在ggplot中保留不同数目的面板中的面板大小

Question

我想绘制来自不同数据帧的两个图形，然后将它们组合成一个图形（最终图形比较复杂）。每个图都显示了两个类别变量（例如“性别”和“圆形”）上的数据子集。在两个图中，绘制的数据是相同类型的。每个数据集在这些分类变量的级别数上有所不同。

例如，这里的模拟数据绘制在3 x 2的网格中：

require(ggplot2)
set.seed(10)

# Mock data
N <- 10
rounds <- c("A", "B", "C")
NROUNDS <- length(rounds)

df1 <- data.frame(
    Age = 1:N, 
    Response = rnorm(N*2*NROUNDS), 
    Sex = rep(c("M", "F"), each = N), 
    Round = rep(rounds, each = N*2)
)

# Dimension parameters
panel_width <- 2.5
panel_height <- 1.5
ylims <- c(-4, 4)
units <- "in"
panel_spacing <- 0.1
plot_mar <- 0.25

total_x_margin <- panel_spacing + plot_mar*2
total_y_margin <- panel_spacing*(NROUNDS-1) + plot_mar*2

# Plot the figure
six_panel_plot <- ggplot(df1, aes(x = Age, y = Response)) + 
    geom_line(lwd = 2, color = "#CC79A7") + 
    facet_grid(rows = vars(Round), cols = vars(Sex)) + 
    ylim(ylims) + 
    theme(
        panel.spacing.x = unit(panel_spacing, units),
        panel.spacing.y = unit(panel_spacing, units),
        plot.margin = margin(plot_mar, plot_mar, plot_mar, plot_mar, units)
    ) + theme_bw()

# Save the figure
ggsave("six_panel_plot.png", six_panel_plot, 
    width = total_x_margin + panel_width*2, 
    height = total_y_margin + panel_height*NROUNDS)

我已经尝试根据每个维度中的面板数量和边距大小来调整图形大小。但是，如果在4 x 2的网格上创建相似的图形，则各个面板的尺寸与先前的图形不太相同。

# Mock data
N <- 10
rounds <- c("A", "B", "C", "D")
NROUNDS <- length(rounds)

df2 <- data.frame(
    Age = 1:N, 
    Response = rnorm(N*2*NROUNDS), 
    Sex = rep(c("M", "F"), each = N), 
    Round = rep(rounds, each = N*2)
)


# Dimension parameters
panel_width <- 2.5
panel_height <- 1.5
ylims <- c(-4, 4)
units <- "in"
panel_spacing <- 0.1
plot_mar <- 0.25

total_x_margin <- panel_spacing + plot_mar*2
total_y_margin <- panel_spacing*(NROUNDS-1) + plot_mar*2


eight_panel_plot <- ggplot(df2, aes(x = Age, y = Response)) + 
    geom_line(lwd = 2, color = "#CC79A7") + 
    facet_grid(rows = vars(Round), cols = vars(Sex)) + 
    ylim(ylims) + 
    theme(
        panel.spacing.x = unit(panel_spacing, units),
        panel.spacing.y = unit(panel_spacing, units),
        plot.margin = margin(plot_mar, plot_mar, plot_mar, plot_mar, units)
    ) + theme_bw()

ggsave("eight_panel_plot.png", eight_panel_plot, 
    width = total_x_margin + panel_width*2, 
    height = total_y_margin + panel_height*NROUNDS)

如果我在其他软件（Inkscape，Illustrator等）中对齐这些图形，则面板尺寸不相同。

我如何在图形中保留单个panels的大小（而不是简单地使第一个图形具有四行）？我想避免使用其他软件包，仅ggplot2可以吗？

Answer 1

我没有仅适用于ggplot的解决方案，但我将使用ggplot本身依赖的某些软件包（grid和gtable），因此不需要额外的下载。我假设所需的单位以英寸为单位定义，但是很容易更改。

library(grid)

# As per your post
panel_width <- 2.5
panel_height <- 1.5

# Convert plot to gtables
plots <- list(p8 = ggplotGrob(eight_panel_plot), 
              p6 = ggplotGrob(six_panel_plot))

plots <- lapply(plots, function(gt) {
  # Find the positions of panels
  panel_x <- unique(panel_cols(gt)$l)
  panel_y <- unique(panel_rows(gt)$t)
  # Change the sizes of these positions
  gt$widths[panel_x] <- unit(panel_width, "inch")
  gt$heights[panel_y] <- unit(panel_height, "inch")
  gt
})

ggsave("test1.png", plot = plots[[1]])
ggsave("test2.png", plot = plots[[2]])

test1.png：

test2.png：

Answer 2

您可以尝试egg :: set_panel_size（）