控制ggplot2中的颜色透明度

Question

我想使用列＆＃39; x＆＃39;来控制手动指定颜色的透明度。值为1到10.我可以通过添加＆＃39; alpha = x＆＃39;来实现。但是在那种情况下，我在散点图中看到了深色点。有人可以帮忙吗？

这是我的代码：

plot1 <- qplot(data=srna[srna$norm_sum > 0 & srna$len > 18 & srna$len < 25, ], x=position,y=norm_sum,colour= len)
plot1 + geom_point(size=4) +
  theme_bw()+
#   scale_alpha_continuous(range = c(0.1, 0.8))+
  scale_colour_manual(values = c("19" = "pink","20" = "blue","21" = "green", "22" = "yellow","23" = "violet", "24" = "red"))+
  theme(panel.grid.minor.x = element_line(colour='grey94'),panel.grid.minor.y = element_line(colour='grey94'),
        panel.grid.major.x = element_line(colour='lightgrey'),panel.grid.major.y = element_line(colour='lightgrey'))

Answer 1

尝试使用the ggplot2 manual中的默认数据重现您的问题（下面的代码），我得到了这个结果。也许你可以指出这里的问题是什么？

# install.packages("ggplot2", dependencies = TRUE)
library(ggplot2)
p <- ggplot(mtcars, aes(wt, mpg))
p + geom_point(size=4, alpha = 0.5, aes(colour = factor(cyl))) + 
       theme_bw() + 
   scale_colour_manual(values = c("4" = "pink","6" = "blue", "8" = "green")) +
    theme(panel.grid.minor.x = element_line(colour='grey94'),
           panel.grid.minor.y = element_line(colour='grey94'),
           panel.grid.major.x = element_line(colour='lightgrey'),
           panel.grid.major.y = element_line(colour='lightgrey'))