图例

1. 删除图例: theme(legend.position = "none")
2. 删除图例标题: theme(legend.title = element_blank());guides(color = guide_legend(title = NULL))
3. 修改图例标题: labs(legend_title = "")
4. 修改图例名称: scale_fill_manual(labels = c("A" = "A1"))
5. 修改图例大小: guides(color = guide_legend(override.aes = list(size = 4)))
6. 图例位置: theme(legend.position = "bottom")

• 图例在图外的上下左右位置: “top”,”bottom”,”left”,”right”
• 图例在图内左上的位置: theme(legend.position = c(0, 1), legend.justification = c(0, 1))

坐标轴

1. 坐标轴文字倾斜: theme(axis.text.x = element_text(angle = 45, hjust = 1)) theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust = 1))
2. 修改坐标轴文本及范围: scale_y_continuous(expand = c(0,0), limits = c(0, 1), breaks = c(0,0.25,0.5,0.75,1), label = c("0%","25%","50%","75%","100%"))
3. 修改坐标轴标题: labs(x = "", y = "", title = "")

• 标题含有表达式: labs(x = expression(log[2]*'FoldChange', y = expression(-log[10]*'pvalue')))

自定义颜色形状大小

1. 分类型变量: scale_color_manual(values = c("Up"="#b40000","Down"="#004377","Ns"="#bdbdbd"))
2. 连续型变量: scale_color_gradientn(values = seq(0, 1, 0.2), colors = c("#39489f","#39bbec","#f9ed36","#f38466","#b81f25"))
3. 形状: scale_shape_manual(values = c("up-triangle" = 17, "down-triangle" = 25, "circle" = 16))
4. 大小: scale_size_continuous(range = c(0, 1))

主题

1. 透明背景的主题:

• theme_minimal
  有网格线, 无坐标轴, 坐标轴文本为灰色

  theme_minimal(base_size = 12) +
  theme(panel.grid = element_blank(),
      axis.text = element_text(face = "bold", color = "black"),
      axis.title = element_text(face = "bold"),
      legend.title = element_text(face = "bold"),  
      legend.text = element_text(face = "bold"),
      axis.ticks = element_line(size=1.3),
      panel.border = element_rect(linewidth = 1.8, linetype = "solid", color = "black", fill = NA),    
      plot.title = element_text(face = "bold", hjust = 0.5))

• theme_cowplot
  cowplot包的主题,有坐标轴

  theme_cowplot(font_size = 12) + 
  theme(axis.text = element_text(face = "bold"),
      axis.title = element_text(face = "bold"),
      legend.title = element_text(face = "bold"),  
      legend.text = element_text(face = "bold"),
      axis.ticks = element_line(size=1.3),
      axis.line = element_line(size=1.5),
      plot.title = element_text(face = "bold", hjust = 0.5))

保存图片

• ggsave(“.png”, p, width = 8, height = 8, dpi = 300)