Struct mozjpeg::Compress

pub struct Compress { /* fields omitted */ }

Create a new JPEG file from pixels

Wrapper for jpeg_compress_struct

Implementations

impl Compress

pub fn new(color_space: ColorSpace) -> Compress

Compress image using input in this colorspace

By default errors cause panic and unwind through the C code, which strictly speaking is not guaranteed to work in Rust (but seems to work fine, at least in x86/64).

pub fn new_err(err: ErrorMgr, color_space: ColorSpace) -> Compress

Use a specific error handler instead of the default panicking one

color_space refers to input color space

pub fn start_compress(&mut self)

Settings can't be changed after this call

pub fn write_marker(&mut self, marker: Marker, data: &[u8])

Add a marker to compressed file

Data is max 64KB

pub fn components_mut(&mut self) -> &mut [CompInfo]

Expose components for modification, e.g. to set chroma subsampling

pub fn components(&self) -> &[CompInfo]

Read-only view of component information

pub fn write_scanlines(&mut self, image_src: &[u8]) -> bool

Returns true if all lines in image_src (not necessarily all lines of the image) were written

pub fn write_raw_data(&mut self, image_src: &[&[u8]]) -> bool

Advanced. Only possible after set_raw_data_in(). Write YCbCr blocks pixels instead of usual color space

See raw_data_in in libjpeg docs

pub fn set_color_space(&mut self, color_space: ColorSpace)

Set color space of JPEG being written, different from input color space

See jpeg_set_colorspace in libjpeg docs

pub fn set_size(&mut self, width: usize, height: usize)

Image size of the input

pub fn set_gamma(&mut self, gamma: f64)

👎 Deprecated:

it doesn't do anything

libjpeg's input_gamma = image gamma of input image

pub fn set_optimize_scans(&mut self, opt: bool)

If true, it will use MozJPEG's scan optimization. Makes progressive image files smaller.

pub fn set_optimize_coding(&mut self, opt: bool)

Set to false to make files larger for no reason

pub fn set_use_scans_in_trellis(&mut self, opt: bool)

Specifies whether multiple scans should be considered during trellis quantization.

pub fn set_progressive_mode(&mut self)

You can only turn it on

pub fn set_scan_optimization_mode(&mut self, mode: ScanMode)

One scan for all components looks best. Other options may flash grayscale or green images.

pub fn set_fastest_defaults(&mut self)

Reset to libjpeg v6 settings

It gives files identical with libjpeg-turbo

pub fn set_raw_data_in(&mut self, opt: bool)

Advanced. See raw_data_in in libjpeg docs.

pub fn set_quality(&mut self, quality: f32)

Set image quality. Values 60-80 are recommended.

pub fn set_luma_qtable(&mut self, qtable: &QTable)

Instead of quality setting, use a specific quantization table.

pub fn set_chroma_qtable(&mut self, qtable: &QTable)

Instead of quality setting, use a specific quantization table for color.

pub fn set_mem_dest(&mut self)

Write to in-memory buffer

pub fn finish_compress(&mut self)

Finalize compression. In case of progressive files, this may actually start processing.

pub fn data_as_mut_slice(&mut self) -> Result<&[u8], ()>

If set_mem_dest() was enabled, this is the result

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

If set_mem_dest() was enabled, this is the result. Can be called once only.

Trait Implementations

impl Drop for Compress

pub fn drop(&mut self)

Executes the destructor for this type.