Fix size and alpha translation for points. Fixes #386

Author: cpsievert

R/trace_generation.R

@@ -590,6 +590,10 @@ geom2trace <- list(
     )
   },
   point=function(data, params){
+    # params contains unique values, but we need _all_ values from the data
+    for (i in names(params)) {
+      if (length(params[[i]]) > 1) params[[i]] <- data[[i]]
+    }
     L <- list(
       x = data$x,
       y = data$y,

tests/testthat/test-ggplot-point.R

@@ -0,0 +1,24 @@
+context("geom_point")
+
+expect_traces <- function(gg, n.traces, name){
+  stopifnot(is.ggplot(gg))
+  stopifnot(is.numeric(n.traces))
+  L <- save_outputs(gg, paste0("smooth-", name))
+  all.traces <- L$data
+  no.data <- sapply(all.traces, function(tr) {
+    is.null(tr[["x"]]) && is.null(tr[["y"]])
+  })
+  has.data <- all.traces[!no.data]
+  expect_equal(length(has.data), n.traces)
+  list(traces=has.data, layout=L$layout)
+}
+
+test_that("geom_point size & alpha translate to a single trace", {
+  gg <- ggplot(mtcars, aes(cyl, wt)) + 
+    geom_point(aes(size = gear, alpha = cyl)) 
+  info <- save_outputs(gg, "point-size-alpha")
+  expect_equal(length(info$data), 1)
+  mkr <- info$data[[1]]$marker
+  expect_equal(length(mkr$size), nrow(mtcars))
+  expect_equal(length(mkr$opacity), nrow(mtcars))
+})