Class Name: Colour Index

Superclass - <Colour>

Subclasses

Definition

An instance of this DRM class provides the means of referencing a <Primitive Colour> that is contained in a <Colour Table>.

A <Colour Index> instance contains an index into the primary <Colour Table> of the <Colour Table Group> to which it is associated. The <Colour Table Group> specifies which of its component <Colour Table> instances is being used, while the <Colour Index> specifies which <Primitive Colour> within that primary <Colour Table> is being referenced.

Primary Page in DRM Diagram:

• 14

Secondary Pages in DRM Diagram:

Example

1. Consider a <Colour Table Group>, the primary <Colour Table> of which consists of <Primitive Colour> instances for Out-the-Window (OTW) viewing conditions.

   A <Polygon> that references the kth <Primitive Colour> in this table will do so by having a <Colour Index> component that is associated to the <Colour Table Group> and the index value of which is set to k. If the <Colour Index> is solely responsible for the <Polygon>'s colour, its intensity_level will be 100.0.

FAQs

I am attempting to consume an object, e.g. a <Polygon>, the <Colour> of which is specified by a <Colour Index>. What can I do to get access to the actual <Primitive Colour> being referred to?

A consumer can access the actual <Primitive Colour> instances contained within a <Colour Table>, just as though <Inline Colour> instances had been used, via the Level 0 API. See SE_InitializeComponentIterator()'s directly_attach_table_components parameter, and SE_GetComponent()'s directly_attach_table_components parameter.

How can I, as a data provider, specify that a <Colour> contributes x percent (e.g. 25%) of the total effect on a coloured object, while an <Image Mapping Function> provides the remaining 100%-x (e.g. 75%)?

See <Colour Index>'s intensity_level field and <Image Mapping Function>'s intensity_level field.

Constraints

• <<Colour Mapping Restrictions>>

Associated to (one-way)

• one <Colour Table Group> instance

Composed of (two-way)(inherited)

• zero or one <Presentation Domain> instance (notes)
• zero or one <Translucency> instance

Composed of (two-way)

• zero or one <Colour Index Control Link> instance

Component of (two-way)(inherited)

• zero or one <Colour Entry Table> instance
• zero or more <Aggregate Feature> instances
• zero or more <Aggregate Geometry> instances
• zero or more <Attribute Set> instances
• zero or more <Base Vertex> instances
• zero or more <Colour Set> instances
• zero or more <Primitive Feature> instances
• zero or more <Primitive Geometry> instances

Inherited Field Elements

Field Elements

Notes

Composed of Notes

Presentation_Domain

 If present, this component identifies the type of sensor for which
 the given <Colour> instance is applicable.

Fields Notes

colour_mapping

 The set of SE_Colour_Mapping tokens applicable to the given
 <Colour> instance.

index

 This specifies which <Primitive Colour> within the referenced
 <Colour Table Group>'s primary <Colour Table> is being
 referred to.

intensity_level

 This value is between 0.0 and 1.0

 This value specifies the percent contribution of the <Colour> to
 the total effect on the coloured object(s). Multiply the <Colour Data>
 values within the referenced <Primitive Colour> by this value to
 obtain their contribution to the total colour of the affected
 coloured object(s).