def change_color(color, kwargs)
assert_type color, :Color, :color
with = Sass::Util.map_hash(
'red' => ['Red value', 0..255],
'green' => ['Green value', 0..255],
'blue' => ['Blue value', 0..255],
'hue' => [],
'saturation' => ['Saturation', 0..100, '%'],
'lightness' => ['Lightness', 0..100, '%'],
'alpha' => ['Alpha channel', 0..1]
) do |name, (desc, range, unit)|
val = kwargs.delete(name)
next unless val
assert_type val, :Number, name
if range
val = Sass::Util.check_range(desc, range, val, unit)
else
val = val.value
end
[name.to_sym, val]
end
unless kwargs.empty?
name, val = kwargs.to_a.first
raise ArgumentError.new("Unknown argument $#{name} (#{val})")
end
color.with(with)
end