Class: Dvl::Color::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/dvl/color/generator.rb

Constant Summary collapse

DARK_BACKGROUND_CUTOFF =
120

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(background_color) ⇒ Generator

Returns a new instance of Generator.

Parameters:

  • background_color (Chroma::Color or String)


12
13
14
15
16
17
18
19
20
21
# File 'lib/dvl/color/generator.rb', line 12

def initialize(background_color)
  self.background_color = background_color

  unless background_color.is_a?(Chroma::Color)
    self.background_color = Chroma.paint(background_color)
  end

  self.input_background, self.input_background_focus, self.input_color = generate_input_colors
  self.dropdown_background, self.dropdown_color = generate_dropdown_colors
end

Instance Attribute Details

#background_colorObject

Returns the value of attribute background_color.



4
5
6
# File 'lib/dvl/color/generator.rb', line 4

def background_color
  @background_color
end

Returns the value of attribute dropdown_background.



4
5
6
# File 'lib/dvl/color/generator.rb', line 4

def dropdown_background
  @dropdown_background
end

Returns the value of attribute dropdown_color.



4
5
6
# File 'lib/dvl/color/generator.rb', line 4

def dropdown_color
  @dropdown_color
end

#input_backgroundObject

Returns the value of attribute input_background.



4
5
6
# File 'lib/dvl/color/generator.rb', line 4

def input_background
  @input_background
end

#input_background_focusObject

Returns the value of attribute input_background_focus.



4
5
6
# File 'lib/dvl/color/generator.rb', line 4

def input_background_focus
  @input_background_focus
end

#input_colorObject

Returns the value of attribute input_color.



4
5
6
# File 'lib/dvl/color/generator.rb', line 4

def input_color
  @input_color
end

Instance Method Details

#base_colorObject



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
# File 'lib/dvl/color/generator.rb', line 84

def base_color
  @base_color ||= begin
    text = background_color.dup

    # If the background is dark, we lighten it.
    # If the background is light, we darken it.
    amt = if background_color.brightness < DARK_BACKGROUND_CUTOFF # Dark
            1
          else
            -1
          end

    target = target_contrast_ratio

    while contrast(background_color, text) < target
      new_text = text.lighten(amt)

      # prevent infinite loop
      break if text == new_text

      text = new_text
    end

    # If the background is a conservative color, use a conservative
    # (desaturated) text color.

    if conservative_background_dark? || conservative_background_light?
      hsl = text.hsl
      hsl.s = hsl.s * 0.15
      text = Chroma.paint(hsl)
    end

    text
  end
end

#blackObject



195
196
197
# File 'lib/dvl/color/generator.rb', line 195

def black
  Chroma.paint('#000')
end

#conservative_background_dark?Boolean

Returns:

  • (Boolean)


66
67
68
# File 'lib/dvl/color/generator.rb', line 66

def conservative_background_dark?
  background_color.brightness < 52
end

#conservative_background_light?Boolean

Returns:

  • (Boolean)


70
71
72
# File 'lib/dvl/color/generator.rb', line 70

def conservative_background_light?
  background_color.brightness > 229
end

#error_bubble_backgroundObject



171
172
173
174
175
176
177
# File 'lib/dvl/color/generator.rb', line 171

def error_bubble_background
  if error_color.brightness > 200
    white
  else
    error_color
  end
end

#error_bubble_colorObject



179
180
181
182
183
184
185
# File 'lib/dvl/color/generator.rb', line 179

def error_bubble_color
  if error_bubble_background == white
    background_color
  else
    white
  end
end

#error_colorObject



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
# File 'lib/dvl/color/generator.rb', line 120

def error_color
  @error_color ||= begin
    error = background_color.dup

    # Spin the color wheel until we land on "red"
    amt = if error.hsl.h > 180
            15
          else
            -15
          end

    while !red?(error)
      error = error.spin(amt)
    end

    # White
    if background_color == white
      error = Chroma.paint('d95b76')
    # Black
    elsif background_color == black
      error = Chroma.paint('d95b76')
    # Grayscale
    elsif error.hsl.s == 0
      error = error.saturate(100)
    # Otherwise, ensure saturation is at least 0.4, or else it's not really red...
    elsif error.hsl.s < 0.4
      hsl = error.hsl
      hsl.s = 0.4
      error = Chroma.paint(hsl)
    elsif conservative_background_light?
      hsl = error.hsl
      hsl.l = hsl.l - 0.4
      error = Chroma.paint(hsl)
    end

    amt = if background_color.brightness < 100
            2
          else
            -2
          end

    while contrast(error, background_color) < 2.5
      new_error = error.lighten(amt)
      break if error == new_error
      error = new_error
    end

    error
  end
end

#generate_dropdown_colorsObject



187
188
189
190
191
192
193
# File 'lib/dvl/color/generator.rb', line 187

def generate_dropdown_colors
  if background_color.brightness < DARK_BACKGROUND_CUTOFF
    [base_color, background_color]
  else
    [background_color, base_color]
  end
end

#target_contrast_ratioObject



74
75
76
77
78
79
80
81
82
# File 'lib/dvl/color/generator.rb', line 74

def target_contrast_ratio
  if conservative_background_dark?
    13
  elsif conservative_background_light?
    10
  else
    7
  end
end

#to_debug_sObject



46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
# File 'lib/dvl/color/generator.rb', line 46

def to_debug_s
  str = []

  to_h.each do |k, v|
    str << "#{k}: #{v}"
  end

  str << "Background brightness: #{background_color.brightness}"

  str << "Ratio: #{contrast(background_color, base_color).round(2)}"
  str << "Error Ratio: #{contrast(background_color, error_color).round(2)}"
  str << "Error Bubble Ratio: #{contrast(error_bubble_background, error_bubble_color).round(2)}"
  str << "Input ratio: #{contrast(input_background, input_color).round(2)}"
  str << "Error satur: #{error_color.hsl.s.round(2)}"
  str << "Conservative light: #{conservative_background_light?}"
  str << "Conservative dark: #{conservative_background_dark?}"

  str.join("<br>")
end

#to_hObject



23
24
25
26
27
28
29
30
31
32
33
34
35
36
# File 'lib/dvl/color/generator.rb', line 23

def to_h
  {
    backgroundColor: background_color.to_hex,
    baseColor: base_color.to_hex,
    errorColor: error_color.to_hex,
    errorBubbleBackground: error_bubble_background.to_hex,
    errorBubbleColor: error_bubble_color.to_hex,
    inputBackground: input_background.to_hex,
    inputBackgroundFocus: input_background_focus.to_hex,
    inputColor: input_color.to_hex,
    dropdownBackground: dropdown_background.to_hex,
    dropdownColor: dropdown_color.to_hex
  }
end

#to_scssObject



38
39
40
41
42
43
44
# File 'lib/dvl/color/generator.rb', line 38

def to_scss
  ''.tap do |str|
    to_h.each do |k, v|
      str << "$#{k}:#{v};"
    end
  end
end

#whiteObject



199
200
201
# File 'lib/dvl/color/generator.rb', line 199

def white
  Chroma.paint('#fff')
end