Unable to justify legend when combining plots with plot_grid() about cowplot

[Ax3man]

I think this issue is fixed with the new ggplot2. Using theme(legend.justification = c(0,0.5) will now correctly justify the legends.

[clauswilke]

This seems to be fixed, so I'm closing this issue. Please reopen if I'm mistaken.

[clauswilke]

It would help if you could provide the code that generates this figure, or a different one with the same issue. Fundamentally, this is due to how ggplot2 creates the legend grob, so outside of my control. But there's probably a work-around that can be found.

[aviast]

Sure, here it is.

library(cowplot)
library(plyr)

x <- seq(from = -pi, to = pi, by = 0.01)
y1 <- cos(x)
y2 <- sin(x)
y3 <- tan(x)

df <- data.frame(x = rep(x, 3),
                 y = c(y1, y2, y3),
                 label = rep(c("short","mmeeddiiuumm","looooooooooooooooooooooong"), each = length(x)),
                 stringsAsFactors = FALSE)

plots <- dlply(df, .(label), function(trig) {
  ggplot(trig, aes(x = x, y = y, colour = label)) +
    geom_line() +
    theme(legend.justification = c(0,0),
          legend.title = element_blank())
})

plot_grid(plotlist = plots, align = "v", ncol = 1)

ggsave(filename = "cowplot.png", width = 10, height = 10, units = "cm", scale = 2)

[clauswilke]

Workaround: Do the alignment manually. Importantly, this sets the panel width to a fixed value, when normally in ggplot the panel expands as needed. So you need to choose the appropriate panel width given the size at which you save the figure.

These kinds of problems come up all the time, and we'll probably need convenience functions that make this kind of alignment manipulation easier. Not quite sure yet of the best API, though.

# we need grid for these manipulations
require(grid)

# convert to gtables
grobs <- lapply(plots, ggplot2::ggplotGrob)

# width of panel is hardcoded, right margin is set to expand
panel_width <- unit(4, "inches")
r_margin_width <- unit(1, "null")

if(getRversion() < "3.3.0"){
  # the following conversions are necessary
  # because there is no `[<-`.unit method
  # so promoting to unit.list allows standard list indexing
  for ( i in 1:length(grobs) )
  {
    grobs[[i]]$widths <- grid:::unit.list(grobs[[i]]$widths)
  }

  panel_width <- grid:::unit.list(panel_width)
  r_margin_width <- grid:::unit.list(r_margin_width)
}

max_widths <- do.call(grid::unit.pmax, lapply(grobs, function(x){x$widths}))

# now assing to all graphs
for ( i in 1:length(grobs) )
{
  grobs[[i]]$widths[1:3] <- max_widths[1:3]   # align y axis
  grobs[[i]]$widths[4] <- panel_width         # set panel size
  grobs[[i]]$widths[6] <- r_margin_width      # set right margin
}

p <- plot_grid(plotlist = grobs, ncol = 1)

save_plot("plot.png", p, base_width = 8, base_aspect_ratio = 2.5, nrow = 3)

[aviast]

Thanks Claus. That seems to be heading in the right direction. I'll need to play around with the plot width to avoid the years running into each other and it looks like the bottom chart is not aligned with the top two.

[aviast]

BTW, here is my data as extracted from the PDF.

library(cowplot)
library(plyr)

df <- structure(list(Measure = c("Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures", "Incidents", "Serious incidents", 
"Serious injury accidents", "Fatal accidents", "Total accidents", 
"Serious injuries", "Fatalities", "Accidents per million departures", 
"Fatal accidents per million departures"), Description = c("Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of people involved", "Number of people involved", "Rate of aircraft involved", 
"Rate of aircraft involved", "Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of people involved", "Number of people involved", 
"Rate of aircraft involved", "Rate of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of people involved", "Number of people involved", "Rate of aircraft involved", 
"Rate of aircraft involved", "Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of people involved", "Number of people involved", 
"Rate of aircraft involved", "Rate of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of people involved", "Number of people involved", "Rate of aircraft involved", 
"Rate of aircraft involved", "Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of people involved", "Number of people involved", 
"Rate of aircraft involved", "Rate of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of people involved", "Number of people involved", "Rate of aircraft involved", 
"Rate of aircraft involved", "Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of people involved", "Number of people involved", 
"Rate of aircraft involved", "Rate of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of people involved", "Number of people involved", "Rate of aircraft involved", 
"Rate of aircraft involved", "Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of aircraft involved", 
"Number of aircraft involved", "Number of people involved", "Number of people involved", 
"Rate of aircraft involved", "Rate of aircraft involved"), Year = structure(c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 
6L, 6L, 6L, 6L, 6L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 8L, 8L, 
8L, 8L, 8L, 8L, 8L, 8L, 8L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 
10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L), .Label = c("2005", 
"2006", "2007", "2008", "2009", "2010", "2011", "2012", "2013", 
"2014"), class = "factor"), Count = c(3332, 32, 2, 2, 12, 2, 
18, 9.2, 1.5, 3081, 16, 0, 1, 12, 0, 2, 9.5, 0.8, 3152, 47, 1, 
2, 23, 1, 2, 17.5, 1.5, 3337, 52, 3, 3, 29, 15, 6, 22.1, 2.3, 
3162, 27, 4, 0, 14, 6, 0, 11, 0, 3477, 37, 2, 1, 23, 2, 2, 16.6, 
0.7, 4002, 28, 2, 2, 21, 2, 2, 14.9, 1.4, 4222, 47, 2, 1, 14, 
2, 1, 9.5, 0.7, 4402, 54, 2, 2, 15, 4, 3, 10.4, 1.4, 4308, 37, 
5, 0, 27, 7, 0, NA, NA)), row.names = c(NA, -90L), .Names = c("Measure", 
"Description", "Year", "Count"), class = "data.frame")

PLOT <- dlply(df, .(Description), function(DATA) {
  ggplot(DATA, aes(x = Year, y = Count, group = Measure, colour = Measure)) +
    geom_line() +
    theme(legend.position = "right",
          legend.justification = c(0,0),
          legend.title = element_blank()) +
    background_grid(major = "xy", minor = "none")
})

plot_grid(plotlist = PLOT, align = "v", ncol = 1)