295 lines
13 KiB
C
295 lines
13 KiB
C
|
|
/* pnginfo.h - header file for PNG reference library
|
|
*
|
|
* Copyright (c) 1998-2010 Glenn Randers-Pehrson
|
|
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
|
|
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
|
|
*
|
|
* Last changed in libpng version 1.5.0 - June 29, 2010
|
|
*
|
|
* This code is released under the libpng license.
|
|
* For conditions of distribution and use, see the disclaimer
|
|
* and license in png.h
|
|
*/
|
|
|
|
/* png_info is a structure that holds the information in a PNG file so
|
|
* that the application can find out the characteristics of the image.
|
|
* If you are reading the file, this structure will tell you what is
|
|
* in the PNG file. If you are writing the file, fill in the information
|
|
* you want to put into the PNG file, using png_set_*() functions, then
|
|
* call png_write_info().
|
|
*
|
|
* The names chosen should be very close to the PNG specification, so
|
|
* consult that document for information about the meaning of each field.
|
|
*
|
|
* With libpng < 0.95, it was only possible to directly set and read the
|
|
* the values in the png_info_struct, which meant that the contents and
|
|
* order of the values had to remain fixed. With libpng 0.95 and later,
|
|
* however, there are now functions that abstract the contents of
|
|
* png_info_struct from the application, so this makes it easier to use
|
|
* libpng with dynamic libraries, and even makes it possible to use
|
|
* libraries that don't have all of the libpng ancillary chunk-handing
|
|
* functionality. In libpng-1.5.0 this was moved into a separate private
|
|
* file that is not visible to applications.
|
|
*
|
|
* The following members may have allocated storage attached that should be
|
|
* cleaned up before the structure is discarded: palette, trans, text,
|
|
* pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
|
|
* splt_palettes, scal_unit, row_pointers, and unknowns. By default, these
|
|
* are automatically freed when the info structure is deallocated, if they were
|
|
* allocated internally by libpng. This behavior can be changed by means
|
|
* of the png_data_freer() function.
|
|
*
|
|
* More allocation details: all the chunk-reading functions that
|
|
* change these members go through the corresponding png_set_*
|
|
* functions. A function to clear these members is available: see
|
|
* png_free_data(). The png_set_* functions do not depend on being
|
|
* able to point info structure members to any of the storage they are
|
|
* passed (they make their own copies), EXCEPT that the png_set_text
|
|
* functions use the same storage passed to them in the text_ptr or
|
|
* itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
|
|
* functions do not make their own copies.
|
|
*/
|
|
#ifndef PNGINFO_H
|
|
#define PNGINFO_H
|
|
|
|
struct png_info_def
|
|
{
|
|
/* the following are necessary for every PNG file */
|
|
png_uint_32 width; /* width of image in pixels (from IHDR) */
|
|
png_uint_32 height; /* height of image in pixels (from IHDR) */
|
|
png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */
|
|
png_size_t rowbytes; /* bytes needed to hold an untransformed row */
|
|
png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */
|
|
png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
|
|
png_uint_16 num_trans; /* number of transparent palette color (tRNS) */
|
|
png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
|
|
png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */
|
|
/* The following three should have been named *_method not *_type */
|
|
png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
|
|
png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
|
|
png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
|
|
|
|
/* The following is informational only on read, and not used on writes. */
|
|
png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */
|
|
png_byte pixel_depth; /* number of bits per pixel */
|
|
png_byte spare_byte; /* to align the data, and for future use */
|
|
png_byte signature[8]; /* magic bytes read by libpng from start of file */
|
|
|
|
/* The rest of the data is optional. If you are reading, check the
|
|
* valid field to see if the information in these are valid. If you
|
|
* are writing, set the valid field to those chunks you want written,
|
|
* and initialize the appropriate fields below.
|
|
*/
|
|
|
|
#if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
|
|
/* The gAMA chunk describes the gamma characteristics of the system
|
|
* on which the image was created, normally in the range [1.0, 2.5].
|
|
* Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
|
|
*/
|
|
float gamma; /* gamma value of image, if (valid & PNG_INFO_gAMA) */
|
|
#endif
|
|
|
|
#ifdef PNG_sRGB_SUPPORTED
|
|
/* GR-P, 0.96a */
|
|
/* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
|
|
png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */
|
|
#endif
|
|
|
|
#ifdef PNG_TEXT_SUPPORTED
|
|
/* The tEXt, and zTXt chunks contain human-readable textual data in
|
|
* uncompressed, compressed, and optionally compressed forms, respectively.
|
|
* The data in "text" is an array of pointers to uncompressed,
|
|
* null-terminated C strings. Each chunk has a keyword that describes the
|
|
* textual data contained in that chunk. Keywords are not required to be
|
|
* unique, and the text string may be empty. Any number of text chunks may
|
|
* be in an image.
|
|
*/
|
|
int num_text; /* number of comments read or comments to write */
|
|
int max_text; /* current size of text array */
|
|
png_textp text; /* array of comments read or comments to write */
|
|
#endif /* PNG_TEXT_SUPPORTED */
|
|
|
|
#ifdef PNG_tIME_SUPPORTED
|
|
/* The tIME chunk holds the last time the displayed image data was
|
|
* modified. See the png_time struct for the contents of this struct.
|
|
*/
|
|
png_time mod_time;
|
|
#endif
|
|
|
|
#ifdef PNG_sBIT_SUPPORTED
|
|
/* The sBIT chunk specifies the number of significant high-order bits
|
|
* in the pixel data. Values are in the range [1, bit_depth], and are
|
|
* only specified for the channels in the pixel data. The contents of
|
|
* the low-order bits is not specified. Data is valid if
|
|
* (valid & PNG_INFO_sBIT) is non-zero.
|
|
*/
|
|
png_color_8 sig_bit; /* significant bits in color channels */
|
|
#endif
|
|
|
|
#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
|
|
defined(PNG_READ_BACKGROUND_SUPPORTED)
|
|
/* The tRNS chunk supplies transparency data for paletted images and
|
|
* other image types that don't need a full alpha channel. There are
|
|
* "num_trans" transparency values for a paletted image, stored in the
|
|
* same order as the palette colors, starting from index 0. Values
|
|
* for the data are in the range [0, 255], ranging from fully transparent
|
|
* to fully opaque, respectively. For non-paletted images, there is a
|
|
* single color specified that should be treated as fully transparent.
|
|
* Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
|
|
*/
|
|
png_bytep trans; /* alpha values for paletted image */
|
|
png_bytep trans_alpha; /* alpha values for paletted image */
|
|
png_color_16 trans_color; /* transparent color for non-palette image */
|
|
#endif
|
|
|
|
#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
|
|
/* The bKGD chunk gives the suggested image background color if the
|
|
* display program does not have its own background color and the image
|
|
* is needs to composited onto a background before display. The colors
|
|
* in "background" are normally in the same color space/depth as the
|
|
* pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
|
|
*/
|
|
png_color_16 background;
|
|
#endif
|
|
|
|
#ifdef PNG_oFFs_SUPPORTED
|
|
/* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
|
|
* and downwards from the top-left corner of the display, page, or other
|
|
* application-specific co-ordinate space. See the PNG_OFFSET_ defines
|
|
* below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero.
|
|
*/
|
|
png_int_32 x_offset; /* x offset on page */
|
|
png_int_32 y_offset; /* y offset on page */
|
|
png_byte offset_unit_type; /* offset units type */
|
|
#endif
|
|
|
|
#ifdef PNG_pHYs_SUPPORTED
|
|
/* The pHYs chunk gives the physical pixel density of the image for
|
|
* display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
|
|
* defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
|
|
*/
|
|
png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
|
|
png_uint_32 y_pixels_per_unit; /* vertical pixel density */
|
|
png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
|
|
#endif
|
|
|
|
#ifdef PNG_hIST_SUPPORTED
|
|
/* The hIST chunk contains the relative frequency or importance of the
|
|
* various palette entries, so that a viewer can intelligently select a
|
|
* reduced-color palette, if required. Data is an array of "num_palette"
|
|
* values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
|
|
* is non-zero.
|
|
*/
|
|
png_uint_16p hist;
|
|
#endif
|
|
|
|
#ifdef PNG_cHRM_SUPPORTED
|
|
/* The cHRM chunk describes the CIE color characteristics of the monitor
|
|
* on which the PNG was created. This data allows the viewer to do gamut
|
|
* mapping of the input image to ensure that the viewer sees the same
|
|
* colors in the image as the creator. Values are in the range
|
|
* [0.0, 0.8]. Data valid if (valid & PNG_INFO_cHRM) non-zero.
|
|
*/
|
|
#ifdef PNG_FLOATING_POINT_SUPPORTED
|
|
float x_white;
|
|
float y_white;
|
|
float x_red;
|
|
float y_red;
|
|
float x_green;
|
|
float y_green;
|
|
float x_blue;
|
|
float y_blue;
|
|
#endif
|
|
#endif
|
|
|
|
#ifdef PNG_pCAL_SUPPORTED
|
|
/* The pCAL chunk describes a transformation between the stored pixel
|
|
* values and original physical data values used to create the image.
|
|
* The integer range [0, 2^bit_depth - 1] maps to the floating-point
|
|
* range given by [pcal_X0, pcal_X1], and are further transformed by a
|
|
* (possibly non-linear) transformation function given by "pcal_type"
|
|
* and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_
|
|
* defines below, and the PNG-Group's PNG extensions document for a
|
|
* complete description of the transformations and how they should be
|
|
* implemented, and for a description of the ASCII parameter strings.
|
|
* Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
|
|
*/
|
|
png_charp pcal_purpose; /* pCAL chunk description string */
|
|
png_int_32 pcal_X0; /* minimum value */
|
|
png_int_32 pcal_X1; /* maximum value */
|
|
png_charp pcal_units; /* Latin-1 string giving physical units */
|
|
png_charpp pcal_params; /* ASCII strings containing parameter values */
|
|
png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */
|
|
png_byte pcal_nparams; /* number of parameters given in pcal_params */
|
|
#endif
|
|
|
|
/* New members added in libpng-1.0.6 */
|
|
png_uint_32 free_me; /* flags items libpng is responsible for freeing */
|
|
|
|
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
|
|
defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
|
|
/* Storage for unknown chunks that the library doesn't recognize. */
|
|
png_unknown_chunkp unknown_chunks;
|
|
png_size_t unknown_chunks_num;
|
|
#endif
|
|
|
|
#ifdef PNG_iCCP_SUPPORTED
|
|
/* iCCP chunk data. */
|
|
png_charp iccp_name; /* profile name */
|
|
png_charp iccp_profile; /* International Color Consortium profile data */
|
|
/* Note to maintainer: should be png_bytep */
|
|
png_uint_32 iccp_proflen; /* ICC profile data length */
|
|
png_byte iccp_compression; /* Always zero */
|
|
#endif
|
|
|
|
#ifdef PNG_sPLT_SUPPORTED
|
|
/* Data on sPLT chunks (there may be more than one). */
|
|
png_sPLT_tp splt_palettes;
|
|
png_uint_32 splt_palettes_num;
|
|
#endif
|
|
|
|
#ifdef PNG_sCAL_SUPPORTED
|
|
/* The sCAL chunk describes the actual physical dimensions of the
|
|
* subject matter of the graphic. The chunk contains a unit specification
|
|
* a byte value, and two ASCII strings representing floating-point
|
|
* values. The values are width and height corresponsing to one pixel
|
|
* in the image. This external representation is converted to double
|
|
* here. Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.
|
|
*/
|
|
png_byte scal_unit; /* unit of physical scale */
|
|
#ifdef PNG_FLOATING_POINT_SUPPORTED
|
|
double scal_pixel_width; /* width of one pixel */
|
|
double scal_pixel_height; /* height of one pixel */
|
|
#endif
|
|
#ifdef PNG_FIXED_POINT_SUPPORTED
|
|
png_charp scal_s_width; /* string containing height */
|
|
png_charp scal_s_height; /* string containing width */
|
|
#endif
|
|
#endif
|
|
|
|
#ifdef PNG_INFO_IMAGE_SUPPORTED
|
|
/* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
|
|
non-zero */
|
|
/* Data valid if (valid & PNG_INFO_IDAT) non-zero */
|
|
png_bytepp row_pointers; /* the image bits */
|
|
#endif
|
|
|
|
#if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)
|
|
png_fixed_point int_gamma; /* gamma of image, if (valid & PNG_INFO_gAMA) */
|
|
#endif
|
|
|
|
#if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)
|
|
png_fixed_point int_x_white;
|
|
png_fixed_point int_y_white;
|
|
png_fixed_point int_x_red;
|
|
png_fixed_point int_y_red;
|
|
png_fixed_point int_x_green;
|
|
png_fixed_point int_y_green;
|
|
png_fixed_point int_x_blue;
|
|
png_fixed_point int_y_blue;
|
|
#endif
|
|
|
|
};
|
|
#endif /* PNGINFO_H */
|