Documentation
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Overview ¶
Package scale provides abstractions for scales that map from one domain to another and provide methods for indicating human-readable intervals in the input domain. The most common type of scale is a quantitative scale, such as a linear or log scale, which is captured by the Quantitative interface.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Linear ¶
type Linear struct {
// Min and Max specify the lower and upper bounds of the input
// range. The input range [Min, Max] will be linearly mapped
// to the output domain [0, 1].
Min, Max float64
// Base specifies a base for computing ticks. Ticks will be
// placed at powers of Base; that is at n*Base^l for n ∈ ℤ and
// some integer l. As a special case, a base of 0 alternates
// between ticks at n*10^l and ticks at 5n*10^l.
Base int
// If Clamp is true, the input is clamped to [Min, Max].
Clamp bool
}
type Log ¶
type Log struct {
// Min and Max specify the lower and upper bounds of the input
// range. The input range [Min, Max] will be mapped to the
// output domain [0, 1]. The range [Min, Max] must not include
// 0.
Min, Max float64
// Base specifies the base of the logarithm for computing
// ticks. Typically, ticks will be placed at Base^n for n ∈ ℤ.
Base int
// If Clamp is true, the input is clamped to [Min, Max].
Clamp bool
// contains filtered or unexported fields
}
type QQ ¶
type QQ struct {
Src, Dest Quantitative
}
A QQ maps from a source Quantitative scale to a destination Quantitative scale.
type Quantitative ¶
type Quantitative interface {
// Map maps from a value x in the input range to [0, 1]. If x
// is outside the input range and clamping is enabled, x will
// first be clamped to the input range.
Map(x float64) float64
// Unmap is the inverse of Map. That is, if x is in the input
// range or clamping is disabled, x = Unmap(Map(x)). If
// clamping is enabled and y is outside [0,1], the results are
// undefined.
Unmap(y float64) float64
// SetClamp sets the clamping mode of this scale.
SetClamp(bool)
// Ticks returns a set of at most n major ticks, plus minor
// ticks. These ticks will have "nice" values within the input
// range. Both arrays are sorted in ascending order and minor
// includes ticks in major.
Ticks(n int) (major, minor []float64)
// Nice expands the input range of this scale to "nice" values
// for covering the input range with n major ticks. After
// calling Nice(n), the first and last major ticks returned by
// Ticks(n) will equal the lower and upper bounds of the input
// range.
Nice(n int)
}
A Quantative scale is an invertible function from some continuous input range to an output domain of [0, 1].
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