Enum TransferFunction

#[non_exhaustive]
#[repr(u32)]
pub enum TransferFunction {
    Bt1886 = 1,
    Gamma22 = 2,
    Gamma28 = 3,
    St240 = 4,
    ExtLinear = 5,
    Log100 = 6,
    Log316 = 7,
    Xvycc = 8,
    Srgb = 9,
    ExtSrgb = 10,
    St2084Pq = 11,
    St428 = 12,
    Hlg = 13,
    CompoundPower24 = 14,
}

Available on crate feature wayland and Linux only.

named transfer functions

Named transfer functions used to represent well-known transfer characteristics of displays.

A value of 0 is invalid and will never be present in the list of enums.

See appendix.md for the formulae.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Bt1886 = 1

BT.1886 display transfer characteristic

Rec. ITU-R BT.1886 is the display transfer characteristic assumed by

• Rec. ITU-R BT.601-7 525 and 625
• Rec. ITU-R BT.709-6
• Rec. ITU-R BT.2020-2

This TF implies these default luminances from Rec. ITU-R BT.2035:

• primary color volume minimum: 0.01 cd/m²
• primary color volume maximum: 100 cd/m²
• reference white: 100 cd/m²

Gamma22 = 2

Assumed display gamma 2.2 transfer function

Transfer characteristics as defined by

• Rec. ITU-R BT.470-6 System M (historical)
• United States National Television System Committee 1953 Recommendation for transmission standards for color television
• United States Federal Communications Commission (2003) Title 47 Code of Federal Regulations 73.682 (a) (20)
• Rec. ITU-R BT.1700-0 625 PAL and 625 SECAM
• IEC 61966-2-1 (reference display)

Gamma28 = 3

Assumed display gamma 2.8 transfer function

Transfer characteristics as defined by

• Rec. ITU-R BT.470-6 System B, G (historical)

St240 = 4

SMPTE ST 240 transfer function

Transfer characteristics as defined by

• SMPTE ST 240 (1999)

ExtLinear = 5

extended linear transfer function

Linear transfer function defined over all real numbers. Normalised electrical values are equal the normalised optical values.

Log100 = 6

logarithmic 100:1 transfer function

Logarithmic transfer characteristic (100:1 range).

Log316 = 7

logarithmic (100*Sqrt(10) : 1) transfer function

Logarithmic transfer characteristic (100 * Sqrt(10) : 1 range).

Xvycc = 8

IEC 61966-2-4 transfer function

Transfer characteristics as defined by

• IEC 61966-2-4

Srgb = 9

Deprecated (ambiguous sRGB transfer function)

Transfer characteristics as defined by

• IEC 61966-2-1 sRGB

As a rule of thumb, use gamma22 for video, motion picture and computer graphics, or compound_power_2_4 for ICC calibrated print workflows.

ExtSrgb = 10

Deprecated (Extended sRGB piece-wise transfer function)

Transfer characteristics as defined by

• IEC 61966-2-1 sYCC

St2084Pq = 11

perceptual quantizer transfer function

Transfer characteristics as defined by

• SMPTE ST 2084 (2014) for 10-, 12-, 14- and 16-bit systems
• Rec. ITU-R BT.2100-2 perceptual quantization (PQ) system

This TF implies these default luminances

• primary color volume minimum: 0.005 cd/m²
• primary color volume maximum: 10000 cd/m²
• reference white: 203 cd/m²

The difference between the primary color volume minimum and maximum must be approximately 10000 cd/m² as that is the swing of the EOTF defined by ST 2084 and BT.2100. The default value for the reference white is a protocol addition: it is suggested by Report ITU-R BT.2408-7 and is not part of ST 2084 or BT.2100.

St428 = 12

SMPTE ST 428 transfer function

Transfer characteristics as defined by

• SMPTE ST 428-1 (2019)

Hlg = 13

hybrid log-gamma transfer function

Transfer characteristics as defined by

• ARIB STD-B67 (2015)
• Rec. ITU-R BT.2100-2 hybrid log-gamma (HLG) system

This TF implies these default luminances

• primary color volume minimum: 0.005 cd/m²
• primary color volume maximum: 1000 cd/m²
• reference white: 203 cd/m²

HLG is a relative display-referred signal with a specified non-linear mapping to the display peak luminance (the HLG OOTF). All absolute luminance values used here for HLG assume a 1000 cd/m² peak display.

The default value for the reference white is a protocol addition: it is suggested by Report ITU-R BT.2408-7 and is not part of ARIB STD-B67 or BT.2100.

CompoundPower24 = 14

IEC 61966-2-1 encoding function

Encoding characteristics as defined by IEC 61966-2-1, for displays that invert the encoding function.

Trait Implementations

impl Clone for TransferFunction

fn clone(&self) -> TransferFunction

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TransferFunction

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

Formats the value using the given formatter.

impl Hash for TransferFunction

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

where __H: Hasher,

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 Ord for TransferFunction

fn cmp(&self, other: &TransferFunction) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for TransferFunction

fn eq(&self, other: &TransferFunction) -> 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 PartialOrd for TransferFunction

fn partial_cmp(&self, other: &TransferFunction) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl TryFrom<u32> for TransferFunction

type Error = ()

The type returned in the event of a conversion error.

fn try_from(val: u32) -> Result<TransferFunction, ()>

Performs the conversion.

impl Copy for TransferFunction

impl Eq for TransferFunction

impl StructuralPartialEq for TransferFunction