在如何修改畫圖使用的字體這篇文章中诸尽，我介紹了一種解決R圖里字體的方案——extrafont包蠢箩。今天意外看到另一個解決字體問題的包乌昔，再次推薦和介紹一番隙疚。
showtext幫助用戶在圖中更好地使用多種類型字體，包括TrueType磕道、OpenType等供屉。該包主要嘗試做以下兩件事情：
- 讓R知道這些字體
- 讓這些字體繪制文本
該包的動力在于在R圖中使用非標準字體不方便，比如中文字體溺蕉。
簡單實例
library(showtext)
## Loading Google fonts (http://www.google.com/fonts)
font_add_google("Gochi Hand", "gochi")
font_add_google("Schoolbell", "bell")
font_add_google("Covered By Your Grace", "grace")
font_add_google("Rock Salt", "rock")
## Automatically use showtext to render text for future devices
showtext_auto()
## Tell showtext the resolution of the device,
## only needed for bitmap graphics. Default is 96
## showtext_opts(dpi = 96)
set.seed(123)
x = rnorm(10)
y = 1 + x + rnorm(10, sd = 0.2)
y[1] = 5
mod = lm(y ~ x)
## Plotting functions as usual
## Open a graphics device if you want, e.g.
## png("demo.png", 700, 600, res = 96)
op = par(cex.lab = 2, cex.axis = 1.5, cex.main = 2)
plot(x, y, pch = 16, col = "steelblue",
xlab = "X variable", ylab = "Y variable", family = "gochi")
grid()
title("Draw Plots Before You Fit A Regression", family = "bell")
text(-0.5, 4.5, "This is the outlier", cex = 2, col = "steelblue",
family = "grace")
abline(coef(mod))
abline(1, 1, col = "red")
par(family = "rock")
text(1, 1, expression(paste("True model: ", y == x + 1)),
cex = 1.5, col = "red", srt = 20)
text(0, 2, expression(paste("OLS: ", hat(y) == 0.79 * x + 1.49)),
cex = 1.5, srt = 15)
legend("topright", legend = c("Truth", "OLS"), col = c("red", "black"), lty = 1)
par(op)
在這個例子中我們首先導入了一些在線谷歌字體伶丐，然后用showtext_auto()函數告訴R控制圖的文本字體輸出，接下來的所有部分就和平常我們畫圖一樣疯特。
This example should work on most graphics devices, including pdf(), png(), postscript(), and on-screen devices such as windows() on Windows and x11() on Linux.
用法
分為以下幾步：
- 載入字體
- 打開繪圖設備
- 聲明你想要使用showtext畫文本圖
- 畫圖
- 關閉畫圖設備
If you want to use showtext globally, you can call the function showtext_auto() once, and then all the devices after that will automatically use showtext to render text, as the example in the beginning shows.
If you want to have finer control on which part of the code should use showtext, functions showtext_begin() and showtext_end() will help.
載入字體
載入字體是通過sysfonts包實現(xiàn)的哗魂。
The easy way to load font into showtext is by calling font.add(family, regular), where family is the name that you assign to that font (so that later you can call par(family = …) to use this font in plotting), and regular is the path to the font file. That is to say, only knowing the “font name” is not enough, since they are usually system dependent. On the contrary, font file is the entity that actually provides the character glyphs.
因為一般系統(tǒng)字體放在標準目錄下，所以我們can use font.paths() to check the current search path or add a new one, and use font.files() to list available font files in the search path.
font.paths()
#> 'fond.paths()' is now renamed to 'font_paths()'
#> The old version still works, but consider using the new function in future code
#> [1] "/Library/Fonts" "/Users/wsx/Library/Fonts"
font.files()
#> 'font.files()' is now renamed to 'font_files()'
#> The old version still works, but consider using the new function in future code
#> [1] "Al Nile.ttc" "Al Tarikh.ttc"
#> [3] "AlBayan.ttc" "AmericanTypewriter.ttc"
#> [5] "Andale Mono.ttf" "Apple Chancery.ttf"
#> [7] "AppleGothic.ttf" "AppleMyungjo.ttf"
#> [9] "Arial Black.ttf" "Arial Bold Italic.ttf"
#> [11] "Arial Bold.ttf" "Arial Italic.ttf"
#> [13] "Arial Narrow Bold Italic.ttf" "Arial Narrow Bold.ttf"
#> [15] "Arial Narrow Italic.ttf" "Arial Narrow.ttf"
#> [17] "Arial Rounded Bold.ttf" "Arial Unicode.ttf"
#> [19] "Arial.ttf" "Athelas.ttc"
#> [21] "Ayuthaya.ttf" "Baghdad.ttc"
#> [23] "Bangla MN.ttc" "Bangla Sangam MN.ttc"
#> [25] "Baskerville.ttc" "Beirut.ttc"
#> [27] "BigCaslon.ttf" "Bodoni 72 OS.ttc"
#> [29] "Bodoni 72 Smallcaps Book.ttf" "Bodoni 72.ttc"
#> [31] "Bodoni Ornaments.ttf" "Bradley Hand Bold.ttf"
#> [33] "Brush Script.ttf" "Chalkboard.ttc"
#> [35] "ChalkboardSE.ttc" "Chalkduster.ttf"
#> [37] "Charter.ttc" "Cochin.ttc"
#> [39] "Comic Sans MS Bold.ttf" "Comic Sans MS.ttf"
#> [41] "Copperplate.ttc" "Corsiva.ttc"
#> [43] "Courier New Bold Italic.ttf" "Courier New Bold.ttf"
#> [45] "Courier New Italic.ttf" "Courier New.ttf"
#> [47] "Damascus.ttc" "DecoTypeNaskh.ttc"
#> [49] "Devanagari Sangam MN.ttc" "DevanagariMT.ttc"
#> [51] "Didot.ttc" "DIN Alternate Bold.ttf"
#> [53] "DIN Condensed Bold.ttf" "Diwan Kufi.ttc"
#> [55] "Diwan Thuluth.ttf" "EuphemiaCAS.ttc"
#> [57] "Farah.ttc" "Farisi.ttf"
#> [59] "Futura.ttc" "Georgia Bold Italic.ttf"
#> [61] "Georgia Bold.ttf" "Georgia Italic.ttf"
#> [63] "Georgia.ttf" "GillSans.ttc"
#> [65] "Gujarati Sangam MN.ttc" "GujaratiMT.ttc"
#> [67] "Gurmukhi MN.ttc" "Gurmukhi Sangam MN.ttc"
#> [69] "Gurmukhi.ttf" "Herculanum.ttf"
#> [71] "Hoefler Text Ornaments.ttf" "Hoefler Text.ttc"
#> [73] "Impact.ttf" "InaiMathi-MN.ttc"
#> [75] "Iowan Old Style.ttc" "ITFDevanagari.ttc"
#> [77] "Kailasa.ttc" "Kannada MN.ttc"
#> [79] "Kannada Sangam MN.ttc" "Kefa.ttc"
#> [81] "Khmer MN.ttc" "Khmer Sangam MN.ttf"
#> [83] "Kokonor.ttf" "Krungthep.ttf"
#> [85] "KufiStandardGK.ttc" "Lao MN.ttc"
#> [87] "Lao Sangam MN.ttf" "Luminari.ttf"
#> [89] "Malayalam MN.ttc" "Malayalam Sangam MN.ttc"
#> [91] "Marion.ttc" "Microsoft Sans Serif.ttf"
#> [93] "Mishafi Gold.ttf" "Mishafi.ttf"
#> [95] "Mshtakan.ttc" "Muna.ttc"
#> [97] "Myanmar MN.ttc" "Myanmar Sangam MN.ttc"
#> [99] "Nadeem.ttc" "NewPeninimMT.ttc"
#> [101] "NISC18030.ttf" "Oriya MN.ttc"
#> [103] "Oriya Sangam MN.ttc" "Papyrus.ttc"
#> [105] "Phosphate.ttc" "PlantagenetCherokee.ttf"
#> [107] "PTMono.ttc" "PTSans.ttc"
#> [109] "PTSerif.ttc" "PTSerifCaption.ttc"
#> [111] "Raanana.ttc" "Rockwell.ttc"
#> [113] "Sana.ttc" "Sathu.ttf"
#> [115] "Savoye LET.ttc" "Seravek.ttc"
#> [117] "Shree714.ttc" "SignPainter.ttc"
#> [119] "Silom.ttf" "Sinhala MN.ttc"
#> [121] "Sinhala Sangam MN.ttc" "Skia.ttf"
#> [123] "SnellRoundhand.ttc" "Songti.ttc"
#> [125] "STIXGeneral.otf" "STIXGeneralBol.otf"
#> [127] "STIXGeneralBolIta.otf" "STIXGeneralItalic.otf"
#> [129] "STIXIntDBol.otf" "STIXIntDReg.otf"
#> [131] "STIXIntSmBol.otf" "STIXIntSmReg.otf"
#> [133] "STIXIntUpBol.otf" "STIXIntUpDBol.otf"
#> [135] "STIXIntUpDReg.otf" "STIXIntUpReg.otf"
#> [137] "STIXIntUpSmBol.otf" "STIXIntUpSmReg.otf"
#> [139] "STIXNonUni.otf" "STIXNonUniBol.otf"
#> [141] "STIXNonUniBolIta.otf" "STIXNonUniIta.otf"
#> [143] "STIXSizFiveSymReg.otf" "STIXSizFourSymBol.otf"
#> [145] "STIXSizFourSymReg.otf" "STIXSizOneSymBol.otf"
#> [147] "STIXSizOneSymReg.otf" "STIXSizThreeSymBol.otf"
#> [149] "STIXSizThreeSymReg.otf" "STIXSizTwoSymBol.otf"
#> [151] "STIXSizTwoSymReg.otf" "STIXVar.otf"
#> [153] "STIXVarBol.otf" "SukhumvitSet.ttc"
#> [155] "SuperClarendon.ttc" "Tahoma Bold.ttf"
#> [157] "Tahoma.ttf" "Tamil MN.ttc"
#> [159] "Tamil Sangam MN.ttc" "Telugu MN.ttc"
#> [161] "Telugu Sangam MN.ttc" "Times New Roman Bold Italic.ttf"
#> [163] "Times New Roman Bold.ttf" "Times New Roman Italic.ttf"
#> [165] "Times New Roman.ttf" "Trattatello.ttf"
#> [167] "Trebuchet MS Bold Italic.ttf" "Trebuchet MS Bold.ttf"
#> [169] "Trebuchet MS Italic.ttf" "Trebuchet MS.ttf"
#> [171] "Verdana Bold Italic.ttf" "Verdana Bold.ttf"
#> [173] "Verdana Italic.ttf" "Verdana.ttf"
#> [175] "Waseem.ttc" "Webdings.ttf"
#> [177] "Wingdings 2.ttf" "Wingdings 3.ttf"
#> [179] "Wingdings.ttf" "Zapfino.ttf"
At present font.add() supports TrueType fonts(.ttf/.ttc) and OpenType fonts(*.otf), and adding new font type is trivial as long as FreeType supports it.
Note that showtext includes an open source CJK font WenQuanYi Micro Hei. If you just want to show CJK text in your graph, you do not need to add any extra font at all.
注意漓雅，there are many free fonts available and accessible on the web, for instance the Google Fonts project (https://www.google.com/fonts). sysfonts provides an interface to automatically download and register those fonts through the function font_add_google(), as the example below shows.
library(showtext)
font_add_google("Lobster", "lobster")
showtext_auto()
plot(1, pch = 16, cex = 3)
text(1, 1.1, "A fancy dot", family = "lobster", col = "steelblue", cex = 3)
更多例子和用法查看說明文檔https://github.com/yixuan/showtext
從使用上看录别，我更喜歡這個包~
