Gray¶

Status: Experimental

present and registered, but lightly documented and not yet covered by dedicated tests.

Description¶

Gray

The named colour GrayLevel[0.5].

Examples (3)¶

Every input below was run against the current Mathilda build and its output recorded.

Applications (3)¶

A named colour evaluates to its colour directive

In[1]:= Gray
Out[1]= GrayLevel[0.5]

Same thing, confirmed

In[2]:= Gray === GrayLevel[0.5]
Out[2]= True

Its components

In[3]:= List @@ Gray
Out[3]= {0.5}

Implementation notes¶

Definition. Gray is one of Mathilda's named colour constants — a medium gray. Like Mathematica's own named colours it is not an inert head but a symbol whose OwnValue is a GrayLevel literal, so it resolves to a real colour directive anywhere one is expected: Gray evaluates to GrayLevel[0.5].

Representation. register_color("Gray", ...) in src/graphics/graphics_init.c installs the OwnValue Gray -> GrayLevel[0.5] and marks the symbol Protected; the component builder prints an exact 0 or 1 as a plain integer and anything else as a real, matching Mathematica's own InputForm. The docstring lives centrally in src/info.c. Because it is an OwnValue (not an inert head), a non-held graphics argument or an evaluated-once plot option sees the expanded GrayLevel[0.5], exactly as a literal colour would.

Usage & limits. Protected. It is a value, not a function: feeding it a wrong "argument" is meaningless. Use it as a PlotStyle / VectorStyle directive, inside Graphics primitives, or in ColorRules. The grey-scale constants (Black, White, Gray, LightGray) expand to GrayLevel; the rest to RGBColor.

Attributes: Protected.

References¶

Source: src/graphics/graphics_init.c
Specification index: Mathilda_spec.md

Notes & additional examples¶

Notes¶

Gray is one of Mathilda's named colour constants. Rather than being an inert head, it is a symbol whose OwnValue is the directive GrayLevel[0.5], so it resolves to a real colour wherever one is expected — as a PlotStyle / VectorStyle directive, inside Graphics primitives, or in ColorRules.

A grey-scale constant, so it expands to a GrayLevel directive rather than RGBColor. The exact components 0 and 1 print as plain integers (matching Mathematica's InputForm). Gray is Protected.