Struct ArtifactMetadata 

#[non_exhaustive]
pub struct ArtifactMetadata {
    pub width: Option<u32>,
    pub height: Option<u32>,
    pub frame_count: u32,
    pub duration: Option<Duration>,
    pub has_alpha: Option<bool>,
    pub orientation: Option<u16>,
}

Metadata that the Core layer can carry between decode and encode steps.

Examples

use truss::{ArtifactMetadata, Dimensions};

// The struct is `#[non_exhaustive]`, so start from `default()` and assign; a field
// truss adds later is then a minor change rather than a breaking one.
let mut meta = ArtifactMetadata::default();
meta.width = Some(1920);
meta.height = Some(1080);
assert_eq!(meta.dimensions(), Some(Dimensions::new(1920, 1080)));
assert_eq!(meta.frame_count, 1);

// With no orientation tag, the oriented dimensions are the stored ones.
assert_eq!(meta.oriented_dimensions(), Some(Dimensions::new(1920, 1080)));

// Orientation 6 is a quarter turn, so a transform swaps the axes.
let mut rotated = meta.clone();
rotated.orientation = Some(6);
assert_eq!(rotated.oriented_dimensions(), Some(Dimensions::new(1080, 1920)));

// When either dimension is unknown, dimensions() returns None
let mut partial = ArtifactMetadata::default();
partial.width = Some(100);
assert!(partial.dimensions().is_none());

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

width: Option<u32>

The rendered width in pixels, when known.

height: Option<u32>

The rendered height in pixels, when known.

frame_count: u32

The number of frames contained in the artifact.

duration: Option<Duration>

The total animation duration, when known.

has_alpha: Option<bool>

Whether the artifact contains alpha, when known.

orientation: Option<u16>

The EXIF orientation tag, when the artifact carries one.

width and height are the dimensions as stored in the container. A transform applies this tag by default, and values 5 to 8 transpose the two, so a caller that records dimensions at upload time and serves derivatives later needs this to know which way round the result will be. ArtifactMetadata::oriented_dimensions does that arithmetic.

Implementations

impl ArtifactMetadata

pub fn dimensions(&self) -> Option<Dimensions>

Returns the dimensions as a Dimensions value, if both width and height are known.

pub fn oriented_dimensions(&self) -> Option<Dimensions>

Returns the dimensions after the EXIF orientation is applied.

These are the dimensions a transform produces with auto-orientation on, which is the default. They equal ArtifactMetadata::dimensions whenever there is no orientation tag or the tag does not transpose the axes, so a caller can read these unconditionally.

Trait Implementations

impl Clone for ArtifactMetadata

fn clone(&self) -> ArtifactMetadata

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ArtifactMetadata

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

Formats the value using the given formatter.

impl Default for ArtifactMetadata

fn default() -> Self

Returns the “default value” for a type.

impl Eq for ArtifactMetadata

impl PartialEq for ArtifactMetadata

fn eq(&self, other: &ArtifactMetadata) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ArtifactMetadata