| Index: third_party/libjpeg_turbo/transupp.h
|
| ===================================================================
|
| --- third_party/libjpeg_turbo/transupp.h (revision 0)
|
| +++ third_party/libjpeg_turbo/transupp.h (revision 0)
|
| @@ -0,0 +1,135 @@
|
| +/*
|
| + * transupp.h
|
| + *
|
| + * Copyright (C) 1997, Thomas G. Lane.
|
| + * This file is part of the Independent JPEG Group's software.
|
| + * For conditions of distribution and use, see the accompanying README file.
|
| + *
|
| + * This file contains declarations for image transformation routines and
|
| + * other utility code used by the jpegtran sample application. These are
|
| + * NOT part of the core JPEG library. But we keep these routines separate
|
| + * from jpegtran.c to ease the task of maintaining jpegtran-like programs
|
| + * that have other user interfaces.
|
| + *
|
| + * NOTE: all the routines declared here have very specific requirements
|
| + * about when they are to be executed during the reading and writing of the
|
| + * source and destination files. See the comments in transupp.c, or see
|
| + * jpegtran.c for an example of correct usage.
|
| + */
|
| +
|
| +/* 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));
|
|
|