@@ -3,6 +3,7 @@
 S3method(ggplot_add,scale_auto_ipea)
 S3method(ggplot_add,scale_ipea_color)
 S3method(ggplot_add,scale_ipea_fill)
+export(ipea_contrast_color)
 export(ipea_label_size)
 export(ipea_pal)
 export(save_ipeaplot)
 
@@ -5,6 +5,9 @@
   * Fixed `save_ipeaplot()` silently reporting success when a Cairo-based device fails to write a file; it now errors with a clear message.
   * New palettes `"NT"` and `"TD"`, based on the cover, section-title and chart colours of two Ipea editorial series (Nota Tecnica and Texto para Discussao). `scale_color_ipea()`/`scale_fill_ipea()` switch automatically to their qualitative 12-colour variant for discrete data.
   * Fixed a color-accuracy bug in `ipea_palette()` affecting every palette: an incorrect string offset silently forced the low nibble of the blue channel to `F` in all generated colours.
+  * `theme_ipea()`: default `legend.position` changed from `"right"` to `"bottom"`, matching the Ipea Editorial Manual guidelines.
+  * `theme_ipea()`: `geom_point()` layers in line charts (i.e. plots that also have a `geom_line()`/`geom_path()`/`geom_step()` layer) now default to a solid square marker (`shape = 15`), per the Ipea Editorial Manual guidelines. Does not affect scatter plots or a shape already set by the user.
+  * New function `ipea_contrast_color()`: given one or more fill/background colours, returns `"white"` or `"black"`, whichever is more readable, for labels drawn over bars/points per the editorial guidelines.
 
 # ipeaplot 0.5.4
   * Fixed the vignette to address issues with geobr.
 
@@ -0,0 +1,42 @@
+#' @title Contrasting text colour for labels drawn over a fill colour
+#'
+#' @description Given one or more fill/background colours, returns `"white"`
+#' or `"black"`, whichever gives better contrast against that background.
+#' Useful for value labels drawn inside bars or over points/lines, matching
+#' the Ipea editorial guidelines for graphics, which alternate the colour of
+#' data labels according to how dark the colour behind them is. See
+#' <https://www.ipea.gov.br/manualeditorial/padroes/padroes-grafico-visuais/ilustracoes-pi.html>.
+#'
+#' @param background A character vector of colours (hex codes or R colour
+#'        names) used as the fill/background behind the label.
+#'
+#' @return A character vector the same length as `background`, containing
+#'         `"white"` or `"black"`.
+#' @export
+#' @family ggplot2 theme functions
+#'
+#' @examples
+#' ipea_contrast_color(c("#29112F", "#D2A0C9"))
+#'
+#' library(ggplot2)
+#' df <- data.frame(grupo = c("A", "B"), valor = c(22.6, 4.7),
+#'                   cor = c("#29112F", "#D2A0C9"))
+#' ggplot(df, aes(grupo, valor, fill = cor, label = valor)) +
+#'   geom_col() +
+#'   geom_text(aes(color = ipea_contrast_color(cor)), size = ipea_label_size(),
+#'             fontface = "bold") +
+#'   scale_fill_identity() +
+#'   scale_color_identity() +
+#'   theme_ipea()
+ipea_contrast_color <- function(background) {
+  rgb_mat <- grDevices::col2rgb(background) / 255
+
+  # Luminancia relativa (WCAG): converte cada canal sRGB para linear antes de
+  # ponderar pela sensibilidade do olho humano a cada cor.
+  linear_channel <- function(ch) ifelse(ch <= 0.03928, ch / 12.92, ((ch + 0.055) / 1.055)^2.4)
+  linear_rgb <- apply(rgb_mat, 2, linear_channel)
+  luminance <- 0.2126 * linear_rgb[1, ] + 0.7152 * linear_rgb[2, ] + 0.0722 * linear_rgb[3, ]
+
+  # 0.179 e o limiar em que o contraste com texto preto e branco se equivale.
+  ifelse(luminance > 0.179, "black", "white")
+}
@@ -11,8 +11,8 @@
 #'        axis text will be displayed in black; otherwise, they will
 #'        be hidden.
 #' @param legend.position A character vector specifying the position of the
-#'        legend. Valid options are `"right"` (default), `"left"`, `"top"`, and
-#'        `"bottom"`.
+#'        legend. Valid options are `"bottom"` (default, matching the Ipea
+#'        editorial guidelines), `"right"`, `"left"`, and `"top"`.
 #' @param grid.adjust Defines whether the grid lines should be `"horizontal"`
 #'       (default) or `"vertical"`.
 #' @param x_breaks Numeric. The number of breaks on the x-axis
@@ -48,7 +48,7 @@
 
 theme_ipea <- function(axis_lines = 'full',
                        axis_values = TRUE,
-                       legend.position = 'right',
+                       legend.position = 'bottom',
                        grid.adjust = 'horizontal',
                        x_breaks = NULL, # Valor padrão definido como NULL
                        y_breaks = NULL, # Valor padrão definido como NULL
@@ -509,6 +509,31 @@ ggplot_add.scale_auto_ipea <- function(object, plot, object_name, ...) {
 
   }
 
+  # Marcadores quadrados: o Manual Editorial do Ipea usa marcador quadrado
+  # solido nos pontos de graficos de linha (ver referencia no topo do
+  # arquivo). Só aplicado quando o plot tem uma camada de linha (geom_line/
+  # geom_path/geom_step) junto com a de pontos, para não afetar graficos de
+  # dispersao (scatter) puros. Não sobrescreve um shape ja definido (fixo ou
+  # mapeado) pelo usuario.
+  layer_fn_name <- function(layer) {
+    call_str <- paste(deparse(layer$constructor), collapse = " ")
+    sub("\\s*\\(.*$", "", trimws(call_str))
+  }
+  layer_fns <- vapply(plot$layers, layer_fn_name, character(1))
+  has_line_layer <- any(layer_fns %in% c("geom_line", "geom_path", "geom_step"))
+
+  if (has_line_layer) {
+    for (i in seq_along(plot$layers)) {
+      is_point_layer <- layer_fns[i] == "geom_point"
+      shape_already_set <- "shape" %in% names(c(plot$mapping, plot$layers[[i]]$mapping)) ||
+        !is.null(plot$layers[[i]]$aes_params$shape)
+
+      if (is_point_layer && !shape_already_set) {
+        plot$layers[[i]]$aes_params$shape <- 15
+      }
+    }
+  }
+
   plot <- plot + theme
 
 
 
@@ -55,7 +55,7 @@ fig_raw <- ggplot(data = mtcars, aes(x = hp , y = mpg, color = cyl)) +
 # Adicionando os padrões do Ipea
 fig_ipea <- fig_raw +
       scale_color_ipea() +
-      theme_ipea()
+      theme_ipea(legend.position = "right")
 
 # Painel lado a lado: com (esquerda) e sem (direita) o ipeaplot
 fig_panel <- fig_ipea | fig_raw