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Jpeg-6b
transupp.h
Go to the documentation of this file.
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/*
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* transupp.h
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*
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* Copyright (C) 1997, Thomas G. Lane.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains declarations for image transformation routines and
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* other utility code used by the jpegtran sample application. These are
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* NOT part of the core JPEG library. But we keep these routines separate
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* from jpegtran.c to ease the task of maintaining jpegtran-like programs
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* that have other user interfaces.
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*
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* NOTE: all the routines declared here have very specific requirements
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* about when they are to be executed during the reading and writing of the
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* source and destination files. See the comments in transupp.c, or see
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* jpegtran.c for an example of correct usage.
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*/
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/* If you happen not to want the image transform support, disable it here */
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#ifndef TRANSFORMS_SUPPORTED
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#define TRANSFORMS_SUPPORTED 1
/* 0 disables transform code */
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#endif
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/* Short forms of external names for systems with brain-damaged linkers. */
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#ifdef NEED_SHORT_EXTERNAL_NAMES
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#define jtransform_request_workspace jTrRequest
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#define jtransform_adjust_parameters jTrAdjust
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#define jtransform_execute_transformation jTrExec
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#define jcopy_markers_setup jCMrkSetup
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#define jcopy_markers_execute jCMrkExec
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#endif
/* NEED_SHORT_EXTERNAL_NAMES */
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/*
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* Codes for supported types of image transformations.
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*/
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typedef
enum
{
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JXFORM_NONE
,
/* no transformation */
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JXFORM_FLIP_H
,
/* horizontal flip */
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JXFORM_FLIP_V
,
/* vertical flip */
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JXFORM_TRANSPOSE
,
/* transpose across UL-to-LR axis */
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JXFORM_TRANSVERSE
,
/* transpose across UR-to-LL axis */
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JXFORM_ROT_90
,
/* 90-degree clockwise rotation */
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JXFORM_ROT_180
,
/* 180-degree rotation */
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JXFORM_ROT_270
/* 270-degree clockwise (or 90 ccw) */
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}
JXFORM_CODE
;
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/*
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* Although rotating and flipping data expressed as DCT coefficients is not
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* hard, there is an asymmetry in the JPEG format specification for images
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* whose dimensions aren't multiples of the iMCU size. The right and bottom
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* image edges are padded out to the next iMCU boundary with junk data; but
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* no padding is possible at the top and left edges. If we were to flip
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* the whole image including the pad data, then pad garbage would become
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* visible at the top and/or left, and real pixels would disappear into the
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* pad margins --- perhaps permanently, since encoders & decoders may not
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* bother to preserve DCT blocks that appear to be completely outside the
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* nominal image area. So, we have to exclude any partial iMCUs from the
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* basic transformation.
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*
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* Transpose is the only transformation that can handle partial iMCUs at the
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* right and bottom edges completely cleanly. flip_h can flip partial iMCUs
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* at the bottom, but leaves any partial iMCUs at the right edge untouched.
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* Similarly flip_v leaves any partial iMCUs at the bottom edge untouched.
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* The other transforms are defined as combinations of these basic transforms
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* and process edge blocks in a way that preserves the equivalence.
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*
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* The "trim" option causes untransformable partial iMCUs to be dropped;
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* this is not strictly lossless, but it usually gives the best-looking
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* result for odd-size images. Note that when this option is active,
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* the expected mathematical equivalences between the transforms may not hold.
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* (For example, -rot 270 -trim trims only the bottom edge, but -rot 90 -trim
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* followed by -rot 180 -trim trims both edges.)
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*
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* We also offer a "force to grayscale" option, which simply discards the
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* chrominance channels of a YCbCr image. This is lossless in the sense that
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* the luminance channel is preserved exactly. It's not the same kind of
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* thing as the rotate/flip transformations, but it's convenient to handle it
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* as part of this package, mainly because the transformation routines have to
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* be aware of the option to know how many components to work on.
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*/
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typedef
struct
{
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/* Options: set by caller */
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JXFORM_CODE
transform
;
/* image transform operator */
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boolean
trim
;
/* if TRUE, trim partial MCUs as needed */
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boolean
force_grayscale
;
/* if TRUE, convert color image to grayscale */
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/* Internal workspace: caller should not touch these */
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int
num_components
;
/* # of components in workspace */
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jvirt_barray_ptr
*
workspace_coef_arrays
;
/* workspace for transformations */
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}
jpeg_transform_info
;
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#if TRANSFORMS_SUPPORTED
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/* Request any required workspace */
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EXTERN
(
void
) jtransform_request_workspace
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JPP
((
j_decompress_ptr
srcinfo,
jpeg_transform_info
*
info
));
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/* Adjust output image parameters */
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EXTERN
(
jvirt_barray_ptr
*) jtransform_adjust_parameters
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JPP
((
j_decompress_ptr
srcinfo,
j_compress_ptr
dstinfo
,
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jvirt_barray_ptr
*src_coef_arrays,
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jpeg_transform_info
*info));
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/* Execute the actual transformation, if any */
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EXTERN
(
void
) jtransform_execute_transformation
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JPP
((
j_decompress_ptr
srcinfo,
j_compress_ptr
dstinfo,
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jvirt_barray_ptr
*src_coef_arrays,
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jpeg_transform_info
*info));
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#endif
/* TRANSFORMS_SUPPORTED */
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/*
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* Support for copying optional markers from source to destination file.
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*/
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typedef
enum
{
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JCOPYOPT_NONE
,
/* copy no optional markers */
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JCOPYOPT_COMMENTS
,
/* copy only comment (COM) markers */
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JCOPYOPT_ALL
/* copy all optional markers */
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}
JCOPY_OPTION
;
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#define JCOPYOPT_DEFAULT JCOPYOPT_COMMENTS
/* recommended default */
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/* Setup decompression object to save desired markers in memory */
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EXTERN
(
void
)
jcopy_markers_setup
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JPP
((
j_decompress_ptr
srcinfo, JCOPY_OPTION
option
));
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/* Copy markers saved in the given source object to the destination object */
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EXTERN
(
void
)
jcopy_markers_execute
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JPP
((
j_decompress_ptr
srcinfo,
j_compress_ptr
dstinfo,
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JCOPY_OPTION option));
JXFORM_ROT_270
Definition:
transupp.h:48
JXFORM_NONE
Definition:
transupp.h:41
JXFORM_FLIP_H
Definition:
transupp.h:42
JCOPYOPT_ALL
Definition:
transupp.h:124
option
JCOPY_OPTION option
Definition:
transupp.h:131
dstinfo
j_compress_ptr dstinfo
Definition:
transupp.h:134
jcopy_markers_execute
jcopy_markers_execute(j_decompress_ptr srcinfo, j_compress_ptr dstinfo, JCOPY_OPTION option)
Definition:
transupp.c:886
jpeg_transform_info
Definition:
transupp.h:86
jvirt_barray_control
Definition:
jmemmgr.c:166
jpeg_transform_info::force_grayscale
boolean force_grayscale
Definition:
transupp.h:90
jpeg_transform_info::transform
JXFORM_CODE transform
Definition:
transupp.h:88
JCOPYOPT_COMMENTS
Definition:
transupp.h:123
JXFORM_ROT_180
Definition:
transupp.h:47
JCOPYOPT_NONE
Definition:
transupp.h:122
JXFORM_TRANSPOSE
Definition:
transupp.h:44
JPP
#define JPP(arglist)
Definition:
jpeglib.h:818
jpeg_transform_info::num_components
int num_components
Definition:
transupp.h:93
jpeg_compress_struct
Definition:
jpeglib.h:268
info
backing_store_ptr info
Definition:
jmemsys.h:181
JXFORM_CODE
JXFORM_CODE
Definition:
transupp.h:40
EXTERN
EXTERN(void) jcopy_markers_setup JPP((j_decompress_ptr srcinfo
JXFORM_ROT_90
Definition:
transupp.h:46
jcopy_markers_setup
jcopy_markers_setup(j_decompress_ptr srcinfo, JCOPY_OPTION option)
Definition:
transupp.c:861
jpeg_transform_info::trim
boolean trim
Definition:
transupp.h:89
jpeg_decompress_struct
Definition:
jpeglib.h:411
jpeg_transform_info::workspace_coef_arrays
jvirt_barray_ptr * workspace_coef_arrays
Definition:
transupp.h:94
JCOPY_OPTION
JCOPY_OPTION
Definition:
transupp.h:121
JXFORM_FLIP_V
Definition:
transupp.h:43
JXFORM_TRANSVERSE
Definition:
transupp.h:45
openhrp3
Author(s): AIST, General Robotix Inc., Nakamura Lab of Dept. of Mechano Informatics at University of Tokyo
autogenerated on Sat May 8 2021 02:42:41