#' @export
#' @keywords internal
#' @rdname tmap_internal
tmapGridSymbols = function(shpTM, dt, gp, bbx, facet_row, facet_col, facet_page, id, pane, group, o, ...) {
	args = list(...)
	rc_text = frc(facet_row, facet_col)

	g = get("g", .TMAP_GRID)

	# COPIED FROM tmapGridText -> function
	# calculate native per line
	wIn = g$colsIn[g$cols_facet_ids[facet_col]]
	hIn = g$rowsIn[g$rows_facet_ids[facet_row]]

	wNative = bbx[3] - bbx[1]
	hNative = bbx[4] - bbx[2]

	xIn = wNative / wIn
	yIn = hNative / hIn

	lineIn = convertHeight(unit(1, "lines"), "inch", valueOnly = TRUE)


	res = select_sf(shpTM, dt[!is.na(dt$size), ])
	shp = res$shp
	dt = res$dt

	gp = impute_gp(gp, dt)
	gp = swap_pch_15_20(gp)

	#gp = get_pch_1000p(gp)

	gp = rescale_gp(gp, o$scale_down * o$scale)

	#gp = gp_to_gpar(gp, sel = "all")

	diffAlpha = !any(is.na(c(gp$fill_alpha, gp$col_alpha))) && !(length(gp$fill_alpha) == length(gp$col_alpha) && all(gp$fill_alpha == gp$col_alpha))

	coords = sf::st_coordinates(shp)

	# in case shp is a multipoint (point.per == "segment"), expand gp:
	cp = expand_coords_gp(coords, gp, ndt = nrow(dt))
	coords = cp$coords
	gp = cp$gp

	if (diffAlpha) {
		gp1 = gp_to_gpar(gp, sel = "fill", o = o, type = "symbols")
		gp2 = gp_to_gpar(gp, sel = "col", o = o, type = "symbols")

		grb1 = grid::pointsGrob(x = grid::unit(coords[,1], "native"), y = grid::unit(coords[,2], "native"), pch = gp$shape, size = grid::unit(gp$size, "lines"), gp = gp1, name = paste0("symbols_", id))
		grb2 = grid::pointsGrob(x = grid::unit(coords[,1], "native"), y = grid::unit(coords[,2], "native"), pch = gp$shape, size = grid::unit(gp$size, "lines"), gp = gp2, name = paste0("symbols_borders_", id))
		grb = grid::grobTree(grb1, grb2)
	} else {
		gp = gp_to_gpar(gp, sel = "all", o = o, type = "symbols")

		if (any(!is.na(gp$shape) & gp$shape>999)) {
			shapeLib = get("shapeLib", envir = .TMAP)
			justLib = get("justLib", envir = .TMAP)

			grobs <- lapply(1:length(gp$shape), function(i) {
				shi = gp$shape[[i]]

				just = if (is.na(args$just[1])) c(0.5, 0.5) else args$just
				jst = if (!is.na(shi) && shi>999) {
					js = justLib[[shi-999]]
					if (!is.na(js[1])) {
						js
					} else if (!is.na(args$just[1])) {
						args$just
					} else {
						just
					}
				} else just

				justs.x = jst[1]
				justs.y = jst[2]
				justx = xIn * lineIn * (justs.x-.5)
				justy = yIn * lineIn * (justs.y-.5)



				if (!is.na(shi) && shi>999) {
					size = gp$size[i]*9/10 * args$icon.scale
					lwdid = if (length(gp$lwd) == 1L) 1 else i
					grbs <- gList(shapeLib[[shi-999]])
					gTree(children=grbs, vp=viewport(x=grid::unit(coords[i,1] + justx * size, "native"),
													 y=grid::unit(coords[i,2] + justy * size, "native"),
													 width=unit(size, "lines"),
													 height=unit(size, "lines")))
				} else {
					pointsGrob(x=grid::unit(coords[i,1] + justx * gp$size[i], "native"),
							   y=grid::unit(coords[i,2] + justx * gp$size[i], "native"),
							   size=unit(gp$size[i], "lines"),
							   pch=shi,
							   gp=gp)
				}
			})
			grb = gTree(children=do.call(gList, grobs), name=paste0("symbols_", id))
		} else {
			grb = grid::pointsGrob(x = grid::unit(coords[,1], "native"), y = grid::unit(coords[,2], "native"), pch = gp$shape, size = grid::unit(gp$size, "lines"), gp = gp, name = paste0("symbols_", id))
		}


	}


	gts = get("gts", .TMAP_GRID)
	gt = gts[[facet_page]]

	gt_name = paste0("gt_facet_", rc_text)

	gt = grid::addGrob(gt, grb, gPath = grid::gPath(gt_name))

	gts[[facet_page]] = gt
	assign("gts", gts, envir = .TMAP_GRID)
	NULL

}
