prop {ggvis}

Create a property.

Description

Properties are used to describe the visual properties of marks. You create a single property defintion with prop, and manage sets of named properties with props (which also provides shortcuts for creating the most common kind of properties)

Usage

prop(
  property,
  x,
  scale = NULL,
  offset = NULL,
  mult = NULL,
  env = parent.frame(),
  event = NULL,
  label = NULL
)

is.prop(x)

is.prop_constant(x)

is.prop_variable(x)

is.prop_reactive(x)

Arguments

property

A property, like "x", "x2", "y", "fill", and so on.

x

The value of the property. This can be an atomic vector (a constant), a name or quoted call (a variable), a single-sided formula (a constant or variable depending on its contents), or a delayed reactive (which can be either variable or constant).

scale

If NULL, automatically determine behavior by the kind of value (constant, variable, or reactive). If TRUE use the default scale associated with property. If FALSE, do not scale the value. Otherwise supply a string to select a custom scale. If x is an interactive input, then this defaults to the scale parameter of the input.

offset, mult

Additive and multiplicate pixel offset used to adjust scaled values. These are useful if you want to place labels offset from points.

env

If x is a quoted call this provides the environment in which to look for variables not in the data. You should not need this in ordinary operation.

event

An event to which this property applies. One of "update", "enter", "exit", "hover", "brush".

label

A label for this prop to use for reporting errors.

See Also

props to manage multiple properties and to succintly create the most common types.

Examples

prop("x", 1)
prop("x", ~1)
prop("fill", quote(cyl))
prop("fill", ~cyl)
prop("x", input_slider(0, 100))

# If you have a variable name as a string
var <- "cyl"
prop("x", as.name(var))

# Use a custom scale
prop("y", quote(cyl), scale = "y-2")

# Don't scale variable (i.e. it already makes sense in the visual space)
prop("fill", ~colour, scale = FALSE)

# Use a constant, but scaled
prop("x", 5, scale = TRUE)

# Use other events
prop("y", quote(cyl), scale = "y-2")