Class: Rubygame::Color::ColorHSV

Inherits:
Object
  • Object
show all
Includes:
ColorBase
Defined in:
lib/rubygame/color/models/hsv.rb

Overview

Represents color in the HSV (Hue, Saturation, Value) color space.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ColorBase

#*, #+, #-, #/, #average, #over

Constructor Details

#initialize(color) ⇒ ColorHSV

call-seq:

new( [h,s,v,a] )  ->  ColorHSV
new( [h,s,v] )  ->  ColorHSV
new( color )  ->  ColorHSV

Create a new instance from an Array or an existing color (of any type). If the alpha (opacity) component is omitted from the array, full opacity will be used.

All color components range from 0.0 to 1.0.



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# File 'lib/rubygame/color/models/hsv.rb', line 42

def initialize( color )
  if color.kind_of?(Array)
    @h, @s, @v, @a = color.collect { |i| i.to_f }
    @a = 1.0 unless @a
  elsif color.respond_to?(:to_rgba_ary)
    @h, @s, @v, @a = self.class.rgba_to_hsva( *color.to_rgba_ary )
  end
end

Instance Attribute Details

#a ⇒ Object (readonly)

Returns the value of attribute a.



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# File 'lib/rubygame/color/models/hsv.rb', line 29

def a
  @a
end

#h ⇒ Object (readonly)

Returns the value of attribute h.



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# File 'lib/rubygame/color/models/hsv.rb', line 29

def h
  @h
end

#s ⇒ Object (readonly)

Returns the value of attribute s.



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# File 'lib/rubygame/color/models/hsv.rb', line 29

def s
  @s
end

#v ⇒ Object (readonly)

Returns the value of attribute v.



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# File 'lib/rubygame/color/models/hsv.rb', line 29

def v
  @v
end

Class Method Details

.hsva_to_rgba(h, s, v, a) ⇒ Object

Convert the hue, saturation, value, and alpha to the equivalent red, green, blue, and alpha.



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# File 'lib/rubygame/color/models/hsv.rb', line 110

def hsva_to_rgba( h, s, v, a ) # :nodoc:
  # Determine what part of the "color hexagon" the hue is in.
  hi = (h * 6).floor % 6

  # Fractional part
  f  = (h * 6) - hi

  # Helper values
  p  = v * (1.0 - s)
  q  = v * (1.0 - (f * s))
  t  = v * (1.0 - ((1.0 - f) * s))

  # Finally calculate the rgb values
  r, g, b = calculate_rgb(hi, v, p, t, q)

  return [r, g, b, a]
end

.new_from_rgba(rgba) ⇒ Object 



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# File 'lib/rubygame/color/models/hsv.rb', line 64

def new_from_rgba( rgba )
  new( rgba_to_hsva(*rgba) )
end

.new_from_sdl_rgba(rgba) ⇒ Object 



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# File 'lib/rubygame/color/models/hsv.rb', line 68

def new_from_sdl_rgba( rgba )
  new_from_rgba( rgba.collect { |i| i / 255.0 } )
end

.rgba_to_hsva(r, g, b, a) ⇒ Object

Convert the red, green, blue, and alpha to the equivalent hue, saturation, value, and alpha.



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# File 'lib/rubygame/color/models/hsv.rb', line 74

def rgba_to_hsva( r, g, b, a ) # :nodoc:
  rgb_arr = [r, g, b]
  max     = rgb_arr.max
  min     = rgb_arr.min

  # Calculate hue.
  if min == max 
    h = 0 
    # Undefined in this case, but set it to zero
  elsif max == r and g >= b
    h = (1.quo(6) * (g - b) / (max - min)) + 0
  elsif max == r and g < b
    h = (1.quo(6) * (g - b) / (max - min)) + 1.0
  elsif max == g
    h = (1.quo(6) * (b - r) / (max - min)) + 1.quo(3)
  elsif max == b
    h = (1.quo(6) * (r - g) / (max - min)) + 2.quo(3)
  else 
    raise "Should never happen"
  end

  # Calulate value.
  v = max

  # Calculate saturation.
  if max == 0.0
    s = 0.0
  else
    s = 1.0 - (min / max)
  end  
  
  return [h,s,v,a]
end

Instance Method Details

#to_rgba_ary ⇒ Object

Return an Array with the red, green, blue, and alpha components of the color (converting the color to the RGBA model first).



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# File 'lib/rubygame/color/models/hsv.rb', line 53

def to_rgba_ary
  return self.class.hsva_to_rgba( @h, @s, @v, @a )
end

#to_s ⇒ Object Also known as: inspect 



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# File 'lib/rubygame/color/models/hsv.rb', line 57

def to_s
  "#<#{self.class} [#{@h}, #{@s}, #{@v}, #{@a}]>"
end