Class: Tioga::Colormaps

Inherits:
Object
  • Object
show all
Defined in:
lib/Tioga/Colormaps.rb

Overview

These are the methods for creating and using colormaps and color spaces in PDF graphics.

Instance Method Summary collapse

Instance Method Details

#convert_to_colormap(reds, greens, blues) ⇒ Object

Returns a colormap corresponding to the given vectors of intensities. The intensities must be numbers between 0 and 1, and the vectors must be of equal lengths.



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# File 'lib/Tioga/Colormaps.rb', line 83

def convert_to_colormap(reds, greens, blues)
end

#create_colormap(dict) ⇒ Object

Returns a color map as specified by the dictionary argument dict. The ‘length’ parameter determines the number of entries in the map and must be an integer between 2 and 256. The ‘points’ vector gives positions between 0.0 and 1.0 where the colors are explicitly specified for the map. The first color map entry corresponds to position 0.0, the last map entry is for position 1.0, and intermediate map entries are spaced evenly in between. The color specifications are given either as RGB triples (in the vectors ‘Rs’, ‘Gs’, and ‘Bs’) or as HLS triples (in the vectors ‘Hs’, ‘Ls’, and ‘Ss’). In either case, there must be the same number of triples as there are positions in the ‘points’ vector. The color position points is assigned the color from the corresponding Rs, Gs, and Bs for the RGB case. In the HLS case, the triple Hs, Ls, and Ss is converted to a triple of RGB intensities, and that is assigned to the color position given by points. Color map entries for other positions are determined by linear interpolation from the neighboring assigned colors.

See also the prebuilt colormaps: intense_colormap, mellow_colormap, and rainbow_colormap.

Dictionary Entries

'length'   => an_integer      # integer between 2 and 256.  default is 256.
'points'   => a_dvector       # increasing locations starting at 0.0 and ending at 1.0
'Rs'       => a_dvector       # red intensities (between 0.0 and 1.0)
'Gs'       => a_dvector       # green intensities (between 0.0 and 1.0)
'Bs'       => a_dvector       # blue intensities (between 0.0 and 1.0)
'Hs'       => a_dvector       # hue angles in degrees (between 0 and 360)
'Ls'       => a_dvector       # lightness (between 0.0 and 1.0)
'Ss'       => a_dvector       # saturation (between 0.0 and 1.0)



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# File 'lib/Tioga/Colormaps.rb', line 34

def create_colormap(dict)
end

#create_gradient_colormap(dict) ⇒ Object

Returns a color map for a gradient of HLS colors as specified by the dictionary argument dict. The hue is either fixed (‘hue’) or varies linearly (from ‘starting_H’ to ‘ending_H’). The lightness is either fixed (‘lightness’) or varies linearly (from ‘starting_L’ to ‘ending_L’). The saturation is either fixed (‘saturation’) or varies linearly (from ‘starting_S’ to ‘ending_S’).

Dictionary Entries

'hue'             => a_float   # hue angle in degrees (default 0)
'starting_H'      => a_float   # the starting hue angle
'ending_H'        => a_float   # the ending hue angle
'lightness'       => a_float   # lightness (default 0.5)
'starting_L'      => a_float   # the starting lightness
'ending_L'        => a_float   # the ending lightness
'saturation'      => a_float   # saturation (default 0.5)
'starting_S'      => a_float   # the starting saturation
'ending_S'        => a_float   # the ending saturation



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# File 'lib/Tioga/Colormaps.rb', line 77

def create_gradient_colormap(dict)
end

#get_color_from_colormap(colormap, color_position) ⇒ Object

Returns the triple [ red, green, blue ] for the intensities of the color at the given color_position in colormap. Recall that a color position is a number between 0 and 1. See create_colormap.



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# File 'lib/Tioga/Colormaps.rb', line 89

def get_color_from_colormap(colormap, color_position)
end

#hls_to_rgb(hls_vec) ⇒ Object

Returns a vector of [ red, green, blue ] intensities corresponding to the hls_vec color given as [ hue, lightness, saturation ]. See also rgb_to_hls.



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# File 'lib/Tioga/Colormaps.rb', line 94

def hls_to_rgb(hls_vec)
end

#intense_colormap ⇒ Object

:call-seq:

intense_colormap

Returns a colormap with fully saturated reds and blues.



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# File 'lib/Tioga/Colormaps.rb', line 41

def intense_colormap
end

#mellow_colormap ⇒ Object

:call-seq:

mellow_colormap

Returns a colormap with reds and blues in which the saturation drops for high and low color positions,



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# File 'lib/Tioga/Colormaps.rb', line 48

def mellow_colormap 
end

#rainbow_colormap ⇒ Object

:call-seq:

rainbow_colormap

Returns a colormap covering the spectrum from red, orange, yellow, green, blue, indigo, to violet (special thanks to Roy G. Biv for providing this).



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# File 'lib/Tioga/Colormaps.rb', line 56

def rainbow_colormap
end

#rgb_to_hls(rgb_vec) ⇒ Object

Returns a vector of [ hue, lightness, saturation ] corresponding to the rgb_vec color given as [ red, green, blue ] intensities. See also hls_to_rgb.



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# File 'lib/Tioga/Colormaps.rb', line 99

def rgb_to_hls(rgb_vec)
end

#string_hls_to_rgb(str) ⇒ Object

Returns a new string of [ red, green, blue ] byte triples corresponding to the colors given in str as triples of [ hue, lightness, saturation ]. For representation as a byte, intensities in range 0.0 to 1.0 are multiplied by 255 and rounded; hue angles in the range 0.0 to 360.0 are divided by 360, multiplied by 255, and rounded. See also string_hls_to_rgb!.



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# File 'lib/Tioga/Colormaps.rb', line 108

def string_hls_to_rgb(str)
end

#string_hls_to_rgb!(str) ⇒ Object

Modifies in-place the string of [ red, green, blue ] byte triples to give the corresponding colors as triples of [ hue, lightness, saturation ].

See also string_hls_to_rgb.



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# File 'lib/Tioga/Colormaps.rb', line 114

def string_hls_to_rgb!(str)
end

#string_rgb_to_hls(str) ⇒ Object

Returns a new string of [ hue, lightness, saturation ] byte triples corresponding to the colors given in str as triples of [ red, green, blue ].

For representation as a byte, intensities in range 0.0 to 1.0 are multiplied by 255 and rounded; hue angles in the range 0.0 to 360.0 are divided by 360, multiplied by 255, and rounded. See also string_rgb_to_hls!.



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# File 'lib/Tioga/Colormaps.rb', line 122

def string_rgb_to_hls(str)
end

#string_rgb_to_hls!(str) ⇒ Object

Modifies in-place the string of [ hue, lightness, saturation ] byte triples to give the corresponding colors as triples of [ red, green, blue ].

See also string_rgb_to_hls.



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# File 'lib/Tioga/Colormaps.rb', line 128

def string_rgb_to_hls!(str)
end