1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
|
###
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')
|
