retrain color defaults in subplot. fixes #724

Author: cpsievert

R/plotly_build.R

@@ -437,6 +437,8 @@ map_color <- function(traces, title = "", na.color = "transparent") {
     col <- color[[i]] %||% colorDefaults[[idx]]
     alpha <- traces[[i]]$alpha %||% 1
     rgb <- toRGB(col, alpha)
+    # we need some way to identify pre-specified defaults in subplot to retrain them
+    if (is.null(color[[i]])) attr(rgb, "defaultAlpha") <- alpha
     obj <- if (hasLine[[i]]) "line" else if (hasMarker[[i]]) "marker" else if (hasText[[i]]) "textfont"
     traces[[i]][[obj]] <- modify_list(list(color = rgb), traces[[i]][[obj]])
     traces[[i]][[obj]] <- modify_list(list(fillcolor = rgb), traces[[i]][[obj]])

R/subplots.R

@@ -223,6 +223,9 @@ subplot <- function(..., nrows = 1, widths = NULL, heights = NULL, margin = 0.02
     data = Reduce(c, traces),
     layout = Reduce(modify_list, c(xAxes, rev(yAxes)))
   )
+  # retrain default coloring
+  p$data <- retrain_color_defaults(p$data)
+  
   # reposition shapes and annotations
   annotations <- Map(reposition, annotations, split(domainInfo, seq_along(plots)))
   shapes <- Map(reposition, shapes, split(domainInfo, seq_along(plots)))
@@ -333,3 +336,19 @@ reposition <- function(obj, domains) {
   }
   obj
 }
+
+
+retrain_color_defaults <- function(traces) {
+  colorDefaults <- traceColorDefaults()
+  for (i in seq_along(traces)) {
+    # https://github.com/plotly/plotly.js/blob/c83735/src/plots/plots.js#L58
+    idx <- i %% length(colorDefaults) + i %/% length(colorDefaults)
+    newDefault <- colorDefaults[[idx]]
+    for (j in c("marker", "line", "text")) {
+      alpha <- attr(traces[[i]][[j]][["color"]], "defaultAlpha")
+      if (is.null(alpha)) next
+      traces[[i]][[j]][["color"]] <- toRGB(colorDefaults[[idx]], alpha)
+    }
+  }
+  traces
+}