Struct SampleInformation 

pub struct SampleInformation {
    pub bit_offset: u16,
    pub bit_length: NonZeroU8,
    pub channel_type: u8,
    pub channel_type_qualifiers: ChannelTypeQualifiers,
    pub sample_positions: [u8; 4],
    pub lower: u32,
    pub upper: u32,
}

Information about each “sample” within an image.

A “sample” consisting of a single channel of data and with a single corresponding “position” within the texel block.

See the DFD specification for more extremely verbose information.

Fields

bit_offset: u16

Offset from the beginning of the texel block in bits.

bit_length: NonZeroU8

The length of this sample in bits.

channel_type: u8

The type of channel this sample represents. This varies by ColorModel.

channel_type_qualifiers: ChannelTypeQualifiers

Qualifiers modifying the channel type.

sample_positions: [u8; 4]

The position in texels of this sample relative to the 0,0,0,0 texel in the 4D texel block.

lower: u32

The sample value that maps to the format’s logical minimum — typically 0 for unsigned formats, -1 for signed formats, or -0.5 for chroma channels in color difference models (e.g. Y′CbCr).

Together with upper, this defines how raw sample values are converted to their conceptual numeric interpretation. Values are not guaranteed to fall within this range — for example, HDR formats may define 1.0 as a nominal level well below the actual maximum. When samples should be interpreted directly as integers (unnormalized), set upper to 1 and lower to 0 (unsigned) or -1 (signed).

For integer formats, this is stored as a 32-bit integer (signed or unsigned matching the channel encoding). For floating-point formats, it is stored as a 32-bit float. For formats wider than 32 bits (e.g. 64-bit), integer values are expanded by preserving the sign bit and replicating the top non-sign bit, and float values are converted to the native representation (e.g. f32 to f64).

Examples

Format	lower	upper	Effect
R8 unorm	0	255	Maps 0–255 to 0.0–1.0
R8 snorm	-127 (0xFFFFFF81)	127	Maps -127–127 to -1.0–1.0
R8 uint	0	1	Integer value used directly
R16 sfloat	0xBF800000 (-1.0f)	0x3F800000 (1.0f)	Float range -1.0–1.0
R64 uint	0	1	Expands to 64-bit 0 and 1
R64 uint norm	0	0xFFFFFFFF	Expands to u64::MAX, maps to 0.0–1.0
BT.709 Y′ (8-bit)	16	235	Maps 16–235 to 0.0–1.0

For a very long and confusing explanation of this, please see the DFD specification

upper: u32

The sample value that maps to 1.0 (the white point), or 0.5 for chroma channels in color difference models (e.g. Y′CbCr).

See lower for more details on interpretation and encoding and examples.

Implementations

impl SampleInformation

pub const LENGTH: usize = 16

Number of bytes in a SampleInformation entry.

pub fn as_bytes(&self) -> [u8; 16]

Serializes this sample information to bytes.

pub fn from_bytes(bytes: &[u8; 16]) -> Result<Self, ParseError>

Deserializes sample information from the given bytes.

Trait Implementations

impl Clone for SampleInformation

fn clone(&self) -> SampleInformation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for SampleInformation

impl Debug for SampleInformation

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

Formats the value using the given formatter.

impl Eq for SampleInformation

impl PartialEq for SampleInformation

fn eq(&self, other: &SampleInformation) -> 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 StructuralPartialEq for SampleInformation