text: /* +------------------------------------------------------------------------+
     |                     Mobile Robot Programming Toolkit (MRPT)            |
     |                          http://www.mrpt.org/                          |
     |                                                                        |
     | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
     | See: http://www.mrpt.org/Authors - All rights reserved.                |
     | Released under BSD License. See details in http://www.mrpt.org/License |
     +------------------------------------------------------------------------+ */
  
  /* If you happen not to want the image transform support, disable it here */
  #ifndef TRANSFORMS_SUPPORTED
  #define TRANSFORMS_SUPPORTED 1 /* 0 disables transform code */
  #endif
  
  /* Short forms of external names for systems with brain-damaged linkers. */
  
  #ifdef NEED_SHORT_EXTERNAL_NAMES
  #define jtransform_request_workspace jTrRequest
  #define jtransform_adjust_parameters jTrAdjust
  #define jtransform_execute_transformation jTrExec
  #define jcopy_markers_setup jCMrkSetup
  #define jcopy_markers_execute jCMrkExec
  #endif /* NEED_SHORT_EXTERNAL_NAMES */
  
  /*
   * Codes for supported types of image transformations.
   */
  
  typedef enum {
  	JXFORM_NONE, /* no transformation */
  	JXFORM_FLIP_H, /* horizontal flip */
  	JXFORM_FLIP_V, /* vertical flip */
  	JXFORM_TRANSPOSE, /* transpose across UL-to-LR axis */
  	JXFORM_TRANSVERSE, /* transpose across UR-to-LL axis */
  	JXFORM_ROT_90, /* 90-degree clockwise rotation */
  	JXFORM_ROT_180, /* 180-degree rotation */
  	JXFORM_ROT_270 /* 270-degree clockwise (or 90 ccw) */
  } JXFORM_CODE;
  
  /*
   * Although rotating and flipping data expressed as DCT coefficients is not
   * hard, there is an asymmetry in the JPEG format specification for images
   * whose dimensions aren't multiples of the iMCU size.  The right and bottom
   * image edges are padded out to the next iMCU boundary with junk data; but
   * no padding is possible at the top and left edges.  If we were to flip
   * the whole image including the pad data, then pad garbage would become
   * visible at the top and/or left, and real pixels would disappear into the
   * pad margins --- perhaps permanently, since encoders & decoders may not
   * bother to preserve DCT blocks that appear to be completely outside the
   * nominal image area.  So, we have to exclude any partial iMCUs from the
   * basic transformation.
   *
   * Transpose is the only transformation that can handle partial iMCUs at the
   * right and bottom edges completely cleanly.  flip_h can flip partial iMCUs
   * at the bottom, but leaves any partial iMCUs at the right edge untouched.
   * Similarly flip_v leaves any partial iMCUs at the bottom edge untouched.
   * The other transforms are defined as combinations of these basic transforms
   * and process edge blocks in a way that preserves the equivalence.
   *
   * The "trim" option causes untransformable partial iMCUs to be dropped;
   * this is not strictly lossless, but it usually gives the best-looking
   * result for odd-size images.  Note that when this option is active,
   * the expected mathematical equivalences between the transforms may not hold.
   * (For example, -rot 270 -trim trims only the bottom edge, but -rot 90 -trim
   * followed by -rot 180 -trim trims both edges.)
   *
   * We also offer a "force to grayscale" option, which simply discards the
   * chrominance channels of a YCbCr image.  This is lossless in the sense that
   * the luminance channel is preserved exactly.  It's not the same kind of
   * thing as the rotate/flip transformations, but it's convenient to handle it
   * as part of this package, mainly because the transformation routines have to
   * be aware of the option to know how many components to work on.
   */
  
  typedef struct
  {
  	/* Options: set by caller */
  	JXFORM_CODE transform; /* image transform operator */
  	boolean trim; /* if TRUE, trim partial MCUs as needed */
  	boolean force_grayscale; /* if TRUE, convert color image to grayscale */
  
  	/* Internal workspace: caller should not touch these */
  	int num_components; /* # of components in workspace */
  	jvirt_barray_ptr* workspace_coef_arrays; /* workspace for transformations */
  } jpeg_transform_info;
  
  #if TRANSFORMS_SUPPORTED
  
  /* Request any required workspace */
  EXTERN(void)
  jtransform_request_workspace JPP(
  	(j_decompress_ptr srcinfo, jpeg_transform_info* info));
  /* Adjust output image parameters */
  EXTERN(jvirt_barray_ptr*)
  jtransform_adjust_parameters JPP(
  	(j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
  	 jvirt_barray_ptr* src_coef_arrays, jpeg_transform_info* info));
  /* Execute the actual transformation, if any */
  EXTERN(void)
  jtransform_execute_transformation JPP(
  	(j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
  	 jvirt_barray_ptr* src_coef_arrays, jpeg_transform_info* info));
  
  #endif /* TRANSFORMS_SUPPORTED */
  
  /*
   * Support for copying optional markers from source to destination file.
   */
  
  typedef enum {
  	JCOPYOPT_NONE, /* copy no optional markers */
  	JCOPYOPT_COMMENTS, /* copy only comment (COM) markers */
  	JCOPYOPT_ALL /* copy all optional markers */
  } JCOPY_OPTION;
  
  #define JCOPYOPT_DEFAULT JCOPYOPT_COMMENTS /* recommended default */
  
  /* Setup decompression object to save desired markers in memory */
  EXTERN(void)
  jcopy_markers_setup JPP((j_decompress_ptr srcinfo, JCOPY_OPTION option));
  /* Copy markers saved in the given source object to the destination object */
  EXTERN(void)
  jcopy_markers_execute JPP(
  	(j_decompress_ptr srcinfo, j_compress_ptr dstinfo, JCOPY_OPTION option));
  