Module java.desktop

Class ICC_ProfileRGB

java.lang.Object
java.awt.color.ICC_Profile
java.awt.color.ICC_ProfileRGB
All Implemented Interfaces:
Serializable

public class ICC_ProfileRGB
extends ICC_Profile
The ICC_ProfileRGB class is a subclass of the ICC_Profile class that represents profiles which meet the following criteria: the profile's color space type is RGB, and the profile includes the redColorantTag, greenColorantTag, blueColorantTag, redTRCTag, greenTRCTag, blueTRCTag, mediaWhitePointTag tags. The getInstance methods in the ICC_Profile class will return an ICC_ProfileRGB object when the above conditions are met. Three-component, matrix-based input profiles and RGB display profiles are examples of this type of profile.

The advantage of this class is that it provides color transform matrices and lookup tables that Java or native methods can use directly to optimize color conversion in some cases.

To transform from a device profile color space to the CIEXYZ Profile Connection Space, each device color component is first linearized by a lookup through the corresponding tone reproduction curve (TRC). The resulting linear RGB components are converted to the CIEXYZ PCS using a a 3x3 matrix constructed from the RGB colorants.


                 linearR = redTRC[deviceR]

                 linearG = greenTRC[deviceG]

                 linearB = blueTRC[deviceB]

   _      _       _                                             _   _         _
  [  PCSX  ]     [  redColorantX  greenColorantX  blueColorantX  ] [  linearR  ]
  [        ]     [                                               ] [           ]
  [  PCSY  ]  =  [  redColorantY  greenColorantY  blueColorantY  ] [  linearG  ]
  [        ]     [                                               ] [           ]
  [_ PCSZ _]     [_ redColorantZ  greenColorantZ  blueColorantZ _] [_ linearB _]

 
The inverse transform is performed by converting PCS XYZ components to linear RGB components through the inverse of the above 3x3 matrix, and then converting linear RGB to device RGB through inverses of the TRCs.

See Also:
Serialized Form
  • Field Details

    • REDCOMPONENT

      public static final int REDCOMPONENT
      Used to get a gamma value or TRC for the red component.
      See Also:
      Constant Field Values
    • GREENCOMPONENT

      public static final int GREENCOMPONENT
      Used to get a gamma value or TRC for the green component.
      See Also:
      Constant Field Values
    • BLUECOMPONENT

      public static final int BLUECOMPONENT
      Used to get a gamma value or TRC for the blue component.
      See Also:
      Constant Field Values
  • Method Details

    • getMediaWhitePoint

      public float[] getMediaWhitePoint()
      Returns an array that contains the components of the profile's mediaWhitePointTag.
      Returns:
      a 3-element float array containing the x, y, and z components of the profile's mediaWhitePointTag
    • getMatrix

      public float[][] getMatrix()
      Returns a 3x3 float matrix constructed from the X, Y, and Z components of the profile's redColorantTag, greenColorantTag, and blueColorantTag.

      This matrix can be used for color transforms in the forward direction of the profile--from the profile color space to the CIEXYZ PCS.

      Returns:
      a 3x3 float array that contains the x, y, and z components of the profile's redColorantTag, greenColorantTag, and blueColorantTag
    • getGamma

      public float getGamma​(int component)
      Returns a gamma value representing the tone reproduction curve (TRC) for a particular component. The component parameter must be one of REDCOMPONENT, GREENCOMPONENT, or BLUECOMPONENT.

      If the profile represents the TRC for the corresponding component as a table rather than a single gamma value, an exception is thrown. In this case the actual table can be obtained through the getTRC(int) method. When using a gamma value, the linear component (R, G, or B) is computed as follows:

      
                                                 gamma
                linearComponent = deviceComponent
      
       

      Parameters:
      component - the ICC_ProfileRGB constant that represents the component whose TRC you want to retrieve
      Returns:
      the gamma value as a float
      Throws:
      ProfileDataException - if the profile does not specify the corresponding TRC as a single gamma value
    • getTRC

      public short[] getTRC​(int component)
      Returns the TRC for a particular component as an array. Component must be REDCOMPONENT, GREENCOMPONENT, or BLUECOMPONENT. Otherwise the returned array represents a lookup table where the input component value is conceptually in the range [0.0, 1.0]. Value 0.0 maps to array index 0 and value 1.0 maps to array index length-1. Interpolation might be used to generate output values for input values that do not map exactly to an index in the array. Output values also map linearly to the range [0.0, 1.0]. Value 0.0 is represented by an array value of 0x0000 and value 1.0 by 0xFFFF. In other words, the values are really unsigned short values even though they are returned in a short array.

      If the profile has specified the corresponding TRC as linear (gamma = 1.0) or as a simple gamma value, this method throws an exception. In this case, the getGamma(int) method should be used to get the gamma value.

      Parameters:
      component - the ICC_ProfileRGB constant that represents the component whose TRC you want to retrieve: REDCOMPONENT, GREENCOMPONENT, or BLUECOMPONENT
      Returns:
      a short array representing the TRC
      Throws:
      ProfileDataException - if the profile does not specify the corresponding TRC as a table