Convert Character Coordinates into Normalized Parent Coordinates (NPC)

Convert character coordinates to npc units and shift postions to avoid overlaps when grouping is active. If numeric validate npc values.

as_npc(
  value,
  group = 1L,
  step = 0.1,
  margin.npc = 0.05,
  axis = c("xy", "x", "y")
)

as_npcx(value, group = 1L, step = 0.1, margin.npc = 0.05)

as_npcy(value, group = 1L, step = 0.1, margin.npc = 0.05)

Arguments

value: numeric (in [0-1]) or character vector of coordinates. If character, should be one of c('right', 'left', 'bottom', 'top', 'center', 'centre', 'middle').
group: integer ggplot's group id. Used to shift coordinates to avoid overlaps.
step: numeric value in [0-1]. The step size for shifting coordinates in npc units. Considered as horizontal step for x-axis and vertical step for y-axis. For y-axis, the step value can be negative to reverse the order of groups.
margin.npc: numeric [0-1] The margin added towards the nearest plotting area edge when converting character coordinates into npc.
axis: the concerned axis . Should be one of c("xy", "x", "y").

Value

A numeric vector with values in the range [0-1] representing npc coordinates.

Details

the as_npc() function is an adaptation from ggpmisc::compute_npc().

Functions

as_npc(): converts x or y coordinate values into npc. Input values should be numeric or one of the following values c('right', 'left', 'bottom', 'top', 'center', 'centre', 'middle').
as_npcx(): converts x coordinate values into npc. Input values should be numeric or one of the following values c('right', 'left', 'center', 'centre', 'middle'). Wrapper around as_npc(axis = "x").
as_npcy(): converts y coordinate values into npc. Input values should be numeric or one of the following values c( 'bottom', 'top', 'center', 'centre', 'middle'). Wrapper around as_npc(axis = "y").

Examples