使用ggplot不同的交叉線之間的陰影區域

Question

我想用不同的 colors 對以下 plot 的區域進行着色。 我想在綠線的右邊用綠色遮住它，在它的左邊用紅色遮住它。

我已經看過這個類似的問題，但我想在 ggplot 中做： 類似的問題

#Break-even Chart
Q <- seq(0,50,1)
FC <- 50
P <- 7
VC <- 3.6
total_costs <- (FC + VC*Q)
total_revenues <- P*Q
BEP <- round(FC / (P-VC) + 0.5)

df_bep_chart <- as.data.frame(cbind(total_costs, total_revenues, Q))

ggplot(df_bep_chart, aes(Q, total_costs)) + 
  geom_line(group=1, size = 1, col="darkblue") + 
  geom_line(aes(Q, total_revenues), group=1, size = 1, col="darkblue") + 
  theme_bw() + 
  geom_ribbon(aes(ymin = total_revenues, ymax = total_costs), fill = "blue", alpha = .5) +
  geom_vline(aes(xintercept = BEP), col = "green") +
  geom_hline(aes(yintercept = FC), col = "red") +
  labs(title = "Break-Even Chart",
       subtitle = "BEP in Green, Fixed Costs in Red") + 
  xlab("Quanity") + 
  ylab("Money")

Answer 1

嘗試這個。 您必須根據Q是在左側還是在右側來調節填充顏色，並使用scale_fill_manual設置填充 colors：

#Break-even Chart
Q <- seq(0,50,1)
FC <- 50
P <- 7
VC <- 3.6
total_costs <- (FC + VC*Q)
total_revenues <- P*Q
BEP <- round(FC / (P-VC) + 0.5)

df_bep_chart <- as.data.frame(cbind(total_costs, total_revenues, Q))

library(ggplot2)

ggplot(df_bep_chart, aes(Q, total_costs)) + 
  geom_line(group=1, size = 1, col="darkblue") + 
  geom_line(aes(Q, total_revenues), group=1, size = 1, col="darkblue") + 
  theme_bw() + 
  geom_ribbon(aes(ymin = total_revenues, ymax = total_costs, fill = ifelse(Q <= BEP, "red", "green")), alpha = .5) +
  scale_fill_manual(values = c(red = "red", green = "green")) +
  guides(fill = FALSE) +
  geom_vline(aes(xintercept = BEP), col = "green") +
  geom_hline(aes(yintercept = FC), col = "red") +
  labs(title = "Break-Even Chart",
       subtitle = "BEP in Green, Fixed Costs in Red") + 
  xlab("Quanity") + 
  ylab("Money")

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