How to avoid the box in legend key when using aes(fill=kind) in both geom_bar and geom

When using aes(fill=kind) in both geom_bar and geom_smooth, I could not get a clean legend and the same plot as follows :

This is the script:

#!/usr/bin/env Rscript

## load
library(ggplot2)
library(dplyr)

mma <- data.frame(kind=c(rep('A',100), rep('BB', 100), rep('CC',100)),
                  group=c(rep(seq(0.1, 10, by=0.1),3)),
                  frac=runif(n=300, min=0, max=1))

### pic
wd <- 0.05
posa <- position_dodge(width=wd)
ppa <- ggplot(data=mma, aes(x=group, y=frac, group=kind)) 
    geom_bar(aes(fill=kind), stat='identity', position=posa, width=wd) 
    geom_smooth(aes(fill=kind, color=kind), method="loess", span=0.15, size=0.5) 
    labs(x="Time", y="Populations") 
    ## default   mina.png
    ## guides(fill=guide_legend(ncol=3, byrow=TRUE), color="none")     # minb.png
    ## guides(color=guide_legend(ncol=3, byrow=TRUE), fill="none")     # minc.png
    theme(legend.position=c(0.66, 0.92),
          legend.key.size=unit(0.56, 'lines'))

### output
pf <- c(3, 7)
ggsave(file = "./mina.png", height = pf[1], width = pf[2])

output of default setting (mina.png)
disable color (minb.png)
disable fill (minc.png)

I dont know why there is a blue line and a frame in the legend of minb.png (It seems if comes from geom_smooth).

I know the gray rect/box in minc.png could omit by using alpha=1 in geom_smooth. However, it will also erase the span region of loess line.

CodePudding user response：

You could add show.legend = FALSE in your geom_smooth:

library(tidyverse)

mma <- data.frame(kind=c(rep('A',100), rep('BB', 100), rep('CC',100)),
                  group=c(rep(seq(0.1, 10, by=0.1),3)),
                  frac=runif(n=300, min=0, max=1))

### pic
wd <- 0.05
posa <- position_dodge(width=wd)
ggplot(data=mma, aes(x=group, y=frac, group=kind)) 
  geom_bar(aes(fill=kind), stat='identity', position=posa, width=wd) 
  geom_smooth(aes(fill=kind, color=kind), method="loess", span=0.15, size=0.5, show.legend = FALSE) 
  labs(x="Time", y="Populations") 
  ## default   mina.png
  guides(fill=guide_legend(ncol=3, byrow=TRUE), color="none")     # minb.png
  ## guides(color=guide_legend(ncol=3, byrow=TRUE), fill="none")     # minc.png
  theme(legend.position=c(0.66, 0.92),
        legend.key.size=unit(0.56, 'lines'))
#> `geom_smooth()` using formula 'y ~ x'

^{Created on 2022-04-28 by the}