TurboJPEG 3.0.1
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Data Fields
tjtransform Struct Reference

Lossless transform. More...

#include <turbojpeg.h>

Data Fields

tjregion r
 Cropping region.
 
int op
 One of the transform operations.
 
int options
 The bitwise OR of one of more of the transform options.
 
void * data
 Arbitrary data that can be accessed within the body of the callback function.
 
int(* customFilter )(short *coeffs, tjregion arrayRegion, tjregion planeRegion, int componentID, int transformID, struct tjtransform *transform)
 A callback function that can be used to modify the DCT coefficients after they are losslessly transformed but before they are transcoded to a new JPEG image.
 

Detailed Description

Lossless transform.

Field Documentation

◆ customFilter

int(* tjtransform::customFilter) (short *coeffs, tjregion arrayRegion, tjregion planeRegion, int componentID, int transformID, struct tjtransform *transform)

A callback function that can be used to modify the DCT coefficients after they are losslessly transformed but before they are transcoded to a new JPEG image.

This allows for custom filters or other transformations to be applied in the frequency domain.

Parameters
coeffspointer to an array of transformed DCT coefficients. (NOTE: this pointer is not guaranteed to be valid once the callback returns, so applications wishing to hand off the DCT coefficients to another function or library should make a copy of them within the body of the callback.)
arrayRegiontjregion structure containing the width and height of the array pointed to by coeffs as well as its offset relative to the component plane. TurboJPEG implementations may choose to split each component plane into multiple DCT coefficient arrays and call the callback function once for each array.
planeRegiontjregion structure containing the width and height of the component plane to which coeffs belongs
componentIDID number of the component plane to which coeffs belongs. (Y, Cb, and Cr have, respectively, ID's of 0, 1, and 2 in typical JPEG images.)
transformIDID number of the transformed image to which coeffs belongs. This is the same as the index of the transform in the transforms array that was passed to tj3Transform().
transforma pointer to a tjtransform structure that specifies the parameters and/or cropping region for this transform
Returns
0 if the callback was successful, or -1 if an error occurred.

◆ data

void* tjtransform::data

Arbitrary data that can be accessed within the body of the callback function.

◆ op

int tjtransform::op

One of the transform operations.

◆ options

int tjtransform::options

The bitwise OR of one of more of the transform options.

◆ r

tjregion tjtransform::r

Cropping region.


The documentation for this struct was generated from the following file: