How to choose values for plot.margin to add more space in the top right of plot using ggplot2-CodePudding

With sample data:

df <- structure(list(date = c("2021-10-1", "2021-10-2", "2021-10-3", 
"2021-10-4", "2021-10-5", "2021-10-6", "2021-10-7", "2021-10-8", 
"2021-10-9", "2021-10-10", "2021-10-11", "2021-10-12", "2021-10-13", 
"2021-10-14"), value = c(190.3, 174.9, 163.2, 168.4, 168.6, 168.2, 
163.5, 161.6, 172.9, 166.5, 175.2, 197.7, 212.1, 177.9), type = c(1L, 
1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L)), class = "data.frame", row.names = c(NA, 
-14L))

and code to plot below:

ggplot(data = df, 
       aes(x=date, y=value, group=type, color = type, fill = type))   
  geom_area(alpha=0.4, position = "identity")  
  theme(
    text = element_text(size=20),
    # plot.margin=unit(c(1, 1, 1.5, 1.2),"cm")
    # top, right, bottom, left
    # plot.margin=unit(c(0, 1.2, 1.5, 10), "pt")
    plot.margin=unit(rep(1, 4),'lines')
        )  
  scale_y_continuous(breaks = range(df$value))  
  scale_x_date(breaks = range(df$date))  
  geom_hline(yintercept=c(min(df$value), max(df$value)), linetype='solid', col=colors[1])  
  geom_text(aes(label = ifelse(date %in% max(date), as.character(date), ""), y = max(value)), color = colors[3], vjust=-0.2, hjust=1, size=6)

Out:

As you can see, the date in red box is not inside of plot, I've tried to adjust margin by adding plot.margin=unit(c(1, 1, 1.5, 1.2), "cm"); plot.margin=unit(c(0, 1.2, 1.5, 10), "pt"), plot.margin=unit(rep(1, 4),'lines'), etc., (even negative values) to theme(), but I didn't success.

I know four values in unit represent top, right, bottom, left, but I don't find a way to correctly adjust them.

Someone could help? Sincere thanks at advance.

CodePudding user response：

One solution would be to use the expand parameter to the scale function. This parameters takes an "expansion vector" which is used to add some space between the data and the axes.

By replicating your code, I was able to visualize the date (within the margin) by adding expand = expansion(mult = c(0, 0.1), add = c(1, 0)) to scale_y_continuous().

Note that I am also using the expansion() function to create the expansion vector which will only expand the top y axis allowing us to visualize the date completely.

So the code would be:

ggplot(data = df, 
       aes(x=date, y=value, group=type, color = type, fill = type))   
  geom_area(alpha=0.4, position = "identity")  
  theme(
    text = element_text(size=20),
    # plot.margin=unit(c(1, 1, 1.5, 1.2),"cm")
    # top, right, bottom, left
    # plot.margin=unit(c(0, 1.2, 1.5, 10), "pt")
    plot.margin=unit(rep(1, 4),'lines')
  )  
  scale_y_continuous(breaks = range(df$value),
                 expand = expansion(mult = c(0, 0.1), add = c(1, 0)))  
  scale_x_date(breaks = range(df$date))  
  geom_hline(yintercept=c(min(df$value), max(df$value)), linetype='solid', col="grey40")  
  geom_text(aes(label = ifelse(date %in% max(date), as.character(date), ""), y = max(value)), color = "grey50", vjust=-0.2, hjust=1, size=6)

Out:

Here are some more information on this parameter and expansion():