imageio.h 9.1 KB

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  1. /*====================================================================*
  2. - Copyright (C) 2001 Leptonica. All rights reserved.
  3. -
  4. - Redistribution and use in source and binary forms, with or without
  5. - modification, are permitted provided that the following conditions
  6. - are met:
  7. - 1. Redistributions of source code must retain the above copyright
  8. - notice, this list of conditions and the following disclaimer.
  9. - 2. Redistributions in binary form must reproduce the above
  10. - copyright notice, this list of conditions and the following
  11. - disclaimer in the documentation and/or other materials
  12. - provided with the distribution.
  13. -
  14. - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  15. - ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  16. - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  17. - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
  18. - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19. - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20. - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  21. - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  22. - OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  23. - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  24. - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25. *====================================================================*/
  26. /*
  27. * General features of image I/O in leptonica
  28. *
  29. * At present, there are 9 file formats for images that can be read
  30. * and written:
  31. * png (requires libpng, libz)
  32. * jpeg (requires libjpeg)
  33. * tiff (requires libtiff, libz)
  34. * gif (requires libgif)
  35. * webp (requires libwebp)
  36. * jp2 (requires libopenjp2)
  37. * bmp (no library required)
  38. * pnm (no library required)
  39. * spix (no library required)
  40. * Additionally, there are two file formats for writing (only) images:
  41. * PostScript (requires libpng, libz, libjpeg, libtiff)
  42. * pdf (requires libpng, libz, libjpeg, libtiff)
  43. *
  44. * For all 9 read/write formats, leptonica provides interconversion
  45. * between pix (with raster data) and formatted image data:
  46. * Conversion from pix (typically compression):
  47. * pixWrite(): pix --> file
  48. * pixWriteStream(): pix --> filestream (aka FILE*)
  49. * pixWriteMem(): pix --> memory buffer
  50. * Conversion to pix (typically decompression):
  51. * pixRead(): file --> pix
  52. * pixReadStream(): filestream --> pix
  53. * pixReadMem(): memory buffer --> pix
  54. *
  55. * Conversions for which the image data is not compressed are:
  56. * * uncompressed tiff (IFF_TIFF)
  57. * * bmp
  58. * * pnm
  59. * * spix (fast serialization that copies the pix raster data)
  60. *
  61. * The image header (metadata) information can be read from either
  62. * the compressed file or a memory buffer, for all 9 formats.
  63. */
  64. #ifndef LEPTONICA_IMAGEIO_H
  65. #define LEPTONICA_IMAGEIO_H
  66. /* ------------------ Image file format types -------------- */
  67. /*
  68. * The IFF_DEFAULT flag is used to write the file out in the
  69. * same (input) file format that the pix was read from. If the pix
  70. * was not read from file, the input format field will be
  71. * IFF_UNKNOWN and the output file format will be chosen to
  72. * be compressed and lossless; namely, IFF_TIFF_G4 for d = 1
  73. * and IFF_PNG for everything else. IFF_JP2 is for jpeg2000, which
  74. * is not supported in leptonica.
  75. *
  76. * In the future, new format types that have defined extensions
  77. * will be added before IFF_DEFAULT, and will be kept in sync with
  78. * the file format extensions in writefile.c. The positions of
  79. * file formats before IFF_DEFAULT will remain invariant.
  80. */
  81. enum {
  82. IFF_UNKNOWN = 0,
  83. IFF_BMP = 1,
  84. IFF_JFIF_JPEG = 2,
  85. IFF_PNG = 3,
  86. IFF_TIFF = 4,
  87. IFF_TIFF_PACKBITS = 5,
  88. IFF_TIFF_RLE = 6,
  89. IFF_TIFF_G3 = 7,
  90. IFF_TIFF_G4 = 8,
  91. IFF_TIFF_LZW = 9,
  92. IFF_TIFF_ZIP = 10,
  93. IFF_PNM = 11,
  94. IFF_PS = 12,
  95. IFF_GIF = 13,
  96. IFF_JP2 = 14,
  97. IFF_WEBP = 15,
  98. IFF_LPDF = 16,
  99. IFF_DEFAULT = 17,
  100. IFF_SPIX = 18
  101. };
  102. /* ---------------------- Format header ids --------------------- */
  103. enum {
  104. BMP_ID = 0x4d42,
  105. TIFF_BIGEND_ID = 0x4d4d, /* MM - for 'motorola' */
  106. TIFF_LITTLEEND_ID = 0x4949 /* II - for 'intel' */
  107. };
  108. /* ------------- Hinting bit flags in jpeg reader --------------- */
  109. enum {
  110. L_JPEG_READ_LUMINANCE = 1, /* only want luminance data; no chroma */
  111. L_JPEG_FAIL_ON_BAD_DATA = 2 /* don't return possibly damaged pix */
  112. };
  113. /* ------------------ Pdf formated encoding types --------------- */
  114. enum {
  115. L_JPEG_ENCODE = 1, /* use dct encoding: 8 and 32 bpp, no cmap */
  116. L_G4_ENCODE = 2, /* use ccitt g4 fax encoding: 1 bpp */
  117. L_FLATE_ENCODE = 3, /* use flate encoding: any depth, cmap ok */
  118. L_JP2K_ENCODE = 4 /* use jp2k encoding: 8 and 32 bpp, no cmap */
  119. };
  120. /* ------------------ Compressed image data --------------------- */
  121. /*
  122. * In use, either datacomp or data85 will be produced, depending
  123. * on whether the data needs to be ascii85 encoded. PostScript
  124. * requires ascii85 encoding; pdf does not.
  125. *
  126. * For the colormap (flate compression only), PostScript uses ascii85
  127. * encoding and pdf uses a bracketed array of space-separated
  128. * hex-encoded rgb triples. Only tiff g4 (type == L_G4_ENCODE) uses
  129. * the minisblack field.
  130. */
  131. struct L_Compressed_Data
  132. {
  133. l_int32 type; /* encoding type: L_JPEG_ENCODE, etc */
  134. l_uint8 *datacomp; /* gzipped raster data */
  135. size_t nbytescomp; /* number of compressed bytes */
  136. char *data85; /* ascii85-encoded gzipped raster data */
  137. size_t nbytes85; /* number of ascii85 encoded bytes */
  138. char *cmapdata85; /* ascii85-encoded uncompressed cmap */
  139. char *cmapdatahex; /* hex pdf array for the cmap */
  140. l_int32 ncolors; /* number of colors in cmap */
  141. l_int32 w; /* image width */
  142. l_int32 h; /* image height */
  143. l_int32 bps; /* bits/sample; typ. 1, 2, 4 or 8 */
  144. l_int32 spp; /* samples/pixel; typ. 1 or 3 */
  145. l_int32 minisblack; /* tiff g4 photometry */
  146. l_int32 predictor; /* flate data has PNG predictors */
  147. size_t nbytes; /* number of uncompressed raster bytes */
  148. l_int32 res; /* resolution (ppi) */
  149. };
  150. typedef struct L_Compressed_Data L_COMP_DATA;
  151. /* ------------------------ Pdf multi-image flags ------------------------ */
  152. enum {
  153. L_FIRST_IMAGE = 1, /* first image to be used */
  154. L_NEXT_IMAGE = 2, /* intermediate image; not first or last */
  155. L_LAST_IMAGE = 3 /* last image to be used */
  156. };
  157. /* ------------------ Intermediate pdf generation data -------------------- */
  158. /*
  159. * This accumulates data for generating a pdf of a single page consisting
  160. * of an arbitrary number of images.
  161. *
  162. * None of the strings have a trailing newline.
  163. */
  164. struct L_Pdf_Data
  165. {
  166. char *title; /* optional title for pdf */
  167. l_int32 n; /* number of images */
  168. l_int32 ncmap; /* number of colormaps */
  169. struct L_Ptra *cida; /* array of compressed image data */
  170. char *id; /* %PDF-1.2 id string */
  171. char *obj1; /* catalog string */
  172. char *obj2; /* metadata string */
  173. char *obj3; /* pages string */
  174. char *obj4; /* page string (variable data) */
  175. char *obj5; /* content string (variable data) */
  176. char *poststream; /* post-binary-stream string */
  177. char *trailer; /* trailer string (variable data) */
  178. struct Pta *xy; /* store (xpt, ypt) array */
  179. struct Pta *wh; /* store (wpt, hpt) array */
  180. struct Box *mediabox; /* bounding region for all images */
  181. struct Sarray *saprex; /* pre-binary-stream xobject strings */
  182. struct Sarray *sacmap; /* colormap pdf object strings */
  183. struct L_Dna *objsize; /* sizes of each pdf string object */
  184. struct L_Dna *objloc; /* location of each pdf string object */
  185. l_int32 xrefloc; /* location of xref */
  186. };
  187. typedef struct L_Pdf_Data L_PDF_DATA;
  188. #endif /* LEPTONICA_IMAGEIO_H */