[WIP] Fix point shape mismatch between plot and legend

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: gglite
 Title: Lightweight Data Visualization via the Grammar of Graphics
-Version: 0.0.6
+Version: 0.0.7
 Authors@R: person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name",
     comment = c(ORCID = "0000-0003-0645-5666"))
 Description: A lightweight R interface to the AntV G2 JavaScript visualization

R/render.R

@@ -31,6 +31,22 @@ build_config = function(chart) {
 
   # Chart-wide config
   if (length(chart$scales)) config$scale = chart$scales
+
+  # Work around G2 legend bug: when shape is the only categorical encoding
+  # (no color), the legend renders wrong shapes. Explicitly set the shape
+  # scale range to exactly N shapes so ordinal wrapping is correct.
+  shape_col = chart$aesthetics$shape
+  if (is.character(shape_col) && length(shape_col) == 1 &&
+      !is.null(chart$data) && shape_col %in% names(chart$data) &&
+      is.null(chart$scales$shape$range)) {
+    n = length(unique(chart$data[[shape_col]]))
+    shapes = c('point', 'plus', 'diamond', 'square', 'triangle',
+      'hexagon', 'cross', 'bowtie')
+    if (is.null(config$scale)) config$scale = list()
+    config$scale$shape = modifyList(
+      as.list(config$scale$shape), list(range = rep_len(shapes, n))
+    )
+  }
   if (!is.null(chart$coords)) config$coordinate = chart$coords
   if (length(chart$interactions)) config$interaction = chart$interactions
   if (length(chart$axes)) config$axis = chart$axes

tests/testit/test-gglite.R

@@ -265,6 +265,24 @@ assert('slider_x() and scrollbar_y() are shortcuts', {
   (isTRUE(chart$scrollbars$y))
 })
 
+# build_config() auto-sets shape scale range to fix legend mismatch
+assert('build_config() sets shape scale range when shape maps to column', {
+  chart = g2(iris, x = 'Sepal.Width', y = 'Sepal.Length',
+    shape = 'Species') |> mark_point()
+  config = build_config(chart)
+  # 3 unique Species -> range of length 3
+  (length(config$scale$shape$range) %==% 3L)
+  (config$scale$shape$range %==% c('point', 'plus', 'diamond'))
+})
+
+assert('build_config() does not override user-set shape range', {
+  chart = g2(iris, x = 'Sepal.Width', y = 'Sepal.Length',
+    shape = 'Species') |> mark_point() |>
+    scale_shape(range = c('circle', 'square', 'triangle'))
+  config = build_config(chart)
+  (config$scale$shape$range %==% c('circle', 'square', 'triangle'))
+})
+
 assert('build_config includes layout options', {
   chart = g2(data.frame(x = 1, y = 2), x = 'x', y = 'y',
     padding = 20, inset = c(5, NA, 5, NA)) |>