r - Smaller gap between two legends in one plot (e.g. color and size scale)

Question

how do I reduce the gap between two guides in one plot. In the example below, the two guides are from a color and size scale and I want to change the gap between the two so that the title 'size' is right below the legend-point for 1. Design-wise, it might not make sense in this example but in my actual application it does.

df=data.frame(x=rnorm(100),y=rnorm(100),color=factor(rbinom(100,1,0.5)),size=runif(100))
ggplot(df,aes(x=x,y=y,color=color,size=size)) + geom_point()

Edit: Here is the plot. I would like to make the gap highlighted by the green line and the arrow smaller.

Answer 1

Now it seems to be possible using the theme parameters:

ggplot(df,aes(x=x,y=y,color=color,size=size)) + geom_point() + 
theme(legend.spacing.y = unit(-0.5, "cm"))

You can also try to decrease margins of the legends:

legend.margin = margin(-0.5,0,0,0, unit="cm")

or older

legend.margin=unit(0, "cm")