multiarea chart in lattice

Question

I am pushing lattice to its limits.

Consider this example

tibble(time = c(ymd('2019-01-01'),
                      ymd('2019-01-02'),
                      ymd('2019-01-03'),
                      ymd('2019-01-01'),
                      ymd('2019-01-02'),
                      ymd('2019-01-03'),
                      ymd('2019-01-01'),
                      ymd('2019-01-02'),
                      ymd('2019-01-03')),
             variable = c('a','a','a','b','b','b', 'c','c','c'),
             value = c(1,2,3,0,0,2,2,4,3)) %>% 
  ggplot(aes(x = time, y = value, fill = variable)) + geom_area()

Using the nice solution in how to create a stacked area chart in lattice? does not work here, perhaps because we have multiple areas.

Can we still do it with lattice? Thanks!

Answer 1

library(dplyr)
library(lubridate)
library(lattice)
library(latticeExtra)

df1 <- tibble(time = c(ymd('2019-01-01'),
                       ymd('2019-01-02'),
                       ymd('2019-01-03'),
                       ymd('2019-01-01'),
                       ymd('2019-01-02'),
                       ymd('2019-01-03'),
                       ymd('2019-01-01'),
                       ymd('2019-01-02'),
                       ymd('2019-01-03')),
              variable = c('a','a','a','b','b','b', 'c','c','c'),
              value = c(1,2,3,0,0,2,2,4,3))

df2 <- df1 %>% group_by(time) %>% mutate(val=cumsum(value))

xyplot(val~time, df2, group=variable,
       panel=function(x,y,...){
         panel.xyarea(x,y,...)
         panel.xyplot(x,y,...)},
       alpha=c(0.9,0.6,0.3)) 

^{Created on 2019-06-13 by the reprex package (v0.3.0)}