-
Notifications
You must be signed in to change notification settings - Fork 2
/
Copy pathHSLA.js
173 lines (144 loc) · 2.65 KB
/
HSLA.js
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
/**
* Module dependencies.
*/
var RGBA = require('./RGBA');
/**
* Expose `HSLA`.
*/
exports = module.exports = HSLA;
/**
* Initialize a new `HSLA` with the given h,s,l,a component values.
*
* @param {Number} h
* @param {Number} s
* @param {Number} l
* @param {Number} a
* @api public
*/
function HSLA(h,s,l,a){
if (!(this instanceof HSLA)) return new HSLA(h,s,l,a);
this.h = clampDegrees(h);
this.s = clampPercentage(s);
this.l = clampPercentage(l);
this.a = clampAlpha(a);
this.hsla = this;
}
/**
* Convert to HSLA (return self).
*
* @return {HSLA}
* @api public
*/
HSLA.prototype.toHSLA = function(){
return this;
};
/**
* Convert to RGBA.
*
* @return {RGBA}
* @api public
*/
HSLA.prototype.toRGBA = function(){
return RGBA.fromHSLA(this);
};
/**
* Return hsla(n,n,n,n).
*
* @return {String}
* @api public
*/
HSLA.prototype.toString = function(){
return 'hsla('
+ this.h + ','
+ this.s.toFixed(0) + ','
+ this.l.toFixed(0) + ','
+ this.a + ')';
};
/**
* Return `HSLA` representation of the given `color`.
*
* @param {RGBA} color
* @return {HSLA}
* @api public
*/
exports.fromRGBA = function(rgba){
var r = rgba.r / 255
, g = rgba.g / 255
, b = rgba.b / 255
, a = rgba.a;
var min = Math.min(r,g,b)
, max = Math.max(r,g,b)
, l = (max + min) / 2
, d = max - min
, h, s;
switch (max) {
case min: h = 0; break;
case r: h = 60 * (g-b) / d; break;
case g: h = 60 * (b-r) / d + 120; break;
case b: h = 60 * (r-g) / d + 240; break;
}
if (max == min) {
s = 0;
} else if (l < .5) {
s = d / (2 * l);
} else {
s = d / (2 - 2 * l);
}
h %= 360;
s *= 100;
l *= 100;
return new HSLA(h,s,l,a);
};
/**
* Adjust lightness by `percent`.
*
* @param {Number} percent
* @return {HSLA}
* @api public
*/
HSLA.prototype.adjustLightness = function(percent){
this.l = clampPercentage(this.l + this.l * (percent / 100));
return this;
};
/**
* Adjust hue by `deg`.
*
* @param {Number} deg
* @return {HSLA}
* @api public
*/
HSLA.prototype.adjustHue = function(deg){
this.h = clampDegrees(this.h + deg);
return this;
};
/**
* Clamp degree `n` >= 0 and <= 360.
*
* @param {Number} n
* @return {Number}
* @api private
*/
function clampDegrees(n) {
n = n % 360;
return n >= 0 ? n : 360 + n;
}
/**
* Clamp percentage `n` >= 0 and <= 100.
*
* @param {Number} n
* @return {Number}
* @api private
*/
function clampPercentage(n) {
return Math.max(0, Math.min(n, 100));
}
/**
* Clamp alpha `n` >= 0 and <= 1.
*
* @param {Number} n
* @return {Number}
* @api private
*/
function clampAlpha(n) {
return Math.max(0, Math.min(n, 1));
}