ggplot2繪圖系統——主題函數
1. theme函數
theme_*系列函數提供了9種不同的風格。
theme_grey/gray/bw/linedraw/light/minimal/classic/dark/void都只有2個參數：base_size表示文字大小，base_family表示字體。
mg <- ggplot(mtcars,aes(x=mpg,y=wt))+geom_point()
a=mg+theme_bw()+geom_text(aes(x=25,y=5),label='theme_bw',color='red',size=10)
b=mg+theme_classic()+geom_text(aes(x=25,y=5),label='theme_classic',color='red',size=10)
c=mg+theme_dark()+geom_text(aes(x=25,y=5),label='theme_dark',color='red',size=10)
d=mg+theme_light()+geom_text(aes(x=25,y=5),label='theme_light',color='red',size=10)
e=mg+theme_get()+geom_text(aes(x=25,y=5),label='theme_get',color='red',size=10)
f=mg+theme_linedraw()+geom_text(aes(x=25,y=5),label='theme_linedraw',color='red',size=10)
g=mg+theme_replace()+geom_text(aes(x=25,y=5),label='theme_replace',color='red',size=10)
h=mg+theme_minimal()+geom_text(aes(x=25,y=5),label='theme_minimal',color='red',size=10)
i=mg+theme_void()+geom_text(aes(x=25,y=5),label='theme_void',color='red',size=10)
grid.arrange(a,b,c,d,e,f,g,h,i,ncol=3)
2. ggthemes包
ggplot2擴展包，包括主題函數和標度函數。
ggthemes包種最常見的12種主題。
p <- ggplot(mtcars,aes(x=wt,y=mpg,color=factor(gear)))+
geom_point()+labs(title = 'Cars')+
theme(plot.title = element_text(hjust = 0.5,family = 'Times New Roman'))
a <- p+theme_economist()+scale_color_economist()+
geom_text(aes(x=4,y=30),label='theme_economist',color='deeppink')
b <- p+theme_solarized()+scale_color_solarized('blue')+
geom_text(aes(x=4,y=30),label='theme_solarized',color='deeppink')
c <- p+theme_solarized(light = FALSE)+scale_color_solarized('red')+
geom_text(aes(x=4,y=30),label='theme_dark',color='deeppink')
d <- p+theme_solarized(light = FALSE)+scale_color_solarized('blue')+
geom_text(aes(x=4,y=30),label='theme_dark2',color='deeppink')
grid.arrange(a,b,c,d,ncol=2)
e <- p+theme_stata()+scale_color_stata()+geom_text(aes(x=4,y=30),label='theme_stata',color='deeppink')
f <- p+theme_igray()+geom_text(aes(x=4,y=30),label='theme_igray',color='deeppink')
g <- p+theme_igray()+scale_color_tableau()+geom_text(aes(x=4,y=30),label='theme_igray',color='deeppink')
h <- p+theme_wsj()+scale_color_wsj('colors6','')+geom_text(aes(x=4,y=30),label='theme_wsj',color='deeppink')
grid.arrange(e,f,g,h,ncol=2)
i <- p+theme_calc()+scale_color_calc()+geom_text(aes(x=4,y=30),label='theme_calc',color='deeppink')
j <- p+theme_pander()+scale_color_pander()+geom_text(aes(x=4,y=30),label='theme_pander',color='deeppink')
k <- p+theme_hc()+scale_color_hc()+geom_text(aes(x=4,y=30),label='theme_hc',color='deeppink')
l <- p+theme_hc(bgcolor = 'darkunica')+scale_color_hc('darkunica')+geom_text(aes(x=4,y=30),label='theme_hc2',color='deeppink')
grid.arrange(i,j,k,l,ncol=2)
除了ggthemes包，還有artyfarty和ggthemr包也可設置主題，或者自定義主題函數。