third-party/leptonica/src/imageio.h
/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
- 1. Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- 2. Redistributions in binary form must reproduce the above
- copyright notice, this list of conditions and the following
- disclaimer in the documentation and/or other materials
- provided with the distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
- CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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- OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*====================================================================*/
/*
* General features of image I/O in leptonica
*
* At present, there are 9 file formats for images that can be read
* and written:
* png (requires libpng, libz)
* jpeg (requires libjpeg)
* tiff (requires libtiff, libz)
* gif (requires libgif)
* webp (requires libwebp)
* jp2 (requires libopenjp2)
* bmp (no library required)
* pnm (no library required)
* spix (no library required)
* Additionally, there are two file formats for writing (only) images:
* PostScript (requires libpng, libz, libjpeg, libtiff)
* pdf (requires libpng, libz, libjpeg, libtiff)
*
* For all 9 read/write formats, leptonica provides interconversion
* between pix (with raster data) and formatted image data:
* Conversion from pix (typically compression):
* pixWrite(): pix --> file
* pixWriteStream(): pix --> filestream (aka FILE*)
* pixWriteMem(): pix --> memory buffer
* Conversion to pix (typically decompression):
* pixRead(): file --> pix
* pixReadStream(): filestream --> pix
* pixReadMem(): memory buffer --> pix
*
* Conversions for which the image data is not compressed are:
* * uncompressed tiff (IFF_TIFF)
* * bmp
* * pnm
* * spix (fast serialization that copies the pix raster data)
*
* The image header (metadata) information can be read from either
* the compressed file or a memory buffer, for all 9 formats.
*/
#ifndef LEPTONICA_IMAGEIO_H
#define LEPTONICA_IMAGEIO_H
/* ------------------ Image file format types -------------- */
/*
* The IFF_DEFAULT flag is used to write the file out in the
* same (input) file format that the pix was read from. If the pix
* was not read from file, the input format field will be
* IFF_UNKNOWN and the output file format will be chosen to
* be compressed and lossless; namely, IFF_TIFF_G4 for d = 1
* and IFF_PNG for everything else. IFF_JP2 is for jpeg2000, which
* is not supported in leptonica.
*
* In the future, new format types that have defined extensions
* will be added before IFF_DEFAULT, and will be kept in sync with
* the file format extensions in writefile.c. The positions of
* file formats before IFF_DEFAULT will remain invariant.
*/
enum {
IFF_UNKNOWN = 0,
IFF_BMP = 1,
IFF_JFIF_JPEG = 2,
IFF_PNG = 3,
IFF_TIFF = 4,
IFF_TIFF_PACKBITS = 5,
IFF_TIFF_RLE = 6,
IFF_TIFF_G3 = 7,
IFF_TIFF_G4 = 8,
IFF_TIFF_LZW = 9,
IFF_TIFF_ZIP = 10,
IFF_PNM = 11,
IFF_PS = 12,
IFF_GIF = 13,
IFF_JP2 = 14,
IFF_WEBP = 15,
IFF_LPDF = 16,
IFF_DEFAULT = 17,
IFF_SPIX = 18
};
/* ---------------------- Format header ids --------------------- */
enum {
BMP_ID = 0x4d42,
TIFF_BIGEND_ID = 0x4d4d, /* MM - for 'motorola' */
TIFF_LITTLEEND_ID = 0x4949 /* II - for 'intel' */
};
/* ------------- Hinting bit flags in jpeg reader --------------- */
enum {
L_JPEG_READ_LUMINANCE = 1, /* only want luminance data; no chroma */
L_JPEG_FAIL_ON_BAD_DATA = 2 /* don't return possibly damaged pix */
};
/* ------------------ Pdf formated encoding types --------------- */
enum {
L_JPEG_ENCODE = 1, /* use dct encoding: 8 and 32 bpp, no cmap */
L_G4_ENCODE = 2, /* use ccitt g4 fax encoding: 1 bpp */
L_FLATE_ENCODE = 3, /* use flate encoding: any depth, cmap ok */
L_JP2K_ENCODE = 4 /* use jp2k encoding: 8 and 32 bpp, no cmap */
};
/* ------------------ Compressed image data --------------------- */
/*
* In use, either datacomp or data85 will be produced, depending
* on whether the data needs to be ascii85 encoded. PostScript
* requires ascii85 encoding; pdf does not.
*
* For the colormap (flate compression only), PostScript uses ascii85
* encoding and pdf uses a bracketed array of space-separated
* hex-encoded rgb triples. Only tiff g4 (type == L_G4_ENCODE) uses
* the minisblack field.
*/
struct L_Compressed_Data
{
l_int32 type; /* encoding type: L_JPEG_ENCODE, etc */
l_uint8 *datacomp; /* gzipped raster data */
size_t nbytescomp; /* number of compressed bytes */
char *data85; /* ascii85-encoded gzipped raster data */
size_t nbytes85; /* number of ascii85 encoded bytes */
char *cmapdata85; /* ascii85-encoded uncompressed cmap */
char *cmapdatahex; /* hex pdf array for the cmap */
l_int32 ncolors; /* number of colors in cmap */
l_int32 w; /* image width */
l_int32 h; /* image height */
l_int32 bps; /* bits/sample; typ. 1, 2, 4 or 8 */
l_int32 spp; /* samples/pixel; typ. 1 or 3 */
l_int32 minisblack; /* tiff g4 photometry */
l_int32 predictor; /* flate data has PNG predictors */
size_t nbytes; /* number of uncompressed raster bytes */
l_int32 res; /* resolution (ppi) */
};
typedef struct L_Compressed_Data L_COMP_DATA;
/* ------------------------ Pdf multi-image flags ------------------------ */
enum {
L_FIRST_IMAGE = 1, /* first image to be used */
L_NEXT_IMAGE = 2, /* intermediate image; not first or last */
L_LAST_IMAGE = 3 /* last image to be used */
};
/* ------------------ Intermediate pdf generation data -------------------- */
/*
* This accumulates data for generating a pdf of a single page consisting
* of an arbitrary number of images.
*
* None of the strings have a trailing newline.
*/
struct L_Pdf_Data
{
char *title; /* optional title for pdf */
l_int32 n; /* number of images */
l_int32 ncmap; /* number of colormaps */
struct L_Ptra *cida; /* array of compressed image data */
char *id; /* %PDF-1.2 id string */
char *obj1; /* catalog string */
char *obj2; /* metadata string */
char *obj3; /* pages string */
char *obj4; /* page string (variable data) */
char *obj5; /* content string (variable data) */
char *poststream; /* post-binary-stream string */
char *trailer; /* trailer string (variable data) */
struct Pta *xy; /* store (xpt, ypt) array */
struct Pta *wh; /* store (wpt, hpt) array */
struct Box *mediabox; /* bounding region for all images */
struct Sarray *saprex; /* pre-binary-stream xobject strings */
struct Sarray *sacmap; /* colormap pdf object strings */
struct L_Dna *objsize; /* sizes of each pdf string object */
struct L_Dna *objloc; /* location of each pdf string object */
l_int32 xrefloc; /* location of xref */
};
typedef struct L_Pdf_Data L_PDF_DATA;
#endif /* LEPTONICA_IMAGEIO_H */