Module cache_key

Hashing and other caching utilities for Color types.

In this crate, colors are implemented using f32. This means that color types aren’t Hash and Eq for good reasons:

• Equality on these types is not reflexive (consider NaN).
• Certain values have two representations (-0 and +0 are both zero).

However, it is still useful to create caches which key off these values. These are caches which don’t have any semantic meaning, but instead are used to avoid redundant calculations or storage.

Color supports creating these caches by using CacheKey<T> as the key in your cache. T is the key type (i.e. a color) which you want to use as the key. This T must implement both BitHash and BitEq, which are versions of the standard Hash and Eq traits which support implementations for floating point numbers which might be unexpected outside of a caching context.

Structs

CacheKey

A key usable in a hashmap to compare the bit representation types containing colors.

Traits

BitEq

An equivalence relation for types which normally wouldn’t have one, implemented using a bitwise comparison for floating point values.

BitHash

A hash implementation for types which normally wouldn’t have one, implemented using a hash of the bitwise equivalent types when needed.