R/utils.R

In hongyuanjia/ggpsychro: A 'ggplot2' Extension for Making Pyschrometric Charts

is.waive <- function(x) inherits(x, "waiver")

# new_data_frame {{{
# copied from ggplot2/R/performance.R
# Fast data.frame constructor and indexing
# No checking, recycling etc. unless asked for
new_data_frame <- function(x = list(), n = NULL) {
    if (length(x) != 0 && is.null(names(x))) {
        stop("Elements must be named")
    }
    lengths <- vapply(x, length, integer(1))
    if (is.null(n)) {
        n <- if (length(x) == 0 || min(lengths) == 0) 0 else max(lengths)
    }
    for (i in seq_along(x)) {
        if (lengths[i] == n) next
        if (lengths[i] != 1) {
            stop("Elements must equal the number of rows or 1")
        }
        x[[i]] <- rep(x[[i]], n)
    }

    class(x) <- "data.frame"

    attr(x, "row.names") <- .set_row_names(n)
    x
}
# }}}

# with_units {{{
#' @importFrom psychrolib SetUnitSystem
with_units <- function (units, expr) {
    psychrolib::SetUnitSystem(units)

    on.exit(psy_op$UNITS <- NA_character_, add = TRUE)

    force(expr)
}
# }}}
# encode_units {{{
encode_units <- function (units) {
    switch(units, "SI" = 1L, "IP" = 2L, stop("'units' can only be either 'SI' or 'IP'."))
}
# }}}
# decode_units {{{
decode_units <- function (code) {
    c("SI", "IP")[code]
}
# }}}

# bid_conv {{{
# bidirectional conversion
bid_conv <- function (x, to) {
    switch(to,
        "F" = get_f_from_c(x),
        "C" = get_c_from_f(x),
        "Gr" = get_gr_from_g(x),
        "G" = get_g_from_gr(x)
    )
}
get_f_from_c <- function (x) x * 9. / 5. + 32.
get_c_from_f <- function (x) (x - 32) * 5. / 9.
get_g_from_gr <- function (x) x / 7.
get_gr_from_g <- function (x) x * 7.
# }}}

# dist_euclid {{{
dist_euclid <- function (x, y, xend, yend) {
    sqrt((xend - x) ^2 + (yend - y)^2)
}
# }}}

# rep_dataframe {{{
rep_dataframe <- function (df, n) {
    do.call(rbind, replicate(n, df, simplify = FALSE))
}
# }}}

# The units of humidity ratio is lb_H2O lb_Air-1 [IP] or kg_H2O kg_Air-1 [SI],
# but for Psychrometric Chart, we use gr_H2O lb_Air-1 [IP] or g_H2O kg_Air-1
# [SI]. Should amplify before plotting or do reversely during calculation
# amplify_hum {{{
amplify_hum <- function (hum, units) {
    if (units == "SI") {
        hum * 1000.0
    } else {
        hum * 7000.0
    }
}
# }}}
# narrow_hum {{{
narrow_hum <- function (hum, units) {
    if (units == "SI") {
        hum / 1000.0
    } else {
        hum / 7000.0
    }
}
# }}}

# The units of enthalpy is J kg-1 [SI], but for Psychrometric Chart, we use kJ
# kg-1 [SI]. Should amplify before plotting or do reversely during calculation
# amplify_enth {{{
amplify_enth <- function (enth, units) {
    if (units == "SI") {
        enth * 1000.0
    } else {
        enth
    }
}
# }}}
# narrow_enth {{{
narrow_enth <- function(enth, units) {
    if (units == "SI") {
         enth / 1000.0
    } else {
         enth
    }
}
# }}}

# slope {{{
slope <- function (x, y, xend, yend) {
    (yend - y) / (xend - x)
}
# }}}
# adopted from thomasp85/ggraph/R/utils.R
# line_angle {{{
line_angle <- function(x, y, xend, yend, degrees = TRUE) {
    angles <- atan(slope(x, y, xend, yend))
    angles[is.nan(angles)] <- 2 * pi
    angles[angles < 0] <- angles[angles < 0] + 2 * pi
    if (degrees) {
        angles * 360 / (2 * pi)
    } else {
        angles
    }
}
# }}}