Current File : //usr/include/OpenEXR/openexr_coding.h
/*
** SPDX-License-Identifier: BSD-3-Clause
** Copyright Contributors to the OpenEXR Project.
*/
#ifndef OPENEXR_CORE_CODING_H
#define OPENEXR_CORE_CODING_H
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* Enum for use in a custom allocator in the encode / decode pipelines
* (i.e. so the implementor knows whether to allocate on which device
* based on the buffer disposition)
*/
enum transcoding_pipeline_buffer_id
{
EXR_TRANSCODE_BUFFER_PACKED,
EXR_TRANSCODE_BUFFER_UNPACKED,
EXR_TRANSCODE_BUFFER_COMPRESSED,
EXR_TRANSCODE_BUFFER_SCRATCH1,
EXR_TRANSCODE_BUFFER_SCRATCH2,
EXR_TRANSCODE_BUFFER_PACKED_SAMPLES,
EXR_TRANSCODE_BUFFER_SAMPLES
};
/** @brief Structure for negotiating buffers when decoding / encoding
* chunks of data
*
* This is generic and meant to negotiate exr data bi-directionally,
* in that the same structure is used for both decoding and encoding
* chunks for read and write, respectively.
*
* The first half of the structure will be filled by the library, and
* the caller is expected to fill the second half appropriately.
*/
typedef struct
{
/**************************************************
* Elements below are populated by the library when
* decoding is initialized / updated and must be left
* untouched when using the default decoder routines
**************************************************/
/** channel name
*
* This is provided as a convenient reference. Do not free, this
* refers to the internal data structure in the context.
*/
const char* channel_name;
/** number of lines for this channel in this chunk
*
* May be 0 or less than overall image height based on sampling
* (i.e. when in 4:2:0 type sampling)
*/
int32_t height;
/** width in pixel count
*
* May be 0 or less than overall image width based on sampling
* (i.e. 4:2:2 will have some channels have fewer values)
*/
int32_t width;
/** horizontal subsampling information */
int32_t x_samples;
/** vertical subsampling information */
int32_t y_samples;
/** linear flag from channel definition (used by b44)*/
uint8_t p_linear;
/**
* how many bytes per pixel this channel consumes (i.e. 2 for
* float16, 4 for float32 / uint32)
*/
int8_t bytes_per_element;
/** small form of exr_pixel_type_t enum (EXR_PIXEL_UINT/HALF/FLOAT) */
uint16_t data_type;
/**************************************************
* Elements below must be edited by the caller
* to control encoding / decoding
**************************************************/
/**
* how many bytes per pixel the input is or output should be
* (i.e. 2 for float16, 4 for float32 / uint32). Defaults to same
* size as input
*/
int16_t user_bytes_per_element;
/** small form of exr_pixel_type_t enum
* (EXR_PIXEL_UINT/HALF/FLOAT). Defaults to same type as input */
uint16_t user_data_type;
/** increment to get to next pixel
*
* This is in bytes. Must be specified when the decode pointer is
* specified (and always for encode).
*
* This is useful for implementing transcoding generically of
* planar or interleaved data. For planar data, where the layout
* is RRRRRGGGGGBBBBB, you can pass in 1 * bytes per component
*/
int32_t user_pixel_stride;
/**
* When lines > 1 for a chunk, this is the increment used to get
* from beginning of line to beginning of next line.
*
* This is in bytes. Must be specified when the decode pointer is
* specified (and always for encode).
*/
int32_t user_line_stride;
/**
* This data member has different requirements reading vs
* writing. When reading, if this is left as NULL, the channel
* will be skipped during read and not filled in. During a write
* operation, this pointer is considered const and not
* modified. To make this more clear, a union is used here.
*/
union
{
uint8_t* decode_to_ptr;
const uint8_t* encode_from_ptr;
};
} exr_coding_channel_info_t;
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* OPENEXR_CORE_CODING_H */
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