chroma-js

### chroma.js Copyright (c) 2011-2013, Gregor Aisch All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * The name Gregor Aisch may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GREGOR AISCH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. @source: https://github.com/gka/chroma.js ### # minimal multi-purpose interface chroma.scale = (colors, positions) -> # constructor _mode = 'rgb' _nacol = chroma '#ccc' _spread = 0 _fixed = false _domain = [0, 1] _colors = [] _out = false _pos = [] _min = 0 _max = 1 _correctLightness = false _numClasses = 0 _colorCache = {} # private methods setColors = (colors, positions) -> if not colors? colors = ['#ddd', '#222'] if colors? and type(colors) == 'string' and chroma.brewer?[colors]? colors = chroma.brewer[colors] if type(colors) == 'array' # make a copy of the colors colors = colors.slice(0) # convert to chroma classes for c in [0..colors.length-1] col = colors[c] colors[c] = chroma(col) if type(col) == "string" # auto-fill color position if positions? _pos = positions else _pos = [] for c in [0..colors.length-1] _pos.push c/(colors.length-1) resetCache() _colors = colors setDomain = (domain = []) -> ### # use this if you want to display a limited number of data classes # possible methods are "equalinterval", "quantiles", "custom" ### _domain = domain _min = domain[0] _max = domain[domain.length-1] resetCache() if domain.length == 2 _numClasses = 0 else _numClasses = domain.length-1 getClass = (value) -> if _domain? n = _domain.length-1 i = 0 while i < n and value >= _domain[i] i++ return i-1 return 0 tmap = (t) -> t classifyValue = (value) -> val = value if _domain.length > 2 n = _domain.length-1 i = getClass(value) minc = _domain[0] + (_domain[1]-_domain[0]) * (0 + _spread * 0.5) # center of 1st class maxc = _domain[n-1] + (_domain[n]-_domain[n-1]) * (1 - _spread * 0.5) # center of last class val = _min + ((_domain[i] + (_domain[i+1] - _domain[i]) * 0.5 - minc) / (maxc-minc)) * (_max - _min) val getColor = (val, bypassMap=false) -> if isNaN(val) then return _nacol if not bypassMap if _domain.length > 2 c = getClass val t = c / (_numClasses-1) else t = f0 = if _min != _max then (val - _min) / (_max - _min) else 0 t = f0 = (val - _min) / (_max - _min) t = Math.min(1, Math.max(0, t)) else t = val if not bypassMap t = tmap t # lightness correction k = Math.floor(t * 10000) if _colorCache[k] col = _colorCache[k] else if type(_colors) == 'array' for i in [0.._pos.length-1] p = _pos[i] if t <= p col = _colors[i] break if t >= p and i == _pos.length-1 col = _colors[i] break if t > p and t < _pos[i+1] t = (t-p)/(_pos[i+1]-p) col = chroma.interpolate _colors[i], _colors[i+1], t, _mode break else if type(_colors) == 'function' col = _colors t _colorCache[k] = col col resetCache = () -> _colorCache = {} setColors colors, positions # public interface f = (v) -> c = getColor v if _out and c[_out] then c[_out]() else c f.domain = (domain, classes, mode='e', key) -> if not arguments.length return _domain if classes? d = chroma.analyze domain, key if classes == 0 domain = [d.min, d.max] else domain = chroma.limits d, mode, classes setDomain domain f f.mode = (_m) -> if not arguments.length return _mode _mode = _m resetCache() f f.range = (colors, _pos) -> setColors colors, _pos f f.out = (_o) -> _out = _o f f.spread = (val) -> if not arguments.length return _spread _spread = val f f.correctLightness = (v) -> if not arguments.length return _correctLightness _correctLightness = v resetCache() if _correctLightness tmap = (t) -> L0 = getColor(0, true).lab()[0] L1 = getColor(1, true).lab()[0] pol = L0 > L1 L_actual = getColor(t, true).lab()[0] L_ideal = L0 + (L1 - L0) * t L_diff = L_actual - L_ideal t0 = 0 t1 = 1 max_iter = 20 while Math.abs(L_diff) > 1e-2 and max_iter-- > 0 do () -> L_diff *= -1 if pol if L_diff < 0 t0 = t t += (t1 - t) * 0.5 else t1 = t t += (t0 - t) * 0.5 L_actual = getColor(t, true).lab()[0] L_diff = L_actual - L_ideal t else tmap = (t) -> t f f.colors = (out='hex') -> # returns all colors based on the defined classes colors = [] samples = [] if _domain.length > 2 for i in [1..._domain.length] samples.push (_domain[i-1]+_domain[i])*0.5 else samples = _domain for i in samples colors.push f(i)[out]() colors f # some pre-defined color scales: chroma.scales ?= {} chroma.scales.cool = -> chroma.scale [chroma.hsl(180,1,.9), chroma.hsl(250,.7,.4)] chroma.scales.hot = -> chroma.scale(['#000','#f00','#ff0','#fff'], [0,.25,.75,1]).mode('rgb')