| /* 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, 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 any case, the order of the parameters in png_info_struct should NOT |
| * be changed for as long as possible to keep compatibility with applications |
| * that use the old direct-access method with png_info_struct. |
| * |
| * 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. |
| */ |
| typedef struct png_info_struct |
| { |
| /* the following are necessary for every PNG file */ |
| png_uint_32 width PNG_DEPSTRUCT; /* width of image in pixels (from IHDR) */ |
| png_uint_32 height PNG_DEPSTRUCT; /* height of image in pixels (from IHDR) */ |
| png_uint_32 valid PNG_DEPSTRUCT; /* valid chunk data (see PNG_INFO_ |
| below) */ |
| png_size_t rowbytes PNG_DEPSTRUCT; /* bytes needed to hold an untransformed |
| row */ |
| png_colorp palette PNG_DEPSTRUCT; /* array of color values |
| (valid & PNG_INFO_PLTE) */ |
| png_uint_16 num_palette PNG_DEPSTRUCT; /* number of color entries in |
| "palette" (PLTE) */ |
| png_uint_16 num_trans PNG_DEPSTRUCT; /* number of transparent palette |
| color (tRNS) */ |
| png_byte bit_depth PNG_DEPSTRUCT; /* 1, 2, 4, 8, or 16 bits/channel |
| (from IHDR) */ |
| png_byte color_type PNG_DEPSTRUCT; /* see PNG_COLOR_TYPE_ below |
| (from IHDR) */ |
| /* The following three should have been named *_method not *_type */ |
| png_byte compression_type PNG_DEPSTRUCT; /* must be |
| PNG_COMPRESSION_TYPE_BASE (IHDR) */ |
| png_byte filter_type PNG_DEPSTRUCT; /* must be PNG_FILTER_TYPE_BASE |
| (from IHDR) */ |
| png_byte interlace_type PNG_DEPSTRUCT; /* One of PNG_INTERLACE_NONE, |
| PNG_INTERLACE_ADAM7 */ |
| |
| /* The following is informational only on read, and not used on writes. */ |
| png_byte channels PNG_DEPSTRUCT; /* number of data channels per |
| pixel (1, 2, 3, 4) */ |
| png_byte pixel_depth PNG_DEPSTRUCT; /* number of bits per pixel */ |
| png_byte spare_byte PNG_DEPSTRUCT; /* to align the data, and for |
| future use */ |
| png_byte signature[8] PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; /* number of comments read/to write */ |
| int max_text PNG_DEPSTRUCT; /* current size of text array */ |
| png_textp text PNG_DEPSTRUCT; /* array of comments read/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 PNG_DEPSTRUCT; |
| #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 PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; /* alpha values for paletted |
| image */ |
| png_color_16 trans_color PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; |
| #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 PNG_DEPSTRUCT; /* x offset on page */ |
| png_int_32 y_offset PNG_DEPSTRUCT; /* y offset on page */ |
| png_byte offset_unit_type PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; /* horizontal pixel density */ |
| png_uint_32 y_pixels_per_unit PNG_DEPSTRUCT; /* vertical pixel density */ |
| png_byte phys_unit_type PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; |
| #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 PNG_DEPSTRUCT; |
| float y_white PNG_DEPSTRUCT; |
| float x_red PNG_DEPSTRUCT; |
| float y_red PNG_DEPSTRUCT; |
| float x_green PNG_DEPSTRUCT; |
| float y_green PNG_DEPSTRUCT; |
| float x_blue PNG_DEPSTRUCT; |
| float y_blue PNG_DEPSTRUCT; |
| #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 PNG_DEPSTRUCT; /* pCAL chunk description string */ |
| png_int_32 pcal_X0 PNG_DEPSTRUCT; /* minimum value */ |
| png_int_32 pcal_X1 PNG_DEPSTRUCT; /* maximum value */ |
| png_charp pcal_units PNG_DEPSTRUCT; /* Latin-1 string giving physical |
| units */ |
| png_charpp pcal_params PNG_DEPSTRUCT; /* ASCII strings containing |
| parameter values */ |
| png_byte pcal_type PNG_DEPSTRUCT; /* equation type |
| (see PNG_EQUATION_ below) */ |
| png_byte pcal_nparams PNG_DEPSTRUCT; /* number of parameters given |
| in pcal_params */ |
| #endif |
| |
| /* New members added in libpng-1.0.6 */ |
| png_uint_32 free_me PNG_DEPSTRUCT; /* 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_DEPSTRUCT; |
| png_size_t unknown_chunks_num PNG_DEPSTRUCT; |
| #endif |
| |
| #ifdef PNG_iCCP_SUPPORTED |
| /* iCCP chunk data. */ |
| png_charp iccp_name PNG_DEPSTRUCT; /* profile name */ |
| png_charp iccp_profile PNG_DEPSTRUCT; /* International Color Consortium |
| profile data */ |
| /* Note to maintainer: should be png_bytep */ |
| png_uint_32 iccp_proflen PNG_DEPSTRUCT; /* ICC profile data length */ |
| png_byte iccp_compression PNG_DEPSTRUCT; /* Always zero */ |
| #endif |
| |
| #ifdef PNG_sPLT_SUPPORTED |
| /* Data on sPLT chunks (there may be more than one). */ |
| png_sPLT_tp splt_palettes PNG_DEPSTRUCT; |
| png_uint_32 splt_palettes_num PNG_DEPSTRUCT; |
| #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 PNG_DEPSTRUCT; /* unit of physical scale */ |
| #ifdef PNG_FLOATING_POINT_SUPPORTED |
| double scal_pixel_width PNG_DEPSTRUCT; /* width of one pixel */ |
| double scal_pixel_height PNG_DEPSTRUCT; /* height of one pixel */ |
| #endif |
| #ifdef PNG_FIXED_POINT_SUPPORTED |
| png_charp scal_s_width PNG_DEPSTRUCT; /* string containing height */ |
| png_charp scal_s_height PNG_DEPSTRUCT; /* 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 PNG_DEPSTRUCT; /* the image bits */ |
| #endif |
| |
| #if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED) |
| png_fixed_point int_gamma PNG_DEPSTRUCT; /* 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_DEPSTRUCT; |
| png_fixed_point int_y_white PNG_DEPSTRUCT; |
| png_fixed_point int_x_red PNG_DEPSTRUCT; |
| png_fixed_point int_y_red PNG_DEPSTRUCT; |
| png_fixed_point int_x_green PNG_DEPSTRUCT; |
| png_fixed_point int_y_green PNG_DEPSTRUCT; |
| png_fixed_point int_x_blue PNG_DEPSTRUCT; |
| png_fixed_point int_y_blue PNG_DEPSTRUCT; |
| #endif |
| |
| } png_info; |
