R/pattern-both-rose.R

In gridpattern: 'grid' Pattern Grobs

#' Rose curve patterned grobs
#'
#' `grid.pattern_rose()` draws a rose curve pattern onto the graphic device.
#'
#' @inheritParams grid.pattern_circle
#' @inheritParams alphaMaskGrob
#' @param rot Angle to rotate rose (degrees, counter-clockwise).
#' @param frequency The \dQuote{angular frequency} parameter of the rose pattern.
#' @return A grid grob object invisibly.  If `draw` is `TRUE` then also draws to the graphic device as a side effect.
#' @seealso See \url{https://en.wikipedia.org/wiki/Rose_(mathematics)} for more information.
#' @examples
#'   if (capabilities("png") || guess_has_R4.1_features("masks")) {
#'     x_hex <- 0.5 + 0.5 * cos(seq(2 * pi / 4, by = 2 * pi / 6, length.out = 6))
#'     y_hex <- 0.5 + 0.5 * sin(seq(2 * pi / 4, by = 2 * pi / 6, length.out = 6))
#'     gp <- grid::gpar(fill = c("blue", "red", "yellow", "green"), col = "black")
#'     grid.pattern_rose(x_hex, y_hex,
#'                       spacing = 0.15, density = 0.5, angle = 0,
#'                       frequency = 1:4, gp = gp)
#'   }
#'   if (capabilities("png") || guess_has_R4.1_features("masks")) {
#'     grid::grid.newpage()
#'     grid.pattern_rose(x_hex, y_hex,
#'                       spacing = 0.15, density = 0.5, angle = 0,
#'                       frequency = 1/1:4, gp = gp)
#'   }
#'   if (capabilities("png") || guess_has_R4.1_features("masks")) {
#'     grid::grid.newpage()
#'     grid.pattern_rose(x_hex, y_hex,
#'                       spacing = 0.18, density = 0.5, angle = 0,
#'                       frequency = c(3/2, 7/3, 5/4, 3/7), gp = gp)
#'   }
#' @export
grid.pattern_rose <- function(
	x = c(0, 0, 1, 1),
	y = c(1, 0, 0, 1),
	id = 1L,
	...,
	colour = gp$col %||% "grey20",
	fill = gp$fill %||% "grey80",
	angle = 30,
	density = 0.2,
	spacing = 0.05,
	xoffset = 0,
	yoffset = 0,
	units = "snpc",
	frequency = 0.1,
	grid = "square",
	type = NULL,
	subtype = NULL,
	rot = 0,
	alpha = gp$alpha %||% NA_real_,
	linetype = gp$lty %||% 1,
	linewidth = size %||% gp$lwd %||% 1,
	size = NULL,
	use_R4.1_masks = getOption(
		"ggpattern_use_R4.1_masks",
		getOption("ggpattern_use_R4.1_features")
	),
	png_device = NULL,
	res = getOption("ggpattern_res", 72),
	default.units = "npc",
	name = NULL,
	gp = gpar(),
	draw = TRUE,
	vp = NULL
) {
	if (missing(colour) && hasName(l <- list(...), "color")) {
		colour <- l$color
	}
	grid.pattern(
		"rose",
		x,
		y,
		id,
		colour = colour,
		fill = fill,
		angle = angle,
		density = density,
		spacing = spacing,
		xoffset = xoffset,
		yoffset = yoffset,
		units = units,
		scale = scale,
		frequency = frequency,
		grid = grid,
		type = type,
		subtype = subtype,
		rot = rot,
		use_R4.1_masks = use_R4.1_masks,
		png_device = png_device,
		res = res,
		alpha = alpha,
		linetype = linetype,
		linewidth = linewidth,
		default.units = default.units,
		name = name,
		gp = gp,
		draw = draw,
		vp = vp
	)
}

create_pattern_rose <- function(params, boundary_df, aspect_ratio, legend = FALSE) {
	# work in 'bigpts' instead 'npc' / 'snpc' units so we don't worry about the aspect ratio
	default.units <- "bigpts"
	boundary_df <- convert_polygon_df_units(boundary_df, default.units)
	params <- convert_params_units(params, default.units)
	vpm <- get_vp_measurements(default.units)

	spacing <- params$pattern_spacing
	grid <- params$pattern_grid

	# create grid of points large enough to cover viewport no matter the angle
	grid_xy <- get_xy_grid(params, vpm)

	# construct grobs using subsets if certain inputs are vectorized
	fill <- update_alpha(params$pattern_fill, params$pattern_alpha)
	col <- update_alpha(params$pattern_colour, params$pattern_alpha)
	lwd <- params$pattern_linewidth * .pt
	lty <- params$pattern_linetype

	density <- params$pattern_density
	rot <- params$pattern_rot
	frequency <- params$pattern_frequency

	n_par <- max(lengths(list(fill, col, lwd, lty, density, rot, frequency)))

	fill <- rep_len_fill(fill, n_par)
	col <- rep_len(col, n_par)
	lwd <- rep_len(lwd, n_par)
	lty <- rep_len(lty, n_par)
	density <- rep_len(density, n_par)
	rot <- rep_len(rot, n_par)
	frequency <- rep_len(frequency, n_par)

	density_max <- max(density)

	# compute regular polygon relative coordinates which we will center on points
	radius_mult <- switch(grid, hex = 0.578, 0.5)
	radius_max <- radius_mult * spacing * density_max

	# compute pattern matrix of graphical elements (e.g. fill colors)
	if (is.null(params$pattern_type) || is.na(params$pattern_type)) {
		params$pattern_type <- switch(grid, square = "square", "hex")
	}
	m_pat <- get_pattern_matrix(params$pattern_type, params$pattern_subtype, grid_xy, n_par)

	gl <- gList()
	for (i_par in seq(n_par)) {
		radius_outer <- radius_mult * spacing * density[i_par]
		xy_rose <- get_xy_rose(frequency[i_par], params, radius_outer, rot[i_par])
		xy_par <- get_xy_par(grid_xy, i_par, m_pat, grid, spacing)
		if (length(xy_par$x) == 0) {
			next
		}

		# rotate by 'angle'
		xy_par <- rotate_xy(xy_par$x, xy_par$y, params$pattern_angle, vpm$x, vpm$y)

		gp <- gpar(fill = fill[[i_par]], col = col[i_par], lwd = lwd[i_par], lty = lty[i_par])

		name <- paste0("rose.", i_par)
		grob <- points_to_rose_grob(xy_par, xy_rose, gp, default.units, name)
		gl <- append_gList(gl, grob)
	}
	maskee <- gTree(children = gl)
	masker <- convert_polygon_df_to_polygon_grob(
		boundary_df,
		default.units = "bigpts",
		gp = gpar(fill = "white", col = NA, lwd = 0)
	)
	alphaMaskGrob(
		maskee,
		masker,
		use_R4.1_masks = params$pattern_use_R4.1_masks,
		png_device = params$pattern_png_device,
		res = params$pattern_res,
		name = "rose"
	)
}

get_xy_rose <- function(frequency, params, radius_outer, rot) {
	theta <- to_radians(seq.int(from = 0, to = 12 * 360, by = 3))
	x <- radius_outer * cos(frequency * theta) * cos(theta)
	y <- radius_outer * cos(frequency * theta) * sin(theta)
	rose_angle <- rot + params$pattern_angle
	rotate_xy(x, y, rose_angle, 0, 0)
}

points_to_rose_grob <- function(xy_par, xy_rose, gp, default.units, name) {
	points_mat <- as.data.frame(xy_par)
	df_polygon <- as.data.frame(xy_rose)
	l_xy <- lapply(seq(nrow(points_mat)), function(i_r) {
		x0 <- points_mat[i_r, 1]
		y0 <- points_mat[i_r, 2]
		df <- df_polygon
		df$x <- df$x + x0
		df$y <- df$y + y0
		df
	})
	df <- do.call(rbind, l_xy)
	if (is.null(df)) {
		nullGrob()
	} else {
		df$id <- rep(seq(nrow(points_mat)), each = nrow(df_polygon))
		pathGrob(
			x = df$x,
			y = df$y,
			id = df$id,
			default.units = default.units,
			gp = gp,
			name = name
		)
	}
}