michael@0: michael@0: /* pnginfo.h - header file for PNG reference library michael@0: * michael@0: * Copyright (c) 1998-2013 Glenn Randers-Pehrson michael@0: * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) michael@0: * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) michael@0: * michael@0: * Last changed in libpng 1.6.1 [March 28, 2013] michael@0: * michael@0: * This code is released under the libpng license. michael@0: * For conditions of distribution and use, see the disclaimer michael@0: * and license in png.h michael@0: */ michael@0: michael@0: /* png_info is a structure that holds the information in a PNG file so michael@0: * that the application can find out the characteristics of the image. michael@0: * If you are reading the file, this structure will tell you what is michael@0: * in the PNG file. If you are writing the file, fill in the information michael@0: * you want to put into the PNG file, using png_set_*() functions, then michael@0: * call png_write_info(). michael@0: * michael@0: * The names chosen should be very close to the PNG specification, so michael@0: * consult that document for information about the meaning of each field. michael@0: * michael@0: * With libpng < 0.95, it was only possible to directly set and read the michael@0: * the values in the png_info_struct, which meant that the contents and michael@0: * order of the values had to remain fixed. With libpng 0.95 and later, michael@0: * however, there are now functions that abstract the contents of michael@0: * png_info_struct from the application, so this makes it easier to use michael@0: * libpng with dynamic libraries, and even makes it possible to use michael@0: * libraries that don't have all of the libpng ancillary chunk-handing michael@0: * functionality. In libpng-1.5.0 this was moved into a separate private michael@0: * file that is not visible to applications. michael@0: * michael@0: * The following members may have allocated storage attached that should be michael@0: * cleaned up before the structure is discarded: palette, trans, text, michael@0: * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile, michael@0: * splt_palettes, scal_unit, row_pointers, and unknowns. By default, these michael@0: * are automatically freed when the info structure is deallocated, if they were michael@0: * allocated internally by libpng. This behavior can be changed by means michael@0: * of the png_data_freer() function. michael@0: * michael@0: * More allocation details: all the chunk-reading functions that michael@0: * change these members go through the corresponding png_set_* michael@0: * functions. A function to clear these members is available: see michael@0: * png_free_data(). The png_set_* functions do not depend on being michael@0: * able to point info structure members to any of the storage they are michael@0: * passed (they make their own copies), EXCEPT that the png_set_text michael@0: * functions use the same storage passed to them in the text_ptr or michael@0: * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns michael@0: * functions do not make their own copies. michael@0: */ michael@0: #ifndef PNGINFO_H michael@0: #define PNGINFO_H michael@0: michael@0: struct png_info_def michael@0: { michael@0: /* The following are necessary for every PNG file */ michael@0: png_uint_32 width; /* width of image in pixels (from IHDR) */ michael@0: png_uint_32 height; /* height of image in pixels (from IHDR) */ michael@0: png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */ michael@0: png_size_t rowbytes; /* bytes needed to hold an untransformed row */ michael@0: png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */ michael@0: png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */ michael@0: png_uint_16 num_trans; /* number of transparent palette color (tRNS) */ michael@0: png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */ michael@0: png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */ michael@0: /* The following three should have been named *_method not *_type */ michael@0: png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */ michael@0: png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */ michael@0: png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */ michael@0: michael@0: /* The following are set by png_set_IHDR, called from the application on michael@0: * write, but the are never actually used by the write code. michael@0: */ michael@0: png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */ michael@0: png_byte pixel_depth; /* number of bits per pixel */ michael@0: png_byte spare_byte; /* to align the data, and for future use */ michael@0: michael@0: #ifdef PNG_READ_SUPPORTED michael@0: /* This is never set during write */ michael@0: png_byte signature[8]; /* magic bytes read by libpng from start of file */ michael@0: #endif michael@0: michael@0: /* The rest of the data is optional. If you are reading, check the michael@0: * valid field to see if the information in these are valid. If you michael@0: * are writing, set the valid field to those chunks you want written, michael@0: * and initialize the appropriate fields below. michael@0: */ michael@0: michael@0: #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED) michael@0: /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are michael@0: * defined. When COLORSPACE is switched on all the colorspace-defining michael@0: * chunks should be enabled, when GAMMA is switched on all the gamma-defining michael@0: * chunks should be enabled. If this is not done it becomes possible to read michael@0: * inconsistent PNG files and assign a probably incorrect interpretation to michael@0: * the information. (In other words, by carefully choosing which chunks to michael@0: * recognize the system configuration can select an interpretation for PNG michael@0: * files containing ambiguous data and this will result in inconsistent michael@0: * behavior between different libpng builds!) michael@0: */ michael@0: png_colorspace colorspace; michael@0: #endif michael@0: michael@0: #ifdef PNG_iCCP_SUPPORTED michael@0: /* iCCP chunk data. */ michael@0: png_charp iccp_name; /* profile name */ michael@0: png_bytep iccp_profile; /* International Color Consortium profile data */ michael@0: png_uint_32 iccp_proflen; /* ICC profile data length */ michael@0: #endif michael@0: michael@0: #ifdef PNG_TEXT_SUPPORTED michael@0: /* The tEXt, and zTXt chunks contain human-readable textual data in michael@0: * uncompressed, compressed, and optionally compressed forms, respectively. michael@0: * The data in "text" is an array of pointers to uncompressed, michael@0: * null-terminated C strings. Each chunk has a keyword that describes the michael@0: * textual data contained in that chunk. Keywords are not required to be michael@0: * unique, and the text string may be empty. Any number of text chunks may michael@0: * be in an image. michael@0: */ michael@0: int num_text; /* number of comments read or comments to write */ michael@0: int max_text; /* current size of text array */ michael@0: png_textp text; /* array of comments read or comments to write */ michael@0: #endif /* PNG_TEXT_SUPPORTED */ michael@0: michael@0: #ifdef PNG_tIME_SUPPORTED michael@0: /* The tIME chunk holds the last time the displayed image data was michael@0: * modified. See the png_time struct for the contents of this struct. michael@0: */ michael@0: png_time mod_time; michael@0: #endif michael@0: michael@0: #ifdef PNG_sBIT_SUPPORTED michael@0: /* The sBIT chunk specifies the number of significant high-order bits michael@0: * in the pixel data. Values are in the range [1, bit_depth], and are michael@0: * only specified for the channels in the pixel data. The contents of michael@0: * the low-order bits is not specified. Data is valid if michael@0: * (valid & PNG_INFO_sBIT) is non-zero. michael@0: */ michael@0: png_color_8 sig_bit; /* significant bits in color channels */ michael@0: #endif michael@0: michael@0: #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \ michael@0: defined(PNG_READ_BACKGROUND_SUPPORTED) michael@0: /* The tRNS chunk supplies transparency data for paletted images and michael@0: * other image types that don't need a full alpha channel. There are michael@0: * "num_trans" transparency values for a paletted image, stored in the michael@0: * same order as the palette colors, starting from index 0. Values michael@0: * for the data are in the range [0, 255], ranging from fully transparent michael@0: * to fully opaque, respectively. For non-paletted images, there is a michael@0: * single color specified that should be treated as fully transparent. michael@0: * Data is valid if (valid & PNG_INFO_tRNS) is non-zero. michael@0: */ michael@0: png_bytep trans_alpha; /* alpha values for paletted image */ michael@0: png_color_16 trans_color; /* transparent color for non-palette image */ michael@0: #endif michael@0: michael@0: #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) michael@0: /* The bKGD chunk gives the suggested image background color if the michael@0: * display program does not have its own background color and the image michael@0: * is needs to composited onto a background before display. The colors michael@0: * in "background" are normally in the same color space/depth as the michael@0: * pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero. michael@0: */ michael@0: png_color_16 background; michael@0: #endif michael@0: michael@0: #ifdef PNG_oFFs_SUPPORTED michael@0: /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards michael@0: * and downwards from the top-left corner of the display, page, or other michael@0: * application-specific co-ordinate space. See the PNG_OFFSET_ defines michael@0: * below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero. michael@0: */ michael@0: png_int_32 x_offset; /* x offset on page */ michael@0: png_int_32 y_offset; /* y offset on page */ michael@0: png_byte offset_unit_type; /* offset units type */ michael@0: #endif michael@0: michael@0: #ifdef PNG_pHYs_SUPPORTED michael@0: /* The pHYs chunk gives the physical pixel density of the image for michael@0: * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_ michael@0: * defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero. michael@0: */ michael@0: png_uint_32 x_pixels_per_unit; /* horizontal pixel density */ michael@0: png_uint_32 y_pixels_per_unit; /* vertical pixel density */ michael@0: png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */ michael@0: #endif michael@0: michael@0: #ifdef PNG_hIST_SUPPORTED michael@0: /* The hIST chunk contains the relative frequency or importance of the michael@0: * various palette entries, so that a viewer can intelligently select a michael@0: * reduced-color palette, if required. Data is an array of "num_palette" michael@0: * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST) michael@0: * is non-zero. michael@0: */ michael@0: png_uint_16p hist; michael@0: #endif michael@0: michael@0: #ifdef PNG_pCAL_SUPPORTED michael@0: /* The pCAL chunk describes a transformation between the stored pixel michael@0: * values and original physical data values used to create the image. michael@0: * The integer range [0, 2^bit_depth - 1] maps to the floating-point michael@0: * range given by [pcal_X0, pcal_X1], and are further transformed by a michael@0: * (possibly non-linear) transformation function given by "pcal_type" michael@0: * and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_ michael@0: * defines below, and the PNG-Group's PNG extensions document for a michael@0: * complete description of the transformations and how they should be michael@0: * implemented, and for a description of the ASCII parameter strings. michael@0: * Data values are valid if (valid & PNG_INFO_pCAL) non-zero. michael@0: */ michael@0: png_charp pcal_purpose; /* pCAL chunk description string */ michael@0: png_int_32 pcal_X0; /* minimum value */ michael@0: png_int_32 pcal_X1; /* maximum value */ michael@0: png_charp pcal_units; /* Latin-1 string giving physical units */ michael@0: png_charpp pcal_params; /* ASCII strings containing parameter values */ michael@0: png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */ michael@0: png_byte pcal_nparams; /* number of parameters given in pcal_params */ michael@0: #endif michael@0: michael@0: /* New members added in libpng-1.0.6 */ michael@0: png_uint_32 free_me; /* flags items libpng is responsible for freeing */ michael@0: michael@0: #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED michael@0: /* Storage for unknown chunks that the library doesn't recognize. */ michael@0: png_unknown_chunkp unknown_chunks; michael@0: michael@0: /* The type of this field is limited by the type of michael@0: * png_struct::user_chunk_cache_max, else overflow can occur. michael@0: */ michael@0: int unknown_chunks_num; michael@0: #endif michael@0: michael@0: #ifdef PNG_sPLT_SUPPORTED michael@0: /* Data on sPLT chunks (there may be more than one). */ michael@0: png_sPLT_tp splt_palettes; michael@0: int splt_palettes_num; /* Match type returned by png_get API */ michael@0: #endif michael@0: michael@0: #ifdef PNG_sCAL_SUPPORTED michael@0: /* The sCAL chunk describes the actual physical dimensions of the michael@0: * subject matter of the graphic. The chunk contains a unit specification michael@0: * a byte value, and two ASCII strings representing floating-point michael@0: * values. The values are width and height corresponsing to one pixel michael@0: * in the image. Data values are valid if (valid & PNG_INFO_sCAL) is michael@0: * non-zero. michael@0: */ michael@0: png_byte scal_unit; /* unit of physical scale */ michael@0: png_charp scal_s_width; /* string containing height */ michael@0: png_charp scal_s_height; /* string containing width */ michael@0: #endif michael@0: michael@0: #ifdef PNG_INFO_IMAGE_SUPPORTED michael@0: /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) michael@0: non-zero */ michael@0: /* Data valid if (valid & PNG_INFO_IDAT) non-zero */ michael@0: png_bytepp row_pointers; /* the image bits */ michael@0: #endif michael@0: michael@0: #ifdef PNG_APNG_SUPPORTED michael@0: png_uint_32 num_frames; /* including default image */ michael@0: png_uint_32 num_plays; michael@0: png_uint_32 next_frame_width; michael@0: png_uint_32 next_frame_height; michael@0: png_uint_32 next_frame_x_offset; michael@0: png_uint_32 next_frame_y_offset; michael@0: png_uint_16 next_frame_delay_num; michael@0: png_uint_16 next_frame_delay_den; michael@0: png_byte next_frame_dispose_op; michael@0: png_byte next_frame_blend_op; michael@0: #endif michael@0: michael@0: }; michael@0: #endif /* PNGINFO_H */