Question

我最近在经济学家看到了title had colored words to match the colors of the groups used in the line chart的折线图。我想知道如何使用ggplot2对象执行此操作。下面是一些代码，用于制作包含所有内容的折线图，例如标题中除了彩色字之外的经济学文章。在底部，我显示了所需的输出。

这个问题不是关于显示此信息的理论方法（如直接标注或图例），而是专门针对标题中的单个单词着色。

data <- data.frame(
    group = rep(c('affluence', 'poverty'), each = 6),
    year = rep(c(1970, 1980, 1990, 2000, 2010, 2012), 2),  
    concentration = c(.125, .12, .14, .13, .145, .146, .068, .09, .125, .119, .13, .135)
)

library(ggplot2)

ggplot(data, aes(year, concentration, color = group)) +
    geom_line(size = 1.5) +
    geom_point(size = 4) +
    scale_y_continuous(limits = c(0, .15)) +
    labs(
        x = NULL, y = NULL, 
        title = 'Concentration of affluence and poverty nationwide'
    ) +
    theme_minimal() +
    theme(
        legend.position = 'none'
    ) +
    scale_color_manual(values = c('#EEB422', '#238E68'))

Answer 1

此解决方案基于Displaying text below the plot generated by ggplot2和Colorize parts of the title in a plot（在那里为贡献者提供信用！）。

通过对文本使用phantom占位符，我们避免（大部分）位置的硬编码。

# create text grobs, one for each color
t1 <- textGrob(expression("Concentration of " * phantom(bold("affluence")) * "and" * phantom(bold("poverty")) * " nationwide"),
                 x = 0.5, y = 1.1, gp = gpar(col = "black"))

t2 <- textGrob(expression(phantom("Concentration of ") * bold("affluence") * phantom(" and poverty nationwide")),
                 x = 0.5, y = 1.1, gp = gpar(col = "#EEB422"))

t3 <- textGrob(expression(phantom("Concentration of affluence and ") * bold("poverty") * phantom(" nationwide")),
                 x = 0.5, y = 1.1, gp = gpar(col = "#238E68"))


# plot and add grobs with annotation_custom
p <- ggplot(data, aes(year, concentration, color = group)) +
  geom_line(size = 1.5) +
  geom_point(size = 4) +
  scale_y_continuous(limits = c(0, .15)) +
  labs(x = NULL, y = NULL) +
  theme_minimal() +
  theme(legend.position = 'none',
        # add some extra margin on top
        plot.margin = unit(c(4, 1, 1, 1), "lines")) +
  scale_color_manual(values = c("#EEB422", "#238E68")) +
  annotation_custom(grobTree(t1, t2, t3))

# create gtable and remove clipping
g <- ggplot_gtable(ggplot_build(p))
g$layout$clip[g$layout$name == "panel"] <- "off"

# re-draw
grid.draw(g)

使用大量彩色单词时，应以编程方式更多地创建不同的expression。参见例如multiTitle情节title: words in different colors?的类似问题中的base函数很好，这在ggplot中也很有用。

Answer 2

这是使用ggtext软件包的一种简单且更通用的方式

产生于：

library(ggtext) 

ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
  geom_point(size = 3) +
  scale_color_manual(
    name = NULL,
    values = c(setosa = "#0072B2", virginica = "#009E73", versicolor = "#D55E00"),
    labels = c(
      setosa = "<i style='color:#0072B2'>I. setosa</i>",
      virginica = "<i style='color:#009E73'>I. virginica</i>",
      versicolor = "<i style='color:#D55E00'>I. versicolor</i>")
  ) +
  labs(
    title = "**Fisher's *Iris* dataset**  
    <span style='font-size:11pt'>Sepal width vs. sepal length for 
    <span style='color:#0072B2;'>setosa</span>, 
    <span style='color:#D55E00;'>versicolor</span>, and
    <span style='color:#009E73;'>virginica</span>
    </span>",
    x = "Sepal length (cm)", y = "Sepal width (cm)"
  ) +
  theme_minimal() +
  theme(
    plot.title = element_markdown(lineheight = 1.1),
    legend.text = element_markdown(size = 11)
  )

Answer 3

annotation_custom的一个有点麻烦的解决方案：

ggplot(dat, aes(year, concentration, color = group)) +
  geom_line(size = 1.5) +
  geom_point(size = 4) +
  scale_y_continuous(limits = c(0, 0.16)) +
  labs(x = NULL, y = NULL, title = ' ') +
  theme_minimal() +
  theme(legend.position = 'none') +
  scale_color_manual(values = c('#EEB422', '#238E68')) +
  annotation_custom(textGrob('Concentration of', gp = gpar(col = 'black')), 
                    xmin = 1972, xmax = 1972, ymin = 0.165, ymax = 0.165) +
  annotation_custom(textGrob('affluence', gp = gpar(col = '#EEB422', fontface = 'bold')), 
                    xmin = 1975.7, xmax = 1975.7, ymin = 0.165, ymax = 0.165) +
  annotation_custom(textGrob(' and ', gp = gpar(col = 'black')), 
                    xmin = 1977.65, xmax = 1977.65, ymin = 0.165, ymax = 0.165) +
  annotation_custom(textGrob('poverty', gp = gpar(col = '#238E68', fontface = 'bold')), 
                    xmin = 1979.35, xmax = 1979.35, ymin = 0.165, ymax = 0.165) +
  annotation_custom(textGrob('nationwide', gp = gpar(col = 'black')), 
                    xmin = 1982, xmax = 1982, ymin = 0.165, ymax = 0.165)

给出：

这种方法的主要缺点是需要大量摆弄参数才能将标题的单词放在正确的位置。

ggplot2：标题

3 个答案: