Enum FoundPattern 

pub enum FoundPattern {
    Loaded(Arc<Pattern>),
    Unusable,
    Missing,
}

What scn found when it named a pattern.

The two halves are separate because finding the resource and loading the pattern fail differently. Finding it checks only that the resource exists and is a dictionary or a stream; that is what decides whether scn installs a pattern colour at all. Whether the pattern is usable — a /PatternType it recognises, a shading it can validate, steps it can tile with — is answered later, at draw time, and a failure there means the object paints nothing.

Collapsing the two makes an scn naming an unusable pattern a no-op, so the object keeps whatever colour was current and paints solid. On a page-sized rectangle over the default black that is an entirely black page, which is what four of the corpus’s fuzz files produced.

Variants

Loaded(Arc<Pattern>)

The resource exists and the pattern loaded.

Unusable

The resource exists but the pattern is unusable: a pattern colour is still installed, and it paints nothing.

Missing

No such resource, or it is neither a dictionary nor a stream. scn is a no-op and the previous colour stands.

Trait Implementations

impl Clone for FoundPattern

fn clone(&self) -> FoundPattern

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FoundPattern

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.