Abstract Class Name: Colour

Superclass - <SEDRIS Abstract Base>

Subclasses

• <Colour Index>
• <Inline Colour>

Definition

An instance of this DRM class specifies the colour data for a DRM object.

Primary Page in DRM Diagram:

• 14

Secondary Pages in DRM Diagram:

• 4
• 5
• 8
• 18
• 19
• 23

Example

See concrete subclasses for examples.

FAQs

Where can one find more information on colour in the DRM?

See P4V8 of the SEDRIS Documentation Set for further information.

Where do RGB values go in all this? How is a single, simple colour represented?

The actual colour values are represented by a single <Primitive Colour> instance for each <Colour> instance. The location of this <Primitive Colour> instance depends on whether the <Colour> instance in question is an <Inline Colour> instance or a <Colour Index> instance. See those classes for details.

A single, simple colour is represented as an <Inline Colour> instance, the colour_mapping of which is set to some variation of PRIMARY_COLOUR, and the <Primitive Colour> instance of which has only an <Ambient Colour> component specified.

See <Primitive Colour> for further discussion.

How can a data provider represent a colour (such as RGB) that has a coefficient (such as K)?

The data provider in this example has two options.

1. The coefficient can be factored into the colour to create an <Inline Colour> instance.

2. The colour can be placed in a <Colour Table> instance, then referenced by a <Colour Index> instance, the intensity_level of which is set to the value of the coefficient.

How does one determine how to apply a <Colour> instance to the DRM object using it? What is the purpose of the colour_mapping field?

The colour_mapping field indicates how to apply a <Colour> instance to the DRM object using it -- which side of the DRM object it applies to, whether it is used for the primary colour, for distance or image blending, or something else. (See SE_Colour_Mapping for the details of specific colour mappings).

Incidentally, the colour_mapping field is a set, rather than a simple enumeration, in order to simplify the consumption task of identifying what a colour applies to. Its members are taken from the SE_Colour_Mapping enumeration.

Is a <Primitive Geometry> instance required to have a PRIMARY_COLOUR as a component (whether direct or inherited)?

No. Some texture mapping techniques do not require colour to be present on <Polygon> instances, so some data providers have no PRIMARY_COLOUR to supply. If a consumer cannot handle the texture mapping technique used in a transmittal, the consumer will have to choose some appropriate default colour.

Are all combinations of PRIMARY_COLOUR, DISTANCE_BLEND_COLOUR, and IMAGE_BLEND_COLOUR colour mapping valid for the OTW front face of a single polygon?

Yes.

Constraints

• <<Publishable Object>>
• <<Colour Mapping Constraints>>
• <<Presentation Domain Constraints>>

Composed of (two-way)

• zero or one <Presentation Domain> instance¹
• zero or one <Translucency> instance

Component of (two-way)

• zero or more <Aggregate Feature> instances
• zero or more <Aggregate Geometry> instances
• zero or more <Primitive Feature> instances
• zero or more <Primitive Geometry> instances
• zero or more <Property Set> instances
• zero or more <Vertex> instances

Inherited Field Elements

Field Elements

Notes

Composed of Notes

Presentation_Domain

Fields Notes

colour_mapping

The colour_mapping field specifies the set of SE_Colour_Mapping members applicable to the <Colour> instance.