Struct jpeg_decoder::decoder::Decoder

pub struct Decoder<R> {

    reader: R,
    frame: Option<FrameInfo>,
    dc_huffman_tables: Vec<Option<HuffmanTable>>,
    ac_huffman_tables: Vec<Option<HuffmanTable>>,
    quantization_tables: [Option<Arc<[u16; 64]>>; 4],
    restart_interval: u16,
    adobe_color_transform: Option<AdobeColorTransform>,
    color_transform: Option<ColorTransform>,
    is_jfif: bool,
    is_mjpeg: bool,
    icc_markers: Vec<IccChunk>,
    exif_data: Option<Vec<u8>>,
    xmp_data: Option<Vec<u8>>,
    psir_data: Option<Vec<u8>>,
    coefficients: Vec<Vec<i16>>,
    coefficients_finished: [u64; 4],
    decoding_buffer_size_limit: usize,
}

JPEG decoder

Fields

reader: R

frame: Option<FrameInfo>

dc_huffman_tables: Vec<Option<HuffmanTable>>

ac_huffman_tables: Vec<Option<HuffmanTable>>

quantization_tables: [Option<Arc<[u16; 64]>>; 4]

restart_interval: u16

adobe_color_transform: Option<AdobeColorTransform>

color_transform: Option<ColorTransform>

is_jfif: bool

is_mjpeg: bool

icc_markers: Vec<IccChunk>

exif_data: Option<Vec<u8>>

xmp_data: Option<Vec<u8>>

psir_data: Option<Vec<u8>>

coefficients: Vec<Vec<i16>>

coefficients_finished: [u64; 4]

decoding_buffer_size_limit: usize

Implementations

impl<R: Read> Decoder<R>

pub fn decode_scan_lossless( &mut self, frame: &FrameInfo, scan: &ScanInfo, ) -> Result<(Option<Marker>, Vec<Vec<u16>>), Error>

decode_scan_lossless

impl<R: Read> Decoder<R>

pub fn new(reader: R) -> Decoder<R>

Creates a new Decoder using the reader reader.

pub fn set_color_transform(&mut self, transform: ColorTransform)

Colour transform to use when decoding the image. App segments relating to colour transforms will be ignored.

pub fn set_max_decoding_buffer_size(&mut self, max: usize)

Set maximum buffer size allowed for decoded images

pub fn info(&self) -> Option<ImageInfo>

Returns metadata about the image.

The returned value will be None until a call to either read_info or decode has returned Ok.

pub fn exif_data(&self) -> Option<&[u8]>

Returns raw exif data, starting at the TIFF header, if the image contains any.

The returned value will be None until a call to decode has returned Ok.

pub fn xmp_data(&self) -> Option<&[u8]>

Returns the raw XMP packet if there is any.

The returned value will be None until a call to decode has returned Ok.

pub fn icc_profile(&self) -> Option<Vec<u8>>

Returns the embeded icc profile if the image contains one.

fn select_worker( frame: &FrameInfo, worker_preference: PreferWorkerKind, ) -> PreferWorkerKind

Heuristic to avoid starting thread, synchronization if we expect a small amount of parallelism to be utilized.

pub fn read_info(&mut self) -> Result<(), Error>

Tries to read metadata from the image without decoding it.

If successful, the metadata can be obtained using the info method.

pub fn scale( &mut self, requested_width: u16, requested_height: u16, ) -> Result<(u16, u16), Error>

Configure the decoder to scale the image during decoding.

This efficiently scales the image by the smallest supported scale factor that produces an image larger than or equal to the requested size in at least one axis. The currently implemented scale factors are 1/8, 1/4, 1/2 and 1.

To generate a thumbnail of an exact size, pass the desired size and then scale to the final size using a traditional resampling algorithm.

pub fn decode(&mut self) -> Result<Vec<u8>, Error>

Decodes the image and returns the decoded pixels if successful.

fn decode_internal( &mut self, stop_after_metadata: bool, worker_scope: &WorkerScope, ) -> Result<Vec<u8>, Error>

fn decode_planes( &mut self, worker: &mut dyn Worker, planes: Vec<Vec<u8>>, planes_u16: Vec<Vec<u16>>, ) -> Result<Vec<u8>, Error>

fn determine_color_transform(&self) -> ColorTransform

fn read_marker(&mut self) -> Result<Marker, Error>

fn decode_scan( &mut self, frame: &FrameInfo, scan: &ScanInfo, worker: &mut dyn Worker, finished: &[bool; 4], ) -> Result<(Option<Marker>, Option<Vec<Vec<u8>>>), Error>