多個圖例設置圖例項圈顏色

Question

我有這樣的情節：

dates = c("2017-03-13","2017-03-13","2017-03-14","2017-03-14","2017-03-14") 
value = c(5,6,7,8,9) 
group = c("A","B","A","B","C") 
size = c(10,20,30,40,50) 
data =data.frame(dates= dates, value = value, group = group, size = size) 
ggplot(data, aes(x = dates, y = value, group = group)) + geom_point(aes (color = as.factor(group), size= size))+ 
scale_color_manual(name="group", 
        labels = c(A="A",B= "B",C = "C"), 
        values = c(A="green",B="red" , C = "orange") 
) + theme(
    panel.background = element_rect(fill = "black", colour = "black"), 
    legend.key = element_rect(colour = "black", fill = "black") 
) 

有2個問題：

（1）目前在大小傳說中的圓是黑色，背景是黑色的。如何使圓圈的顏色變爲紅色，以便您可以在黑色背景上看到圓圈？

Answer 1

您需要override.aes在guide_legend更改圖例中的美學設置而不更改圖。

+ guides(size = guide_legend(override.aes = list(color = "red")))