Struct JxlEncoderOutputProcessor 

#[repr(C)]
pub struct JxlEncoderOutputProcessor {
    pub opaque: *mut c_void,
    pub get_buffer: Option<unsafe extern "C" fn(opaque: *mut c_void, size: *mut usize) -> *mut c_void>,
    pub release_buffer: Option<unsafe extern "C" fn(opaque: *mut c_void, written_bytes: usize)>,
    pub seek: Option<unsafe extern "C" fn(opaque: *mut c_void, position: u64)>,
    pub set_finalized_position: Option<unsafe extern "C" fn(opaque: *mut c_void, finalized_position: u64)>,
}

The @ref JxlEncoderOutputProcessor structure provides an interface for the encoder’s output processing. Users of the library, who want to do streaming encoding, should implement the required callbacks for buffering, writing, seeking (if supported), and setting a finalized position during the encoding process.

At a high level, the processor can be in one of two states:

• With an active buffer: This indicates that a buffer has been acquired using get_buffer and encoded data can be written to it.
• Without an active buffer: In this state, no data can be written. A new buffer must be acquired after releasing any previously active buffer.

The library will not acquire more than one buffer at a given time.

The state of the processor includes position and finalized position, which have the following meaning.

• position: Represents the current position, in bytes, within the output stream where the encoded data will be written next. This position moves forward with each release_buffer call as data is written, and can also be adjusted through the optional seek callback, if provided. At this position the next write will occur.

• finalized position: A position in the output stream that ensures all bytes before this point are finalized and won’t be changed by later writes.

All fields but seek are required, seek is optional and can be NULL.

Fields

opaque: *mut c_void

Required. An opaque pointer that the client can use to store custom data. This data will be passed to the associated callback functions.

get_buffer: Option<unsafe extern "C" fn(opaque: *mut c_void, size: *mut usize) -> *mut c_void>

Required. Acquires a buffer at the current position into which the library will write the output data.

If the size argument points to 0 and the returned value is NULL, this will be interpreted as asking the output writing to stop. In such a case, the library will return an error. The client is expected to set the size of the returned buffer based on the suggested size when this function is called.

@param opaque user supplied parameters to the callback @param size points to a suggested buffer size when called; must be set to the size of the returned buffer once the function returns. @return a pointer to the acquired buffer or NULL to indicate a stop condition.

release_buffer: Option<unsafe extern "C" fn(opaque: *mut c_void, written_bytes: usize)>

Required. Notifies the user of library that the current buffer’s data has been written and can be released. This function should advance the current position of the buffer by written_bytes number of bytes.

@param opaque user supplied parameters to the callback @param written_bytes the number of bytes written to the buffer.

seek: Option<unsafe extern "C" fn(opaque: *mut c_void, position: u64)>

Optional, can be NULL Seeks to a specific position in the output. This function is optional and can be set to NULL if the output doesn’t support seeking. Can only be done when there is no buffer. Cannot be used to seek before the finalized position.

@param opaque user supplied parameters to the callback @param position the position to seek to, in bytes.

set_finalized_position: Option<unsafe extern "C" fn(opaque: *mut c_void, finalized_position: u64)>

Required. Sets a finalized position on the output data, at a specific position. Seeking will never request a position before the finalized position.

Will only be called if there is no active buffer.

@param opaque user supplied parameters to the callback @param finalized_position the position, in bytes, where the finalized position should be set.

Trait Implementations

impl Clone for JxlEncoderOutputProcessor

fn clone(&self) -> JxlEncoderOutputProcessor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for JxlEncoderOutputProcessor

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

Formats the value using the given formatter.

impl Default for JxlEncoderOutputProcessor

fn default() -> Self

Returns the “default value” for a type.

impl Copy for JxlEncoderOutputProcessor