Struct exr::meta::attribute::ChannelDescription

pub struct ChannelDescription {
    pub name: Text,
    pub sample_type: SampleType,
    pub quantize_linearly: bool,
    pub sampling: Vec2<usize>,
}

A single channel in an layer. Does not contain the actual pixel data, but instead merely describes it.

Fields

name: Text

One of “R”, “G”, or “B” most of the time.

sample_type: SampleType

U32, F16 or F32.

quantize_linearly: bool

This attribute only tells lossy compression methods whether this value should be quantized exponentially or linearly.

Should be false for red, green, or blue channels. Should be true for hue, chroma, saturation, or alpha channels.

sampling: Vec2<usize>

How many of the samples are skipped compared to the other channels in this layer.

Can be used for chroma subsampling for manual lossy data compression. Values other than 1 are allowed only in flat, scan-line based images. If an image is deep or tiled, x and y sampling rates for all of its channels must be 1.

Implementations

impl ChannelDescription

pub fn guess_quantization_linearity(name: &Text) -> bool

Choose whether to compress samples linearly or not, based on the channel name. Luminance-based channels will be compressed differently than linear data such as alpha.

pub fn named(name: impl Into<Text>, sample_type: SampleType) -> Self

Create a new channel with the specified properties and a sampling rate of (1,1). Automatically chooses the linearity for compression based on the channel name.

pub fn new( name: impl Into<Text>, sample_type: SampleType, quantize_linearly: bool, ) -> Self

Create a new channel with the specified properties and a sampling rate of (1,1).

pub fn subsampled_pixels(&self, dimensions: Vec2<usize>) -> usize

The count of pixels this channel contains, respecting subsampling.

pub fn subsampled_resolution(&self, dimensions: Vec2<usize>) -> Vec2<usize>

The resolution pf this channel, respecting subsampling.

pub fn byte_size(&self) -> usize

Number of bytes this would consume in an exr file.

pub fn write<W: Write>(&self, write: &mut W) -> UnitResult

Without validation, write this instance to the byte stream.

pub fn read<R: Read>(read: &mut R) -> Result<Self>

Read the value without validating.

pub fn validate( &self, allow_sampling: bool, data_window: IntegerBounds, strict: bool, ) -> UnitResult

Validate this instance.

Trait Implementations

impl Clone for ChannelDescription

fn clone(&self) -> ChannelDescription

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ChannelDescription

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

Formats the value using the given formatter.

impl Hash for ChannelDescription

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 ChannelDescription

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for ChannelDescription

impl StructuralPartialEq for ChannelDescription