The SEDRIS Data Representation Model
APPENDIX A - Classes Colour Table |
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An instance T of this DRM class specifies an ordered collection of <Primitive Colour> instances such that, for the <Colour Table Group> instance G of which T is itself a component, the index field of any <Colour Index> instance associated to G unambiguously specifies one of the <Primitive Colour> components of T.
Consider a data provider whose format specifies colours using palettes. To convey exactly the colour information used, each palette is represented as the primary <Colour Table> component of a <Colour Table Group> instance.
A <Colour Table> instance does not contain <Inline Colour> components, because a <Colour Table> exists to store "just the colour", without any additional <Translucency>.
The interpretation of a <Colour Index> is clearer if the referenced <Colour Table> entry cannot have additional <Translucency>.
Storing <Primitive Colour> instances in a <Colour Table> allows greater re-use, since the same <Primitive Colour> can be referenced by different <Colour Index> instances with different <Translucency> components.
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