58 lines
1.9 KiB
Go
58 lines
1.9 KiB
Go
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package scale
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// A Quantative scale is an invertible function from some continuous
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// input domain to an output range of [0, 1].
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type Quantitative interface {
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// Map maps from a value x in the input domain to [0, 1]. If x
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// is outside the input domain and clamping is enabled, x will
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// first be clamped to the input domain.
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Map(x float64) float64
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// Unmap is the inverse of Map. That is, if x is in the input
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// domain or clamping is disabled, x = Unmap(Map(x)). If
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// clamping is enabled and y is outside [0,1], the results are
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// undefined.
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Unmap(y float64) float64
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// SetClamp sets the clamping mode of this scale.
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SetClamp(bool)
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// Ticks returns major and minor ticks that satisfy the
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// constraints given by o. These ticks will have "nice" values
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// within the input domain. Both arrays are sorted in
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// ascending order and minor includes ticks in major.
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Ticks(o TickOptions) (major, minor []float64)
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// Nice expands the input domain of this scale to "nice"
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// values for covering the input domain satisfying the
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// constraints given by o. After calling Nice(o), the first
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// and last major ticks returned by Ticks(o) will equal the
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// lower and upper bounds of the input domain.
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Nice(o TickOptions)
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// A Quantitative scale is also a Ticker.
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Ticker
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}
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// A QQ maps from a source Quantitative scale to a destination
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// Quantitative scale.
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type QQ struct {
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Src, Dest Quantitative
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}
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// Map maps from a value x in the source scale's input domain to a
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// value y in the destination scale's input domain.
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func (q QQ) Map(x float64) float64 {
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return q.Dest.Unmap(q.Src.Map(x))
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}
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// Unmap maps from a value y in the destination scale's input domain to
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// a value x in the source scale's input domain.
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func (q QQ) Unmap(x float64) float64 {
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return q.Src.Unmap(q.Dest.Map(x))
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}
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