调整 ggplot 中轴刻度标签的位置

Question

下面是我的数据框。

structure(list(start = c(1, 899, 1648, 2024, 4101, 6001, 7124, 
8982), end = c(898, 1647, 2023, 4100, 6000, 7123, 8981, 10000
), gene = c("A", "B", "C", "X", "P", "N", "O", "F"), annotation = c("Replicase", 
"transcription", "Metabolic Pathways", "Metabolic Pathways", 
"transcription", "transcription", "Antibiotic Resistance", "transcription"
), direction = c(1, 1, 1, -1, 1, -1, 1, 1), p = c(449.5, 1273, 
1835.5, 3062, 5050.5, 6562, 8052.5, 9491)), row.names = c(NA, 
-8L), class = "data.frame")

这是我到目前为止编写的代码。

# Mean
filld$p <- rowMeans(subset(filld, select = c(start, end)))

# Plot
ggplot(filld, aes(xmin = start, xmax = end, ymin = 4, ymax = 5, fill = annotation)) + # 
  geom_rect() +
  scale_x_continuous(label = label_bytes("kB"), breaks = scales::pretty_breaks(n = 10)) +
  geom_segment(data = subset(filld, gene %in% gene[duplicated(gene)]),
               aes(x = p, y = 0, xend = p, yend = 4, colour = annotation),
               size = 2) +
  geom_text_repel(aes(x = p, y = 4.5,
                     label = gene, 
                     family = 'Roboto Condensed',
                  ),  nudge_x = .15,
                  box.padding = 0.5,
                  nudge_y = 1,
                  segment.curvature = -0.1,
                  segment.ncp = 3,
                  segment.angle = 20,
                  size=3.5, min.segment.length = 0, max.overlaps = Inf) +
  coord_polar() + 
  scale_y_continuous(limits = c(0, 5.5)) +
  theme_classic() +
  theme(axis.line = element_blank(), 
        #axis.text.x = element_blank(), 
        axis.text.y = element_blank(),
        axis.ticks = element_blank(), 
        axis.title.x = element_blank(), 
        axis.title.y = element_blank(), 
        #axis.ticks.margin = unit(c(0,0,0,0), "lines"), 
        legend.position = "right", 
        panel.background = element_rect(fill = "white"), 
        panel.border = element_blank(), 
        #panel.grid.major = element_blank(), 
        panel.grid.minor = element_blank()
        )

这给了我以下情节：

现在，

1. 我想调整轴刻度标签（1Kb、2Kb、..10Kb）的位置，使它们位于带有刻度的圆圈内。这是为了防止与原始数据集中长度可能较长的基因名称发生任何重叠。

2. 另外，我想知道是否可以将矩形的形状更改为箭头，如下图所示。

预先非常感谢您！

Answer 1

我可能会在数据整形和轴伪造方面投入一些工作。使用geom_textpath，我们可以通过直接标记获得一些相当专业的结果，而不需要大量代码：

library(tidyverse)
library(geomtextpath)

filld %>%
  group_by(gene, annotation) %>%
  summarise(x = c(start, end - c(200, 200, 20, 200, 200), start),
            y = c(17, 17, 16, 18, 20, 19, 19)/4) %>%
  ggplot(aes(x, y)) + 
  geom_polygon(aes(fill = annotation, group = gene), 
               color = "black", linewidth = 0.3) +
  geom_textpath(aes(label = paste("gene", gene), x = p - 100, y = 5.2), 
                data = filld) +
  geom_hline(yintercept = 3.9, color = "gray60") +
  geom_line(aes(group = group), 
            data = data.frame(x = rep(0:9 * 1e3, each = 2),
                              y = rep(c(3.7, 3.9), 10),
                              group = rep(1:10, each = 2))) +
  geom_textpath(aes(label = paste(x, "kB")),
                data = data.frame(x = seq(0, 9000, 1000), y = 3.5)) +
  theme_void(base_size = 16) +
  scale_fill_manual(values = c("#c00000", "#fdc000", "#308298", "#d8d8d8")) +
  ylim(0, 5.5) +
  xlim(0, 10000) +
  coord_polar()