init

R/rules.R

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+#' Create a Paint Rule
+#'
+#' @description
+#' Creates a paint rule that specifies how to render features from a
+#' particular data layer. Paint rules control the visual appearance of
+#' polygon, line, and point features.
+#'
+#' @param dataLayer Character. The name of the data layer in the vector
+#'   tile source (e.g., "water", "earth", "roads").
+#' @param symbolizer A symbolizer object created with one of the symbolizer
+#'   functions (e.g., \code{\link{pmPolygonSymbolizer}},
+#'   \code{\link{pmLineSymbolizer}}).
+#' @param minzoom Numeric. Minimum zoom level at which this rule applies.
+#'   Default is NULL (applies at all zoom levels).
+#' @param maxzoom Numeric. Maximum zoom level at which this rule applies.
+#'   Default is NULL (applies at all zoom levels).
+#' @param filter Character. A JavaScript expression string that filters
+#'   features. The expression has access to \code{zoom} and \code{feature}
+#'   variables. Default is NULL (no filter).
+#'
+#' @return A list representing the paint rule configuration.
+#'
+#' @examples
+#' # Render water polygons in blue
+#' pmPaintRule("water", pmPolygonSymbolizer(fill = "steelblue"))
+#'
+#' # Render roads with zoom-dependent visibility
+#' pmPaintRule("roads", pmLineSymbolizer(color = "gray", width = 2),
+#'             minzoom = 10)
+#'
+#' # Filter to only show highways
+#' pmPaintRule("roads",
+#'             pmLineSymbolizer(color = "orange", width = 4),
+#'             filter = "feature.props.kind === 'highway'")
+#'
+#' @export
+pmPaintRule <- function(dataLayer,
+                         symbolizer,
+                         minzoom = NULL,
+                         maxzoom = NULL,
+                         filter = NULL) {
+  rule <- list(
+    dataLayer = dataLayer,
+    symbolizer = symbolizer
+  )
+
+  if (!is.null(minzoom)) rule$minzoom <- minzoom
+  if (!is.null(maxzoom)) rule$maxzoom <- maxzoom
+  if (!is.null(filter)) rule$filter <- filter
+
+  rule
+}
+
+
+#' Create a Label Rule
+#'
+#' @description
+#' Creates a label rule that specifies how to render text labels for
+#' features from a particular data layer. Label rules control text
+#' placement and styling, with automatic collision detection.
+#'
+#' @param dataLayer Character. The name of the data layer in the vector
+#'   tile source (e.g., "places", "roads").
+#' @param symbolizer A text symbolizer object created with one of
+#'   \code{\link{pmTextSymbolizer}}, \code{\link{pmCenteredTextSymbolizer}},
+#'   \code{\link{pmLineLabelSymbolizer}}, or \code{\link{pmShieldSymbolizer}}.
+#' @param minzoom Numeric. Minimum zoom level at which this rule applies.
+#'   Default is NULL (applies at all zoom levels).
+#' @param maxzoom Numeric. Maximum zoom level at which this rule applies.
+#'   Default is NULL (applies at all zoom levels).
+#' @param filter Character. A JavaScript expression string that filters
+#'   features. Default is NULL (no filter).
+#'
+#' @return A list representing the label rule configuration.
+#'
+#' @examples
+#' # Label cities
+#' pmLabelRule("places",
+#'             pmCenteredTextSymbolizer(font = "14px Arial",
+#'                                      fill = "black",
+#'                                      stroke = "white",
+#'                                      width = 2))
+#'
+#' # Label streets along their paths
+#' pmLabelRule("roads",
+#'             pmLineLabelSymbolizer(font = "11px Arial",
+#'                                   fill = "#333"),
+#'             minzoom = 14)
+#'
+#' @export
+pmLabelRule <- function(dataLayer,
+                         symbolizer,
+                         minzoom = NULL,
+                         maxzoom = NULL,
+                         filter = NULL) {
+  rule <- list(
+    dataLayer = dataLayer,
+    symbolizer = symbolizer
+  )
+
+  if (!is.null(minzoom)) rule$minzoom <- minzoom
+  if (!is.null(maxzoom)) rule$maxzoom <- maxzoom
+  if (!is.null(filter)) rule$filter <- filter
+
+  rule
+}