1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pnginfo.h - header file for PNG reference library
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Copyright (c) 2018 Cosmin Truta
33 * Copyright (c) 1998-2002,2004,2006-2013,2018 Glenn Randers-Pehrson
34 * Copyright (c) 1996-1997 Andreas Dilger
35 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 */
41
42 /* png_info is a structure that holds the information in a PNG file so
43 * that the application can find out the characteristics of the image.
44 * If you are reading the file, this structure will tell you what is
45 * in the PNG file. If you are writing the file, fill in the information
46 * you want to put into the PNG file, using png_set_*() functions, then
47 * call png_write_info().
48 *
49 * The names chosen should be very close to the PNG specification, so
50 * consult that document for information about the meaning of each field.
51 *
52 * With libpng < 0.95, it was only possible to directly set and read the
53 * the values in the png_info_struct, which meant that the contents and
54 * order of the values had to remain fixed. With libpng 0.95 and later,
55 * however, there are now functions that abstract the contents of
56 * png_info_struct from the application, so this makes it easier to use
57 * libpng with dynamic libraries, and even makes it possible to use
58 * libraries that don't have all of the libpng ancillary chunk-handing
59 * functionality. In libpng-1.5.0 this was moved into a separate private
60 * file that is not visible to applications.
61 *
62 * The following members may have allocated storage attached that should be
63 * cleaned up before the structure is discarded: palette, trans, text,
64 * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
65 * splt_palettes, scal_unit, row_pointers, and unknowns. By default, these
66 * are automatically freed when the info structure is deallocated, if they were
67 * allocated internally by libpng. This behavior can be changed by means
68 * of the png_data_freer() function.
69 *
70 * More allocation details: all the chunk-reading functions that
71 * change these members go through the corresponding png_set_*
72 * functions. A function to clear these members is available: see
73 * png_free_data(). The png_set_* functions do not depend on being
74 * able to point info structure members to any of the storage they are
75 * passed (they make their own copies), EXCEPT that the png_set_text
76 * functions use the same storage passed to them in the text_ptr or
77 * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
78 * functions do not make their own copies.
79 */
80 #ifndef PNGINFO_H
81 #define PNGINFO_H
82
83 struct png_info_def
84 {
85 /* The following are necessary for every PNG file */
86 png_uint_32 width; /* width of image in pixels (from IHDR) */
87 png_uint_32 height; /* height of image in pixels (from IHDR) */
88 png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */
89 size_t rowbytes; /* bytes needed to hold an untransformed row */
90 png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */
91 png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
92 png_uint_16 num_trans; /* number of transparent palette color (tRNS) */
93 png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
94 png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */
95 /* The following three should have been named *_method not *_type */
96 png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
97 png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
98 png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
99
100 /* The following are set by png_set_IHDR, called from the application on
101 * write, but the are never actually used by the write code.
102 */
103 png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */
104 png_byte pixel_depth; /* number of bits per pixel */
105 png_byte spare_byte; /* to align the data, and for future use */
106
107 #ifdef PNG_READ_SUPPORTED
108 /* This is never set during write */
109 png_byte signature[8]; /* magic bytes read by libpng from start of file */
110 #endif
111
112 /* The rest of the data is optional. If you are reading, check the
113 * valid field to see if the information in these are valid. If you
114 * are writing, set the valid field to those chunks you want written,
115 * and initialize the appropriate fields below.
116 */
117
118 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
119 /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are
120 * defined. When COLORSPACE is switched on all the colorspace-defining
121 * chunks should be enabled, when GAMMA is switched on all the gamma-defining
122 * chunks should be enabled. If this is not done it becomes possible to read
123 * inconsistent PNG files and assign a probably incorrect interpretation to
124 * the information. (In other words, by carefully choosing which chunks to
125 * recognize the system configuration can select an interpretation for PNG
126 * files containing ambiguous data and this will result in inconsistent
127 * behavior between different libpng builds!)
128 */
129 png_colorspace colorspace;
130 #endif
131
132 #ifdef PNG_iCCP_SUPPORTED
133 /* iCCP chunk data. */
134 png_charp iccp_name; /* profile name */
135 png_bytep iccp_profile; /* International Color Consortium profile data */
136 png_uint_32 iccp_proflen; /* ICC profile data length */
137 #endif
138
139 #ifdef PNG_TEXT_SUPPORTED
140 /* The tEXt, and zTXt chunks contain human-readable textual data in
141 * uncompressed, compressed, and optionally compressed forms, respectively.
142 * The data in "text" is an array of pointers to uncompressed,
143 * null-terminated C strings. Each chunk has a keyword that describes the
144 * textual data contained in that chunk. Keywords are not required to be
145 * unique, and the text string may be empty. Any number of text chunks may
146 * be in an image.
147 */
148 int num_text; /* number of comments read or comments to write */
149 int max_text; /* current size of text array */
150 png_textp text; /* array of comments read or comments to write */
151 #endif /* TEXT */
152
153 #ifdef PNG_tIME_SUPPORTED
154 /* The tIME chunk holds the last time the displayed image data was
155 * modified. See the png_time struct for the contents of this struct.
156 */
157 png_time mod_time;
158 #endif
159
160 #ifdef PNG_sBIT_SUPPORTED
161 /* The sBIT chunk specifies the number of significant high-order bits
162 * in the pixel data. Values are in the range [1, bit_depth], and are
163 * only specified for the channels in the pixel data. The contents of
164 * the low-order bits is not specified. Data is valid if
165 * (valid & PNG_INFO_sBIT) is non-zero.
166 */
167 png_color_8 sig_bit; /* significant bits in color channels */
168 #endif
169
170 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
171 defined(PNG_READ_BACKGROUND_SUPPORTED)
172 /* The tRNS chunk supplies transparency data for paletted images and
173 * other image types that don't need a full alpha channel. There are
174 * "num_trans" transparency values for a paletted image, stored in the
175 * same order as the palette colors, starting from index 0. Values
176 * for the data are in the range [0, 255], ranging from fully transparent
177 * to fully opaque, respectively. For non-paletted images, there is a
178 * single color specified that should be treated as fully transparent.
179 * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
180 */
181 png_bytep trans_alpha; /* alpha values for paletted image */
182 png_color_16 trans_color; /* transparent color for non-palette image */
183 #endif
184
185 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
186 /* The bKGD chunk gives the suggested image background color if the
187 * display program does not have its own background color and the image
188 * is needs to composited onto a background before display. The colors
189 * in "background" are normally in the same color space/depth as the
190 * pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
191 */
192 png_color_16 background;
193 #endif
194
195 #ifdef PNG_oFFs_SUPPORTED
196 /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
197 * and downwards from the top-left corner of the display, page, or other
198 * application-specific co-ordinate space. See the PNG_OFFSET_ defines
199 * below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero.
200 */
201 png_int_32 x_offset; /* x offset on page */
202 png_int_32 y_offset; /* y offset on page */
203 png_byte offset_unit_type; /* offset units type */
204 #endif
205
206 #ifdef PNG_pHYs_SUPPORTED
207 /* The pHYs chunk gives the physical pixel density of the image for
208 * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
209 * defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
210 */
211 png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
212 png_uint_32 y_pixels_per_unit; /* vertical pixel density */
213 png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
214 #endif
215
216 #ifdef PNG_eXIf_SUPPORTED
217 int num_exif; /* Added at libpng-1.6.31 */
218 png_bytep exif;
219 # ifdef PNG_READ_eXIf_SUPPORTED
220 png_bytep eXIf_buf; /* Added at libpng-1.6.32 */
221 # endif
222 #endif
223
224 #ifdef PNG_hIST_SUPPORTED
225 /* The hIST chunk contains the relative frequency or importance of the
226 * various palette entries, so that a viewer can intelligently select a
227 * reduced-color palette, if required. Data is an array of "num_palette"
228 * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
229 * is non-zero.
230 */
231 png_uint_16p hist;
232 #endif
233
234 #ifdef PNG_pCAL_SUPPORTED
235 /* The pCAL chunk describes a transformation between the stored pixel
236 * values and original physical data values used to create the image.
237 * The integer range [0, 2^bit_depth - 1] maps to the floating-point
238 * range given by [pcal_X0, pcal_X1], and are further transformed by a
239 * (possibly non-linear) transformation function given by "pcal_type"
240 * and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_
241 * defines below, and the PNG-Group's PNG extensions document for a
242 * complete description of the transformations and how they should be
243 * implemented, and for a description of the ASCII parameter strings.
244 * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
245 */
246 png_charp pcal_purpose; /* pCAL chunk description string */
247 png_int_32 pcal_X0; /* minimum value */
248 png_int_32 pcal_X1; /* maximum value */
249 png_charp pcal_units; /* Latin-1 string giving physical units */
250 png_charpp pcal_params; /* ASCII strings containing parameter values */
251 png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */
252 png_byte pcal_nparams; /* number of parameters given in pcal_params */
253 #endif
254
255 /* New members added in libpng-1.0.6 */
256 png_uint_32 free_me; /* flags items libpng is responsible for freeing */
257
258 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
259 /* Storage for unknown chunks that the library doesn't recognize. */
260 png_unknown_chunkp unknown_chunks;
261
262 /* The type of this field is limited by the type of
263 * png_struct::user_chunk_cache_max, else overflow can occur.
264 */
265 int unknown_chunks_num;
266 #endif
267
268 #ifdef PNG_sPLT_SUPPORTED
269 /* Data on sPLT chunks (there may be more than one). */
270 png_sPLT_tp splt_palettes;
271 int splt_palettes_num; /* Match type returned by png_get API */
272 #endif
273
274 #ifdef PNG_sCAL_SUPPORTED
275 /* The sCAL chunk describes the actual physical dimensions of the
276 * subject matter of the graphic. The chunk contains a unit specification
277 * a byte value, and two ASCII strings representing floating-point
278 * values. The values are width and height corresponding to one pixel
279 * in the image. Data values are valid if (valid & PNG_INFO_sCAL) is
280 * non-zero.
281 */
282 png_byte scal_unit; /* unit of physical scale */
283 png_charp scal_s_width; /* string containing height */
284 png_charp scal_s_height; /* string containing width */
285 #endif
286
287 #ifdef PNG_INFO_IMAGE_SUPPORTED
288 /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
289 non-zero */
290 /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
291 png_bytepp row_pointers; /* the image bits */
292 #endif
293
294 };
295 #endif /* PNGINFO_H */