R語(yǔ)言繪圖系列：
- R語(yǔ)言可視化及作圖1--基礎(chǔ)繪圖（par函數(shù)，散點(diǎn)圖，盒形圖，條形圖，直方圖）
- R語(yǔ)言可視化及作圖2--低級(jí)繪圖函數(shù)
- R語(yǔ)言可視化及作圖3--圖形顏色選取
- R語(yǔ)言可視化及作圖4--qplot和ggplot2美學(xué)函數(shù)
- R語(yǔ)言可視化及作圖5--ggplot2基本要素和幾何對(duì)象匯總
- R語(yǔ)言可視化及作圖6--ggplot2之點(diǎn)圖、條形圖、盒形圖、直方圖、線圖
- R語(yǔ)言可視化及作圖7--ggplot2之標(biāo)簽、圖例和標(biāo)題繪制
- R語(yǔ)言可視化及作圖8--坐標(biāo)軸自定義和坐標(biāo)系轉(zhuǎn)換
- R語(yǔ)言可視化及作圖9--主題函數(shù)
theme函數(shù)主要的用途是調(diào)節(jié)圖的主題。如下圖，主題主要分為整幅圖plot，坐標(biāo)軸axis，圖例legend，面板panel和分面元素facet。其中經(jīng)常用到的是坐標(biāo)軸主題的修改，比如常見的坐標(biāo)軸字體大小的修改。
theme函數(shù)其實(shí)很簡(jiǎn)單:
theme(主題.部件=element_類型())
主題：plot, axis, legend, panel, facet
部件：title(名字，坐標(biāo)軸名字), line(線，坐標(biāo)軸的xy軸), text(標(biāo)簽，坐標(biāo)軸刻度的數(shù)字), ticks(坐標(biāo)軸刻度的小線條), background(背景)等
類型：rect(所有矩形區(qū)域?qū)傩?，line(所有線屬性)，text(所有文本相關(guān)屬性)，title(所有標(biāo)題屬性)
說明：部件要和類型一致。比如，部件為title，text等文字相關(guān)的元素，那么類型處就為text (具體見上圖)。
1. 整幅圖的主題設(shè)置Plot elements
library(tidyverse)
head(mtcars)
p1=ggplot(mtcars,aes(mpg,disp))+geom_point()
p1+labs(title="xyz")+theme(
plot.background = element_rect(fill = "lightblue", color = "pink", size = 15),
plot.title = element_text(hjust = 1, color = "black", face = "bold",size=15),
plot.margin = margin(t = 30, r = 30, b = 30, l = 30, unit = "pt"))
2. 坐標(biāo)軸主題設(shè)置Axis elements
p1+theme(
axis.line = element_line(color = "lightblue", size = 1),
axis.title = element_text(color = "black", face = "italic"),
axis.ticks = element_line(color = "purple", size = 2),
axis.text = element_text(color = "lightpink"),
axis.text.x = element_text(angle = 45, hjust = 1)
)
3. 面板元素設(shè)置
p1+ theme(
panel.background = element_rect(fill = "white", color = "purple"),
panel.grid = element_line(color = "grey80", size = 0.3)
)
4. 圖例設(shè)置
p2=ggplot(mtcars,aes(mpg,disp,color=cyl))+geom_point()
p2+theme(
legend.background = element_rect(fill = "lightgrey"),
legend.title = element_text(color = "black", size = 15),
legend.key = element_rect(fill = "black"),
legend.text = element_text(color = "blue"),
legend.margin = margin(t = 20, r = 10, b = 10, l = 10, unit = "pt"),
legend.position = "right"
)
5. 參考ggplot2預(yù)設(shè)主題，繪制自己的theme
ggplot2的預(yù)設(shè)主題已經(jīng)寫過了，參考R語(yǔ)言可視化及作圖9--主題函數(shù)。
以theme_linedraw()為例，查看這個(gè)主題設(shè)置了什么參數(shù)
theme_linedraw
## function (base_size = 11, base_family = "", base_line_size = base_size/22,
## base_rect_size = base_size/22)
## {
## half_line <- base_size/2
## theme_bw(base_size = base_size, base_family = base_family,
## base_line_size = base_line_size, base_rect_size = base_rect_size) %+replace%
## theme(axis.text = element_text(colour = "black", size = rel(0.8)),
## axis.ticks = element_line(colour = "black", size = rel(0.5)),
## panel.border = element_rect(fill = NA, colour = "black",
## size = rel(1)), panel.grid = element_line(colour = "black"),
## panel.grid.major = element_line(size = rel(0.1)),
## panel.grid.minor = element_line(size = rel(0.05)),
## strip.background = element_rect(fill = "black"),
## strip.text = element_text(colour = "white", size = rel(0.8),
## margin = margin(0.8 * half_line, 0.8 * half_line,
## 0.8 * half_line, 0.8 * half_line)), complete = TRUE)
## }
## <bytecode: 0x7f818ba6d600>
## <environment: namespace:ggplot2>
它無(wú)非是一個(gè)具有兩個(gè)參數(shù)的函數(shù)：base_size和base_family。其主題部分直接應(yīng)用的theme函數(shù)就是前面寫的主題設(shè)置函數(shù)，這一部分可以直接使用前面介紹的參數(shù)進(jìn)行修改。
