Question

我有一系列ggplot2图形，其水平数不变，但垂直面的数量不同。我想将图形保存为横向a4格式的.pdf。

然而，我不知道如何才能达到相同比例的方面。如果我尝试手动调整它并针对不同数量的垂直面改变width和height，则尺度会在图之间变化，即我得到不同的点尺寸和线宽。

从本质上讲，如何为具有可变数量（垂直）刻面的地块实现相同的刻面尺寸和刻度？

以下是一个例子：

df <- expand.grid(a = 1:2, b = 1:5, x = 1:10)
df$y <- df$x
plot <- ggplot(data = df, mapping = aes(x = x, y = y)) +
            geom_point()
plot1 <- plot + facet_grid(facets = "a ~ b")
plot2 <- plot + facet_grid(facets = ". ~ b")

ggsave(filename = "./figures/plot1.pdf", plot = plot1,
   height = 210, width = 297, units = "mm")

ggsave(filename = "./figures/plot2.pdf", plot = plot2,
   height = 210, width = 297, units = "mm")

Answer 1

我使用此代码将面板大小设置为绝对值，这可能有帮助

set_panel_size <- function(p=NULL, g=ggplotGrob(p), file=NULL, 
                           margin = unit(1,"mm"),
                           width=unit(4, "cm"), 
                           height=unit(4, "cm")){

  panels <- grep("panel", g$layout$name)
  panel_index_w<- unique(g$layout$l[panels])
  panel_index_h<- unique(g$layout$t[panels])
  nw <- length(panel_index_w)
  nh <- length(panel_index_h)

if(getRversion() < "3.3.0"){

   # the following conversion is necessary
   # because there is no `[<-`.unit method
   # so promoting to unit.list allows standard list indexing
   g$widths <- grid:::unit.list(g$widths)
   g$heights <- grid:::unit.list(g$heights)

   g$widths[panel_index_w] <-  rep(list(width),  nw)
   g$heights[panel_index_h] <- rep(list(height), nh)

} else {

   g$widths[panel_index_w] <-  rep(width,  nw)
   g$heights[panel_index_h] <- rep(height, nh)

}

  if(!is.null(file))
    ggsave(file, g, 
           width = convertWidth(sum(g$widths) + margin, 
                                unitTo = "in", valueOnly = TRUE),
           height = convertHeight(sum(g$heights) + margin,  
                                  unitTo = "in", valueOnly = TRUE))

  invisible(g)
}

print.fixed <- function(x) grid.draw(x)

如何在多个多面ggplot2图形中实现相同的面大小和比例？

1 个答案: