in the type column can be found in sections
8.3.2 to 8.3.7 of the
SVG specification document.
This form is an exact representation of the glyph outlines that are contained in the font file. However, it is usually more convenient to use polygons to approximate those curves, as the following example shows:
ch_n = glyph_polygon("n", family = "serif", face = "italic", nseg = 10)
head(ch_n, 15)
## x y
## 1 0.3686523 0.3652344
## 2 0.3685352 0.3695459
## 3 0.3681836 0.3736914
## 4 0.3675977 0.3776709
## 5 0.3667773 0.3814844
## 6 0.3657227 0.3851318
## 7 0.3644336 0.3886133
## 8 0.3629102 0.3919287
## 9 0.3611523 0.3950781
## 10 0.3591602 0.3980615
## 11 0.3569336 0.4008789
## 12 0.3544531 0.4034766
## 13 0.3516992 0.4058008
## 14 0.3486719 0.4078516
## 15 0.3453711 0.4096289
plot(ch_n)
The returned data frame contains the x and y coordinates of the vertices of the polygons.
Loading Fonts
The method to load fonts is the same as the showtext package. See the Loading Fonts section of the README file of showtext.
library(sysfonts)
font.add.google("Lobster", "lobster")
plot(glyph_bitmap("Welcome", family = "lobster", rot = 30))
