Struct turbojpeg::Decompressor

pub struct Decompressor { /* private fields */ }

Decompresses JPEG data into raw pixels.

Implementations

impl Decompressor

pub fn new() -> Result<Decompressor>

Create a new decompressor instance.

pub fn read_header(&mut self, jpeg_data: &[u8]) -> Result<DecompressHeader>

Read the JPEG header without decompressing the image.

Example

// read JPEG data from file
let jpeg_data = std::fs::read("examples/parrots.jpg")?;

// initialize a decompressor
let mut decompressor = turbojpeg::Decompressor::new()?;

// read the JPEG header
let header = decompressor.read_header(&jpeg_data)?;
assert_eq!((header.width, header.height), (384, 256));

pub fn decompress( &mut self, jpeg_data: &[u8], output: Image<&mut [u8]> ) -> Result<()>

Decompress a JPEG image in jpeg_data into output.

The decompressed image is stored in the pixel data of the given output image, which must be fully initialized by the caller. Use read_header() to determine the image size before calling this method.

Example

// read JPEG data from file
let jpeg_data = std::fs::read("examples/parrots.jpg")?;

// initialize a decompressor
let mut decompressor = turbojpeg::Decompressor::new()?;

// read the JPEG header
let header = decompressor.read_header(&jpeg_data)?;

// initialize the image (Image<Vec<u8>>)
let mut image = turbojpeg::Image {
    pixels: vec![0; 4 * header.width * header.height],
    width: header.width,
    pitch: 4 * header.width, // size of one image row in memory
    height: header.height,
    format: turbojpeg::PixelFormat::RGBA,
};

// decompress the JPEG into the image
// (we use as_deref_mut() to convert from &mut Image<Vec<u8>> into Image<&mut [u8]>)
decompressor.decompress(&jpeg_data, image.as_deref_mut())?;
assert_eq!(&image.pixels[0..4], &[122, 118, 89, 255]);

pub fn decompress_to_yuv( &mut self, jpeg_data: &[u8], output: YuvImage<&mut [u8]> ) -> Result<()>

Decompress a JPEG image in jpeg_data into output as YUV without changing color space.

The decompressed image is stored in the pixel data of the given output image, which must be fully initialized by the caller. Use read_header() to determine the image size before calling this method.

Example

// read JPEG data from file
let jpeg_data = std::fs::read("examples/parrots.jpg")?;

// initialize a decompressor
let mut decompressor = turbojpeg::Decompressor::new()?;

// read the JPEG header
let header = decompressor.read_header(&jpeg_data)?;
// calculate YUV pixels length
let align = 4;
let yuv_pixels_len = turbojpeg::yuv_pixels_len(header.width, align, header.height, header.subsamp);

// initialize the image (YuvImage<Vec<u8>>)
let mut image = turbojpeg::YuvImage {
    pixels: vec![0; yuv_pixels_len.unwrap()],
    width: header.width,
    align,
    height: header.height,
    subsamp: header.subsamp,
};

// decompress the JPEG into the image
// (we use as_deref_mut() to convert from &mut YuvImage<Vec<u8>> into YuvImage<&mut [u8]>)
decompressor.decompress_to_yuv(&jpeg_data, image.as_deref_mut())?;
assert_eq!(&image.pixels[0..4], &[116, 117, 118, 119]);

Trait Implementations

impl Debug for Decompressor

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

Formats the value using the given formatter.

impl Send for Decompressor