--
-- File      :  Color.cdl
-- Created   :  Mon 11 Jan 1993
-- Author    : CKY / Contract Toubro-Larsen ( Niraj RANGWALA )
--
---Copyright : MATRA-DATAVISION  1993
--

class Color from IGESGraph  inherits ColorEntity

        ---Purpose : defines IGESColor, Type <314> Form <0>
        --           in package IGESGraph
        --
        --           The Color Definition Entity is used to communicate the
        --           relationship of primary colors to the intensity level of
        --           the respective graphics devices as a percent of full
        --           intensity range.

uses

            IGESEntity          from IGESData,
            HAsciiString from TCollection

is

        Create returns mutable Color;

        -- Specific Methods pertaining to class

        Init (me         : mutable;
              red        : Real;
              green      : Real;
              blue       : Real;
              aColorName : HAsciiString);
        ---Purpose : This method is used to set the fields of the class Color
        --       - red        : Red   color intensity (range 0.0 to 100.0)
        --       - green      : Green color intensity (range 0.0 to 100.0)
        --       - blue       : Blue  color intensity (range 0.0 to 100.0)
        --       - aColorName : Name of the color (optional)

        RGBIntensity (me; Red, Green, Blue : out Real);
        -- returns the RGB intensities in the Red, Green, Blue
        -- fields respectively

        CMYIntensity (me; Cyan, Magenta, Yellow : out Real);
        -- returns the CMY equivalents of RGB intensities.
        --
        -- The algorithm used for getting CMY from RGB is :
        --
        --          C = 100.0 - R       where : R = red     C = cyan
        --          G = 100.0 - M               G = green   M = magenta
        --          B = 100.0 - Y               B = blue    Y = yellow
        --

        HLSPercentage (me; Hue, Lightness, Saturation : out Real);
        -- returns the HLS equivalents of RGB intensities.
        --
        -- The algorithm used for getting HLS from RGB is :
        --
        --     H = (1/(2*PI))*ARCTAN((2*R - G - B) / (SQUAREROOT(3)*(G - B)))
        --     L = (1 / 3)*(R + G + B)
        --     S = SQUAREROOT(R*R + G*G + B*B - R*G - R*B - B*G)
        --
        -- where    H = Hue, L = Lightness, S = Saturation,
        --          PI = 3.14... (constant)
        --

        HasColorName (me) returns Boolean;
        ---Purpose : returns True if optional character string is assigned,
        --         False otherwise.

        ColorName (me) returns HAsciiString from TCollection;
        ---Purpose : if HasColorName() is True  returns the Verbal description of
        -- the Color.

fields

--
-- Class    : IGESGraph_Color
--
-- Purpose  : Declaration of the variables specific to Color
--
-- Reminder : A Color is defined by :
--              - Red   color intensity
--              - Green color intensity
--              - Blue  color intensity
--              - Optional name of the color
--

        theRed       : Real;

        theGreen     : Real;

        theBlue      : Real;

        theColorName : HAsciiString;

end Color;