调整标题和图边缘之间的空白

我想在标题（轴标题和绘图标题）和绘图边缘之间创建空间。我试过了axis.title and plot.title没有运气。当我尝试不同的值时，情节没有真正改变vjust。我也尝试过plot.margin，但似乎也没有发生任何事情。

Data:

data = data.frame(Category = c(0,1), value = c(40000, 120000))
data$Category = factor(data$Category, levels = c(0,1), labels = c("One-time", "Repeat"))

Plot:

p = ggplot(data, aes(Category, Value)) +
  geom_bar(stat = "identity", width = 0.5, position=position_dodge(width=0.9)) + 
  geom_text(aes(label=Value), position=position_dodge(width=0.9), family = "mono", vjust=-0.5) +
  ggtitle("Title") + 
  scale_y_continuous(expand = c(0,0), limits = c(0,150000)) +
  scale_x_discrete(expand = c(0,0), limits = c("One-time", "Repeat")) +
  xlab("X axis Title") +
  ylab("Y axis Title")

Theme:

p + theme(
  panel.grid.major = element_line(linetype = "blank"), 
  panel.grid.minor = element_line(linetype = "blank"), 
  axis.title = element_text(family = "sans", size = 15), 
  axis.text = element_text(family = "mono", size = 12),
  plot.title = element_text(family = "sans", size = 18),
  panel.background = element_rect(fill = NA)
)

您想使用以下方法来执行此操作margin

    p + theme(
    panel.grid.major = element_line(linetype = "blank"), 
    panel.grid.minor = element_line(linetype = "blank"), 
    axis.title.x = element_text(family = "sans", size = 15, margin=margin(30,0,0,0)), 
    axis.title.y = element_text(family = "sans", size = 15, margin=margin(0,30,0,0)), 
    axis.text = element_text(family = "mono", size = 12),
    plot.title = element_text(family = "sans", size = 18, margin=margin(0,0,30,0)),
    panel.background = element_rect(fill = NA)
  )

请注意，边距需要四个输入，它们按上、右、下、左的顺序指定空间。另请注意，我正在使用开发 ggplot2 版本，因此我的标题默认值是左对齐的。 'hjust' 和 'vjust' 在旧版本的 ggplot2 中工作。