r - 减少整体图例大小(元素和文本)

Question

我正在用 R ggplot2 绘制一些数据。我将两个变量绘制为散点图，另外两个维度绘制为颜色和形状。但是，该图不适用于外部图例(在 x 轴上很小)。

我把传说搬到里面了，但现在传说太大了!有没有办法让它更小而不涉及分别减小每个单独组件的大小(图例标题、图例标签、图例符号)？

library(ggplot2)
p1  = ggplot(allPars, aes(x = log10(growthRate), y = log10(k), col = Background, shape = Timepoint))+
    geom_point(size = 2)+
    theme(legend.position = c(0.5,0.5))+
    xlab("Log10 Growth Rate")+
    ylab("Log10 K")
fig1 = plot_grid(p1, labels = "AUTO")
save_plot(filename = "~/projects/phd/Chapter4/fig4.pdf", plot = fig1, scale = 1)

Answer 1

您必须减小图例元素的大小(覆盖传递的参数 size =2 )并减小字体大小。

创建带有大图例的示例图

library(ggplot2)
p <- ggplot(mtcars, 
            aes(drat, mpg, color = factor(gear), shape = factor(vs))) +
        geom_point(size = 2) +
        theme_classic() +
        theme(legend.position = c(0.1, 0.7))

减小形状元素的大小

# Overwrite given size (2) to 0.5 (super small)
p <- p + guides(shape = guide_legend(override.aes = list(size = 0.5)))

减少颜色元素的大小

p <- p + guides(color = guide_legend(override.aes = list(size = 0.5)))

减小图例字体的大小

p <- p + theme(legend.title = element_text(size = 3), 
               legend.text = element_text(size = 3))

您还可以编写自定义函数来修改您的绘图:

addSmallLegend <- function(myPlot, pointSize = 0.5, textSize = 3, spaceLegend = 0.1) {
    myPlot +
        guides(shape = guide_legend(override.aes = list(size = pointSize)),
               color = guide_legend(override.aes = list(size = pointSize))) +
        theme(legend.title = element_text(size = textSize), 
              legend.text  = element_text(size = textSize),
              legend.key.size = unit(spaceLegend, "lines"))
}

# Apply on original plot
addSmallLegend(p)

最终的情节看起来像这样