Enum Orientation 

pub enum Orientation {
    Normal,
    FlipHorizontal,
    Rotate180,
    FlipVertical,
    Transpose,
    Rotate90,
    Transverse,
    Rotate270,
}

One of the eight orientations the EXIF/TIFF Orientation tag (274) can name.

Each variant describes the transform that makes the stored image upright. All eight are a clockwise quarter-turn rotation followed, optionally, by a horizontal mirror, which is the form Orientation::clockwise_turns and Orientation::mirrored expose and Orientation::from_parts builds from. HEIF’s rotate-then-mirror properties reduce to the same form.

Variants

Normal

EXIF 1: already upright.

FlipHorizontal

EXIF 2: mirror left to right.

Rotate180

EXIF 3: rotate 180 degrees.

FlipVertical

EXIF 4: mirror top to bottom.

Transpose

EXIF 5: mirror across the top-left to bottom-right diagonal.

Rotate90

EXIF 6: rotate 90 degrees clockwise.

Transverse

EXIF 7: mirror across the top-right to bottom-left diagonal.

Rotate270

EXIF 8: rotate 270 degrees clockwise, i.e. 90 anticlockwise.

Implementations

impl Orientation

pub const fn from_exif(value: u16) -> Option<Self>

The orientation an EXIF Orientation value names, or None for a value outside 1–8.

pub const fn exif(self) -> u8

The EXIF Orientation value, 1–8.

pub const fn from_parts(turns: u8, mirrored: bool) -> Self

Rotate turns quarter turns clockwise (taken modulo 4), then mirror left to right if mirrored.

pub const fn clockwise_turns(self) -> u8

Clockwise quarter turns to apply first, 0–3.

pub const fn mirrored(self) -> bool

Whether a left-to-right mirror follows the rotation.

pub const fn transposes(self) -> bool

Whether displaying upright exchanges width and height.

pub fn from_exif_block(exif: &[u8]) -> Option<Self>

Read the Orientation tag from an EXIF block.

exif is the TIFF structure EXIF is made of, optionally behind the Exif\0\0 identifier a JPEG APP1 segment carries. PNG’s eXIf and WebP’s EXIF chunk are specified without the identifier, but writers that copy it across from a JPEG are common, so both are accepted.

A missing tag, an out-of-range value or a malformed block all yield None rather than an error: broken metadata is not a broken image, and refusing to decode a photograph over it would be the wrong trade.

Trait Implementations

impl Clone for Orientation

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Orientation

impl Debug for Orientation

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

Formats the value using the given formatter.

impl Default for Orientation

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Orientation

impl Hash for Orientation

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Orientation

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Orientation