Struct qoi::Decoder

pub struct Decoder<R> {
    reader: R,
    header: Header,
    channels: Channels,
}

Decode QOI images from slices or from streams.

Fields

reader: R

header: Header

channels: Channels

Implementations

impl<'a> Decoder<Bytes<'a>>

pub fn new(data: &'a (impl AsRef<[u8]> + ?Sized)) -> Result<Self>

Creates a new decoder from a slice of bytes.

The header will be decoded immediately upon construction.

Note: this provides the most efficient decoding, but requires the source data to be loaded in memory in order to decode it. In order to decode from a generic stream, use Decoder::from_stream instead.

pub const fn data(&self) -> &[u8]

Returns the undecoded tail of the input slice of bytes.

impl<R: Read> Decoder<R>

pub fn from_stream(reader: R) -> Result<Self>

Creates a new decoder from a generic reader that implements Read.

The header will be decoded immediately upon construction.

Note: while it’s possible to pass a &[u8] slice here since it implements Read, it would be more efficient to use a specialized constructor instead: Decoder::new.

pub const fn reader(&self) -> &R

Returns an immutable reference to the underlying reader.

pub fn into_reader(self) -> R

Consumes the decoder and returns the underlying reader back.

impl<R: Reader> Decoder<R>

fn new_impl(reader: R) -> Result<Self>

pub const fn with_channels(self, channels: Channels) -> Self

Returns a new decoder with modified number of channels.

By default, the number of channels in the decoded image will be equal to whatever is specified in the header. However, it is also possible to decode RGB into RGBA (in which case the alpha channel will be set to 255), and vice versa (in which case the alpha channel will be ignored).

pub const fn channels(&self) -> Channels

Returns the number of channels in the decoded image.

Note: this may differ from the number of channels specified in the header.

pub const fn header(&self) -> &Header

Returns the decoded image header.

pub const fn required_buf_len(&self) -> usize

The number of bytes the decoded image will take.

Can be used to pre-allocate the buffer to decode the image into.

pub fn decode_to_buf(&mut self, buf: impl AsMut<[u8]>) -> Result<usize>

Decodes the image to a pre-allocated buffer and returns the number of bytes written.

The minimum size of the buffer can be found via Decoder::required_buf_len.

pub fn decode_to_vec(&mut self) -> Result<Vec<u8>>

Decodes the image into a newly allocated vector of bytes and returns it.

Trait Implementations

impl<R: Clone> Clone for Decoder<R>

fn clone(&self) -> Decoder<R>

Returns a copy of the value.

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

Performs copy-assignment from source.