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require 'es6-shim'
vows = require 'vows'
assert = require 'assert'
chroma = require '../chroma'
vows
.describe('Testing bezier interpolation')
.addBatch
'simple two color linear interpolation':
topic: -> chroma.interpolate.bezier ['white', 'black']
'starts from white': (topic) -> assert.equal topic(0).hex(), '#ffffff'
'ends in black': (topic) -> assert.equal topic(1).hex(), '#000000'
'center is grey': (topic) -> assert.equal topic(0.5).hex(), '#777777'
'three color quadratic bezier interpolation':
topic: -> chroma.interpolate.bezier ['white', 'red', 'black']
'starts from white': (topic) -> assert.equal topic(0).hex(), '#ffffff'
'ends in black': (topic) -> assert.equal topic(1).hex(), '#000000'
'center is a greyish red': (topic) -> assert.equal topic(0.5).hex(), '#c45c44'
'four color cubic bezier interpolation':
topic: -> chroma.interpolate.bezier ['white', 'yellow', 'red', 'black']
'starts from white': (topic) -> assert.equal topic(0).hex(), '#ffffff'
'ends in black': (topic) -> assert.equal topic(1).hex(), '#000000'
'1st quarter': (topic) -> assert.equal topic(0.25).hex(), '#ffe085'
'center': (topic) -> assert.equal topic(0.5).hex(), '#e69735'
'3rd quarter': (topic) -> assert.equal topic(0.75).hex(), '#914213'
'five color diverging quadratic bezier interpolation':
topic: -> chroma.interpolate.bezier ['darkred', 'orange', 'snow', 'lightgreen', 'royalblue']
'starts from darkred': (topic) -> assert.equal topic(0).hex(), '#8b0000'
'ends in royalblue': (topic) -> assert.equal topic(1).hex(), '#4169e1'
'center is snow': (topic) -> assert.equal topic(0.5).hex(), '#fffafa'
'1st quarter': (topic) -> assert.equal topic(0.25).hex(), '#e9954e'
'3rd quarter': (topic) -> assert.equal topic(0.75).hex(), '#a6cfc1'
'using bezier in a chroma.scale':
topic: ->
bez = chroma.interpolate.bezier ['darkred', 'orange', 'snow', 'lightgreen', 'royalblue']
chroma.scale(bez).domain([0,1],5).out('hex')
'starts from darkred': (topic) -> assert.equal topic(0), '#8b0000'
'ends in royalblue': (topic) -> assert.equal topic(1), '#4169e1'
'center is snow': (topic) -> assert.equal topic(0.5), '#fffafa'
'1st quarter': (topic) -> assert.equal topic(0.25), '#e9954e'
'3rd quarter': (topic) -> assert.equal topic(0.75), '#a6cfc1'
.export(module)
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