Fix legend rendering for fill=NA aesthetic (#227)

Author: ANAMASGARD

NEWS.md

@@ -1,3 +1,7 @@
+# Changes in version 2025.10.5 (Issue #227)
+
+- Fixed legend rendering for `fill=NA` aesthetic. Previously, legend symbols would incorrectly show solid fill when `fill=NA` was specified. Now `fill=NA` is properly converted to "transparent" before legend compilation, ensuring legend symbols appear hollow as expected. This makes `fill=NA` behave identically to `fill="transparent"`.
+
 # Changes in version 2025.10.3 (PR#240)
 
 - `guide_legend(override.aes)` works in a plot with both color and fill legends.

R/z_animintHelpers.R

@@ -711,9 +711,11 @@ getLegend <- function(mb){
     if (nd != nk) warning("key and data have different number of rows")
     if (!".label" %in% names(key)) return(data.frame()); # if there are no labels, return an empty df.
     data$`.label` <- key$`.label`
-    data <- data[, which(colSums(!is.na(data)) > 0)] # remove cols that are entirely na
+    # Convert colour and fill to RGB BEFORE removing NA columns
+    # This ensures fill=NA gets converted to "transparent" and is not removed
     if("colour" %in% names(data)) data[["colour"]] <- toRGB(data[["colour"]]) # color hex values
     if("fill" %in% names(data)) data[["fill"]] <- toRGB(data[["fill"]]) # fill hex values
+    data <- data[, which(colSums(!is.na(data)) > 0)] # remove cols that are entirely na
     names(data) <- paste0(geom, names(data))# aesthetics by geom
     names(data) <- gsub(paste0(geom, "."), "", names(data), fixed=TRUE) # label isn't geom-specific
     data$label <- paste(data$label) # otherwise it is AsIs.

tests/testthat/test-compiler-legend-fill-na.R

@@ -0,0 +1,92 @@
+library(testthat)
+acontext("legend fill=NA rendering")
+
+test_that("fill=NA is converted to transparent in legend", {
+  # Create a simple plot with fill=NA
+  viz <- animint(
+    fillNA=ggplot()+
+      ggtitle("fill=NA")+
+      geom_point(aes(
+        x, x, color=x),
+        fill=NA,
+        shape=21,
+        size=10,
+        data=data.frame(x=1))
+  )
+  
+  # Compile the visualization
+  info <- animint2dir(viz, open.browser = FALSE)
+  
+  # Read the generated plot.json
+  plot_json <- jsonlite::fromJSON(file.path(info$out.dir, "plot.json"))
+  
+  # Check that the legend entry has pointfill="transparent"
+  legend_entries <- plot_json$plots$fillNA$legend$x$entries
+  expect_equal(nrow(legend_entries), 1)
+  expect_equal(legend_entries$pointfill[1], "transparent")
+})
+
+test_that("fill=NA works the same as fill='transparent'", {
+  # Create two plots - one with fill=NA, one with fill="transparent"
+  viz <- animint(
+    fillNA=ggplot()+
+      ggtitle("fill=NA")+
+      geom_point(aes(
+        x, x, color=x),
+        fill=NA,
+        shape=21,
+        size=10,
+        data=data.frame(x=1)),
+    filltransparent=ggplot()+
+      ggtitle("fill=transparent")+
+      geom_point(aes(
+        x, x, color=x),
+        fill="transparent",
+        shape=21,
+        size=10,
+        data=data.frame(x=1))
+  )
+  
+  # Compile the visualization
+  info <- animint2dir(viz, open.browser = FALSE)
+  
+  # Read the generated plot.json
+  plot_json <- jsonlite::fromJSON(file.path(info$out.dir, "plot.json"))
+  
+  # Check that both legend entries have the same pointfill value
+  fillNA_entry <- plot_json$plots$fillNA$legend$x$entries
+  filltransparent_entry <- plot_json$plots$filltransparent$legend$x$entries
+  
+  expect_equal(fillNA_entry$pointfill[1], "transparent")
+  expect_equal(filltransparent_entry$pointfill[1], "transparent")
+  expect_equal(fillNA_entry$pointfill[1], filltransparent_entry$pointfill[1])
+})
+
+test_that("legend with multiple entries and mixed fill values", {
+  # Create a plot with multiple legend entries, some with NA fill
+  test_data <- data.frame(
+    x = 1:3,
+    y = 1:3,
+    group = c("A", "B", "C")
+  )
+  
+  viz <- animint(
+    plot=ggplot(test_data, aes(x, y, color=group))+
+      geom_point(shape=21, size=5, fill=NA)
+  )
+  
+  # Compile the visualization
+  info <- animint2dir(viz, open.browser = FALSE)
+  
+  # Read the generated plot.json
+  plot_json <- jsonlite::fromJSON(file.path(info$out.dir, "plot.json"))
+  
+  # Check that all legend entries have pointfill="transparent"
+  legend_entries <- plot_json$plots$plot$legend$group$entries
+  expect_equal(nrow(legend_entries), 3)
+  
+  for (i in 1:3) {
+    expect_equal(legend_entries$pointfill[i], "transparent",
+                 info=paste("Entry", i, "should have transparent fill"))
+  }
+})