R/theme_tscv.R

In ahaeusser/tscv: Functions and utilities for tidy time series forecasting and time series cross-validation

#' @title Custom ggplot2 theme for tscv package
#'
#' @description Custom ggplot2 theme for tscv package.
#'
#' @param base_size Base font size.
#' @param base_family Base font family.
#' @param base_line_size Base size for "line" elements.
#' @param base_rect_size Base size for "rect" elements.
#'
#' @export

theme_tscv <- function(base_size = 11,
                       base_family = "",
                       base_line_size = base_size / 22,
                       base_rect_size = base_size / 22) {

  # The half-line (base-fontsize / 2) sets up the basic vertical
  # rhythm of the theme. Most margins will be set to this value.
  # However, when we work with relative sizes, we may want to multiply
  # `half_line` with the appropriate relative size. This applies in
  # particular for axis tick sizes. And also, for axis ticks and
  # axis titles, `half_size` is too large a distance, and we use `half_size/2`
  # instead.
  half_line <- base_size / 2

  # Throughout the theme, we use three font sizes, `base_size` (`rel(1)`)
  # for normal, `rel(0.8)` for small, and `rel(1.2)` for large.

  ggplot2::theme(
    # Elements in this first block aren't used directly, but are inherited by others
    line = ggplot2::element_line(
      colour     = "black",
      size       = base_line_size,
      linetype   = 1,
      lineend    = "butt"
      ),
    rect = ggplot2::element_rect(
      fill       = "white",
      colour     = "black",
      size       = base_rect_size,
      linetype   = 1
      ),
    text = ggplot2::element_text(
      family     = base_family,
      face       = "plain",
      colour     = "black",
      size       = base_size,
      lineheight = 0.9,
      hjust      = 0.5,
      vjust      = 0.5,
      angle      = 0,
      margin     = ggplot2::margin(),
      debug      = FALSE
    ),

    axis.line                  = ggplot2::element_blank(),
    axis.line.x                = NULL,
    axis.line.y                = NULL,
    axis.text                  = ggplot2::element_text(size = ggplot2::rel(0.8), colour = "grey30"),
    axis.text.x                = ggplot2::element_text(margin = ggplot2::margin(t = 0.8 * half_line / 2), vjust = 1),
    axis.text.x.top            = ggplot2::element_text(margin = ggplot2::margin(b = 0.8 * half_line / 2), vjust = 0),
    axis.text.y                = ggplot2::element_text(margin = ggplot2::margin(r = 0.8 * half_line / 2), hjust = 1),
    axis.text.y.right          = ggplot2::element_text(margin = ggplot2::margin(l = 0.8 * half_line / 2), hjust = 0),
    axis.ticks                 = ggplot2::element_blank(),
    axis.ticks.length          = ggplot2::unit(half_line / 2, "pt"),
    axis.ticks.length.x        = NULL,
    axis.ticks.length.x.top    = NULL,
    axis.ticks.length.x.bottom = NULL,
    axis.ticks.length.y        = NULL,
    axis.ticks.length.y.left   = NULL,
    axis.ticks.length.y.right  = NULL,
    axis.title.x               = ggplot2::element_text(margin = ggplot2::margin(t = half_line / 2), vjust = 1),
    axis.title.x.top           = ggplot2::element_text(margin = ggplot2::margin(b = half_line / 2), vjust = 0),
    axis.title.y               = ggplot2::element_text(angle = 90, margin = ggplot2::margin(r = half_line / 2), vjust = 1),
    axis.title.y.right         = ggplot2::element_text(angle = -90, margin = ggplot2::margin(l = half_line / 2), vjust = 0),

    legend.background          = ggplot2::element_blank(),
    legend.spacing             = ggplot2::unit(2 * half_line, "pt"),
    legend.spacing.x           = NULL,
    legend.spacing.y           = NULL,
    legend.margin              = ggplot2::margin(half_line, half_line, half_line, half_line),
    legend.key                 = ggplot2::element_blank(),
    legend.key.size            = ggplot2::unit(1.2, "lines"),
    legend.key.height          = NULL,
    legend.key.width           = NULL,
    legend.text                = ggplot2::element_text(size = ggplot2::rel(0.8)),
    legend.text.align          = NULL,
    legend.title               = ggplot2::element_blank(),
    legend.title.align         = NULL,
    legend.position            = "bottom",
    legend.direction           = NULL,
    legend.justification       = "center",
    legend.box                 = NULL,
    legend.box.margin          = ggplot2::margin(0, 0, 0, 0, "cm"),
    legend.box.background      = ggplot2::element_blank(),
    legend.box.spacing         = ggplot2::unit(2 * half_line, "pt"),

    panel.background           = ggplot2::element_blank(),
    panel.border               = ggplot2::element_blank(),
    panel.grid.major           = ggplot2::element_line(color = "grey92", size = 0.25),
    panel.grid.minor           = ggplot2::element_line(color = "grey97", size = 0.1),
    panel.spacing              = ggplot2::unit(half_line, "pt"),
    panel.spacing.x            = NULL,
    panel.spacing.y            = NULL,
    panel.ontop                = FALSE,

    strip.background           = element_rect(colour = "grey97", fill = "grey97"),
    strip.text                 = ggplot2::element_text(colour = "grey10", size = ggplot2::rel(0.8), margin = ggplot2::margin(0.8 * half_line, 0.8 * half_line, 0.8 * half_line, 0.8 * half_line)),
    strip.text.x               = NULL,
    strip.text.y               = ggplot2::element_text(angle = -90),
    strip.placement            = "inside",
    strip.placement.x          = NULL,
    strip.placement.y          = NULL,
    strip.switch.pad.grid      = ggplot2::unit(half_line / 2, "pt"),
    strip.switch.pad.wrap      = ggplot2::unit(half_line / 2, "pt"),

    plot.background            = ggplot2::element_blank(),
    plot.title                 = ggplot2::element_text(size = ggplot2::rel(1.2), hjust = 0, vjust = 1, margin = ggplot2::margin(b = half_line), face = "bold"),
    plot.subtitle              = ggplot2::element_text(hjust = 0, vjust = 1, margin = ggplot2::margin(b = half_line), color = "grey40", face = "plain"),
    plot.caption               = ggplot2::element_text(size = ggplot2::rel(0.6), hjust = 1, vjust = 1, margin = ggplot2::margin(t = half_line), color = "gray40"),
    plot.tag                   = ggplot2::element_text(size = ggplot2::rel(1.2), hjust = 0.5, vjust = 0.5),
    plot.tag.position          = 'topleft',
    plot.margin                = ggplot2::margin(half_line, half_line, half_line, half_line),

    complete                   = TRUE
  )
}