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[reactos.git] / reactos / dll / 3rdparty / libpng / pnginfo.h
1
2 /* pnginfo.h - header file for PNG reference library
3 *
4 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
5 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
6 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
7 *
8 * Last changed in libpng 1.5.0 [January 6, 2011]
9 *
10 * This code is released under the libpng license.
11 * For conditions of distribution and use, see the disclaimer
12 * and license in png.h
13 */
14
15 /* png_info is a structure that holds the information in a PNG file so
16 * that the application can find out the characteristics of the image.
17 * If you are reading the file, this structure will tell you what is
18 * in the PNG file. If you are writing the file, fill in the information
19 * you want to put into the PNG file, using png_set_*() functions, then
20 * call png_write_info().
21 *
22 * The names chosen should be very close to the PNG specification, so
23 * consult that document for information about the meaning of each field.
24 *
25 * With libpng < 0.95, it was only possible to directly set and read the
26 * the values in the png_info_struct, which meant that the contents and
27 * order of the values had to remain fixed. With libpng 0.95 and later,
28 * however, there are now functions that abstract the contents of
29 * png_info_struct from the application, so this makes it easier to use
30 * libpng with dynamic libraries, and even makes it possible to use
31 * libraries that don't have all of the libpng ancillary chunk-handing
32 * functionality. In libpng-1.5.0 this was moved into a separate private
33 * file that is not visible to applications.
34 *
35 * The following members may have allocated storage attached that should be
36 * cleaned up before the structure is discarded: palette, trans, text,
37 * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
38 * splt_palettes, scal_unit, row_pointers, and unknowns. By default, these
39 * are automatically freed when the info structure is deallocated, if they were
40 * allocated internally by libpng. This behavior can be changed by means
41 * of the png_data_freer() function.
42 *
43 * More allocation details: all the chunk-reading functions that
44 * change these members go through the corresponding png_set_*
45 * functions. A function to clear these members is available: see
46 * png_free_data(). The png_set_* functions do not depend on being
47 * able to point info structure members to any of the storage they are
48 * passed (they make their own copies), EXCEPT that the png_set_text
49 * functions use the same storage passed to them in the text_ptr or
50 * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
51 * functions do not make their own copies.
52 */
53 #ifndef PNGINFO_H
54 #define PNGINFO_H
55
56 struct png_info_def
57 {
58 /* the following are necessary for every PNG file */
59 png_uint_32 width; /* width of image in pixels (from IHDR) */
60 png_uint_32 height; /* height of image in pixels (from IHDR) */
61 png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */
62 png_size_t rowbytes; /* bytes needed to hold an untransformed row */
63 png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */
64 png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
65 png_uint_16 num_trans; /* number of transparent palette color (tRNS) */
66 png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
67 png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */
68 /* The following three should have been named *_method not *_type */
69 png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
70 png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
71 png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
72
73 /* The following is informational only on read, and not used on writes. */
74 png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */
75 png_byte pixel_depth; /* number of bits per pixel */
76 png_byte spare_byte; /* to align the data, and for future use */
77 png_byte signature[8]; /* magic bytes read by libpng from start of file */
78
79 /* The rest of the data is optional. If you are reading, check the
80 * valid field to see if the information in these are valid. If you
81 * are writing, set the valid field to those chunks you want written,
82 * and initialize the appropriate fields below.
83 */
84
85 #if defined(PNG_gAMA_SUPPORTED)
86 /* The gAMA chunk describes the gamma characteristics of the system
87 * on which the image was created, normally in the range [1.0, 2.5].
88 * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
89 */
90 png_fixed_point gamma;
91 #endif
92
93 #ifdef PNG_sRGB_SUPPORTED
94 /* GR-P, 0.96a */
95 /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
96 png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */
97 #endif
98
99 #ifdef PNG_TEXT_SUPPORTED
100 /* The tEXt, and zTXt chunks contain human-readable textual data in
101 * uncompressed, compressed, and optionally compressed forms, respectively.
102 * The data in "text" is an array of pointers to uncompressed,
103 * null-terminated C strings. Each chunk has a keyword that describes the
104 * textual data contained in that chunk. Keywords are not required to be
105 * unique, and the text string may be empty. Any number of text chunks may
106 * be in an image.
107 */
108 int num_text; /* number of comments read or comments to write */
109 int max_text; /* current size of text array */
110 png_textp text; /* array of comments read or comments to write */
111 #endif /* PNG_TEXT_SUPPORTED */
112
113 #ifdef PNG_tIME_SUPPORTED
114 /* The tIME chunk holds the last time the displayed image data was
115 * modified. See the png_time struct for the contents of this struct.
116 */
117 png_time mod_time;
118 #endif
119
120 #ifdef PNG_sBIT_SUPPORTED
121 /* The sBIT chunk specifies the number of significant high-order bits
122 * in the pixel data. Values are in the range [1, bit_depth], and are
123 * only specified for the channels in the pixel data. The contents of
124 * the low-order bits is not specified. Data is valid if
125 * (valid & PNG_INFO_sBIT) is non-zero.
126 */
127 png_color_8 sig_bit; /* significant bits in color channels */
128 #endif
129
130 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
131 defined(PNG_READ_BACKGROUND_SUPPORTED)
132 /* The tRNS chunk supplies transparency data for paletted images and
133 * other image types that don't need a full alpha channel. There are
134 * "num_trans" transparency values for a paletted image, stored in the
135 * same order as the palette colors, starting from index 0. Values
136 * for the data are in the range [0, 255], ranging from fully transparent
137 * to fully opaque, respectively. For non-paletted images, there is a
138 * single color specified that should be treated as fully transparent.
139 * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
140 */
141 png_bytep trans_alpha; /* alpha values for paletted image */
142 png_color_16 trans_color; /* transparent color for non-palette image */
143 #endif
144
145 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
146 /* The bKGD chunk gives the suggested image background color if the
147 * display program does not have its own background color and the image
148 * is needs to composited onto a background before display. The colors
149 * in "background" are normally in the same color space/depth as the
150 * pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
151 */
152 png_color_16 background;
153 #endif
154
155 #ifdef PNG_oFFs_SUPPORTED
156 /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
157 * and downwards from the top-left corner of the display, page, or other
158 * application-specific co-ordinate space. See the PNG_OFFSET_ defines
159 * below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero.
160 */
161 png_int_32 x_offset; /* x offset on page */
162 png_int_32 y_offset; /* y offset on page */
163 png_byte offset_unit_type; /* offset units type */
164 #endif
165
166 #ifdef PNG_pHYs_SUPPORTED
167 /* The pHYs chunk gives the physical pixel density of the image for
168 * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
169 * defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
170 */
171 png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
172 png_uint_32 y_pixels_per_unit; /* vertical pixel density */
173 png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
174 #endif
175
176 #ifdef PNG_hIST_SUPPORTED
177 /* The hIST chunk contains the relative frequency or importance of the
178 * various palette entries, so that a viewer can intelligently select a
179 * reduced-color palette, if required. Data is an array of "num_palette"
180 * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
181 * is non-zero.
182 */
183 png_uint_16p hist;
184 #endif
185
186 #ifdef PNG_cHRM_SUPPORTED
187 /* The cHRM chunk describes the CIE color characteristics of the monitor
188 * on which the PNG was created. This data allows the viewer to do gamut
189 * mapping of the input image to ensure that the viewer sees the same
190 * colors in the image as the creator. Values are in the range
191 * [0.0, 0.8]. Data valid if (valid & PNG_INFO_cHRM) non-zero.
192 */
193 png_fixed_point x_white;
194 png_fixed_point y_white;
195 png_fixed_point x_red;
196 png_fixed_point y_red;
197 png_fixed_point x_green;
198 png_fixed_point y_green;
199 png_fixed_point x_blue;
200 png_fixed_point y_blue;
201 #endif
202
203 #ifdef PNG_pCAL_SUPPORTED
204 /* The pCAL chunk describes a transformation between the stored pixel
205 * values and original physical data values used to create the image.
206 * The integer range [0, 2^bit_depth - 1] maps to the floating-point
207 * range given by [pcal_X0, pcal_X1], and are further transformed by a
208 * (possibly non-linear) transformation function given by "pcal_type"
209 * and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_
210 * defines below, and the PNG-Group's PNG extensions document for a
211 * complete description of the transformations and how they should be
212 * implemented, and for a description of the ASCII parameter strings.
213 * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
214 */
215 png_charp pcal_purpose; /* pCAL chunk description string */
216 png_int_32 pcal_X0; /* minimum value */
217 png_int_32 pcal_X1; /* maximum value */
218 png_charp pcal_units; /* Latin-1 string giving physical units */
219 png_charpp pcal_params; /* ASCII strings containing parameter values */
220 png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */
221 png_byte pcal_nparams; /* number of parameters given in pcal_params */
222 #endif
223
224 /* New members added in libpng-1.0.6 */
225 png_uint_32 free_me; /* flags items libpng is responsible for freeing */
226
227 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
228 defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
229 /* Storage for unknown chunks that the library doesn't recognize. */
230 png_unknown_chunkp unknown_chunks;
231 int unknown_chunks_num;
232 #endif
233
234 #ifdef PNG_iCCP_SUPPORTED
235 /* iCCP chunk data. */
236 png_charp iccp_name; /* profile name */
237 png_bytep iccp_profile; /* International Color Consortium profile data */
238 png_uint_32 iccp_proflen; /* ICC profile data length */
239 png_byte iccp_compression; /* Always zero */
240 #endif
241
242 #ifdef PNG_sPLT_SUPPORTED
243 /* Data on sPLT chunks (there may be more than one). */
244 png_sPLT_tp splt_palettes;
245 int splt_palettes_num;
246 #endif
247
248 #ifdef PNG_sCAL_SUPPORTED
249 /* The sCAL chunk describes the actual physical dimensions of the
250 * subject matter of the graphic. The chunk contains a unit specification
251 * a byte value, and two ASCII strings representing floating-point
252 * values. The values are width and height corresponsing to one pixel
253 * in the image. Data values are valid if (valid & PNG_INFO_sCAL) is
254 * non-zero.
255 */
256 png_byte scal_unit; /* unit of physical scale */
257 png_charp scal_s_width; /* string containing height */
258 png_charp scal_s_height; /* string containing width */
259 #endif
260
261 #ifdef PNG_INFO_IMAGE_SUPPORTED
262 /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
263 non-zero */
264 /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
265 png_bytepp row_pointers; /* the image bits */
266 #endif
267
268 };
269 #endif /* PNGINFO_H */