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255 lines
12 KiB
PHP
255 lines
12 KiB
PHP
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; pnginfo.inc - header file for PNG reference library
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; Last changed in libpng 1.6.1 [March 28, 2013]
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; Copyright (c) 1998-2002,2004,2006-2013 Glenn Randers-Pehrson
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; (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
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; (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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; This code is released under the libpng license.
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; For conditions of distribution and use, see the disclaimer
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; and license in png.inc
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; png_info is a structure that holds the information in a PNG file so
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; that the application can find out the characteristics of the image.
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; If you are reading the file, this structure will tell you what is
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; in the PNG file. If you are writing the file, fill in the information
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; you want to put into the PNG file, using png_set_*() functions, then
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; call png_write_info().
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; The names chosen should be very close to the PNG specification, so
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; consult that document for information about the meaning of each field.
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; With libpng < 0.95, it was only possible to directly set and read the
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; the values in the png_info_struct, which meant that the contents and
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; order of the values had to remain fixed. With libpng 0.95 and later,
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; however, there are now functions that abstract the contents of
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; png_info_struct from the application, so this makes it easier to use
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; libpng with dynamic libraries, and even makes it possible to use
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; libraries that don't have all of the libpng ancillary chunk-handing
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; functionality. In libpng-1.5.0 this was moved into a separate private
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; file that is not visible to applications.
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; The following members may have allocated storage attached that should be
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; cleaned up before the structure is discarded: palette, trans, text,
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; pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
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; splt_palettes, scal_unit, row_pointers, and unknowns. By default, these
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; are automatically freed when the info structure is deallocated, if they were
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; allocated internally by libpng. This behavior can be changed by means
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; of the png_data_freer() function.
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; More allocation details: all the chunk-reading functions that
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; change these members go through the corresponding png_set_*
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; functions. A function to clear these members is available: see
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; png_free_data(). The png_set_* functions do not depend on being
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; able to point info structure members to any of the storage they are
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; passed (they make their own copies), EXCEPT that the png_set_text
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; functions use the same storage passed to them in the text_ptr or
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; itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
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; functions do not make their own copies.
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struct png_info_def
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; The following are necessary for every PNG file
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width dd ? ;uint_32 ;width of image in pixels (from IHDR)
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height dd ? ;uint_32 ;height of image in pixels (from IHDR)
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valid dd ? ;uint_32 ;valid chunk data (see PNG_INFO_ below)
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rowbytes dd ? ;png_size_t ;bytes needed to hold an untransformed row
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palette dd ? ;png_colorp ; array of color values (valid & PNG_INFO_PLTE)
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num_palette dw ? ;uint_16 ;number of color entries in "palette" (PLTE)
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num_trans dw ? ;uint_16 ;number of transparent palette color (tRNS)
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bit_depth db ? ;byte ;1, 2, 4, 8, or 16 bits/channel (from IHDR)
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color_type db ? ;byte ;see PNG_COLOR_TYPE_ below (from IHDR)
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; The following three should have been named *_method not *_type
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compression_type db ? ;byte ;must be PNG_COMPRESSION_TYPE_BASE (IHDR)
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filter_type db ? ;byte ;must be PNG_FILTER_TYPE_BASE (from IHDR)
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interlace_type db ? ;byte ;One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7
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; The following are set by png_set_IHDR, called from the application on
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; write, but the are never actually used by the write code.
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channels db ? ;byte ;number of data channels per pixel (1, 2, 3, 4)
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pixel_depth db ? ;byte ;number of bits per pixel
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spare_byte db ? ;byte ;to align the data, and for future use
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if PNG_READ_SUPPORTED eq 1
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; This is never set during write
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signature db 8 ;byte[8] ;magic bytes read by libpng from start of file
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end if
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; The rest of the data is optional. If you are reading, check the
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; valid field to see if the information in these are valid. If you
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; are writing, set the valid field to those chunks you want written,
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; and initialize the appropriate fields below.
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if (PNG_COLORSPACE_SUPPORTED eq 1) | (PNG_GAMMA_SUPPORTED eq 1)
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; png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are
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; defined. When COLORSPACE is switched on all the colorspace-defining
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; chunks should be enabled, when GAMMA is switched on all the gamma-defining
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; chunks should be enabled. If this is not done it becomes possible to read
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; inconsistent PNG files and assign a probably incorrect interpretation to
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; the information. (In other words, by carefully choosing which chunks to
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; recognize the system configuration can select an interpretation for PNG
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; files containing ambiguous data and this will result in inconsistent
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; behavior between different libpng builds!)
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colorspace png_colorspace
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end if
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if PNG_iCCP_SUPPORTED eq 1
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; iCCP chunk data.
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iccp_name dd ? ;charp ;profile name
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iccp_profile dd ? ;bytep ;International Color Consortium profile data
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iccp_proflen dd ? ;uint_32 ;ICC profile data length
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end if
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if PNG_TEXT_SUPPORTED eq 1
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; The tEXt, and zTXt chunks contain human-readable textual data in
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; uncompressed, compressed, and optionally compressed forms, respectively.
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; The data in "text" is an array of pointers to uncompressed,
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; null-terminated C strings. Each chunk has a keyword that describes the
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; textual data contained in that chunk. Keywords are not required to be
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; unique, and the text string may be empty. Any number of text chunks may
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; be in an image.
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num_text dd ? ;int ;number of comments read or comments to write
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max_text dd ? ;int ;current size of text array
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text dd ? ;png_textp ;array of comments read or comments to write
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end if ;TEXT
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if PNG_tIME_SUPPORTED eq 1
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; The tIME chunk holds the last time the displayed image data was
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; modified. See the png_time struct for the contents of this struct.
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mod_time png_time
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end if
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if PNG_sBIT_SUPPORTED eq 1
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; The sBIT chunk specifies the number of significant high-order bits
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; in the pixel data. Values are in the range [1, bit_depth], and are
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; only specified for the channels in the pixel data. The contents of
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; the low-order bits is not specified. Data is valid if
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; (valid & PNG_INFO_sBIT) is non-zero.
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sig_bit png_color_8 ; significant bits in color channels
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end if
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;#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
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;defined(PNG_READ_BACKGROUND_SUPPORTED)
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; The tRNS chunk supplies transparency data for paletted images and
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; other image types that don't need a full alpha channel. There are
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; "num_trans" transparency values for a paletted image, stored in the
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; same order as the palette colors, starting from index 0. Values
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; for the data are in the range [0, 255], ranging from fully transparent
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; to fully opaque, respectively. For non-paletted images, there is a
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; single color specified that should be treated as fully transparent.
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; Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
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trans_alpha dd ? ;bytep ; alpha values for paletted image
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trans_color png_color_16 ;transparent color for non-palette image
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;end if
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if (PNG_bKGD_SUPPORTED eq 1) | (PNG_READ_BACKGROUND_SUPPORTED eq 1)
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; The bKGD chunk gives the suggested image background color if the
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; display program does not have its own background color and the image
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; is needs to composited onto a background before display. The colors
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; in "background" are normally in the same color space/depth as the
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; pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
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background png_color_16
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end if
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if PNG_oFFs_SUPPORTED eq 1
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; The oFFs chunk gives the offset in "offset_unit_type" units rightwards
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; and downwards from the top-left corner of the display, page, or other
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; application-specific co-ordinate space. See the PNG_OFFSET_ defines
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; below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero.
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x_offset dd ? ;int_32 ;x offset on page
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y_offset dd ? ;int_32 ;y offset on page
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offset_unit_type db ? ;byte ;offset units type
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end if
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if PNG_pHYs_SUPPORTED eq 1
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; The pHYs chunk gives the physical pixel density of the image for
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; display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
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; defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
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x_pixels_per_unit dd ? ;uint_32 ;horizontal pixel density
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y_pixels_per_unit dd ? ;uint_32 ;vertical pixel density
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phys_unit_type db ? ;byte ;resolution type (see PNG_RESOLUTION_ below)
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end if
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if PNG_hIST_SUPPORTED eq 1
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; The hIST chunk contains the relative frequency or importance of the
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; various palette entries, so that a viewer can intelligently select a
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; reduced-color palette, if required. Data is an array of "num_palette"
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; values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
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; is non-zero.
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hist dd ? ;uint_16p
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end if
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if PNG_pCAL_SUPPORTED eq 1
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; The pCAL chunk describes a transformation between the stored pixel
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; values and original physical data values used to create the image.
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; The integer range [0, 2^bit_depth - 1] maps to the floating-point
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; range given by [pcal_X0, pcal_X1], and are further transformed by a
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; (possibly non-linear) transformation function given by "pcal_type"
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; and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_
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; defines below, and the PNG-Group's PNG extensions document for a
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; complete description of the transformations and how they should be
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; implemented, and for a description of the ASCII parameter strings.
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; Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
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pcal_purpose dd ? ;charp ;pCAL chunk description string
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pcal_X0 dd ? ;int_32 ;minimum value
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pcal_X1 dd ? ;int_32 ;maximum value
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pcal_units dd ? ;charp ;Latin-1 string giving physical units
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pcal_params dd ? ;charpp ;ASCII strings containing parameter values
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pcal_type db ? ;byte ;equation type (see PNG_EQUATION_ below)
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pcal_nparams db ? ;byte ;number of parameters given in pcal_params
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end if
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; New members added in libpng-1.0.6
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free_me dd ? ;uint_32 ;flags items libpng is responsible for freeing
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if PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED eq 1
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; Storage for unknown chunks that the library doesn't recognize.
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unknown_chunks dd ? ;png_unknown_chunkp
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; The type of this field is limited by the type of
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; png_struct::user_chunk_cache_max, else overflow can occur.
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unknown_chunks_num dd ? ;int
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end if
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if PNG_sPLT_SUPPORTED eq 1
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; Data on sPLT chunks (there may be more than one).
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splt_palettes dd ? ;png_sPLT_tp
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splt_palettes_num dd ? ;int ;Match type returned by png_get API
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end if
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if PNG_sCAL_SUPPORTED eq 1
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; The sCAL chunk describes the actual physical dimensions of the
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; subject matter of the graphic. The chunk contains a unit specification
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; a byte value, and two ASCII strings representing floating-point
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; values. The values are width and height corresponsing to one pixel
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; in the image. Data values are valid if (valid & PNG_INFO_sCAL) is
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; non-zero.
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scal_unit db ? ;byte ;unit of physical scale
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scal_s_width dd ? ;charp ;string containing height
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scal_s_height dd ? ;charp ;string containing width
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end if
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if PNG_INFO_IMAGE_SUPPORTED eq 1
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; Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
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; non-zero
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; Data valid if (valid & PNG_INFO_IDAT) non-zero
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row_pointers dd ? ;bytepp ;the image bits
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end if
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ends
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