Rewritten StreamTexture for better code reuse, added basis universal support

1 files changed, 1930 insertions, 0 deletions

diff --git a/thirdparty/basis_universal/lodepng.h b/thirdparty/basis_universal/lodepng.h
new file mode 100644
index 0000000000..476a2061e2
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+++ b/thirdparty/basis_universal/lodepng.h
@@ -0,0 +1,1930 @@
+/*
+LodePNG version 20190210
+
+Copyright (c) 2005-2019 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+#ifndef LODEPNG_H
+#define LODEPNG_H
+
+#include <string.h> /*for size_t*/
+
+extern const char* LODEPNG_VERSION_STRING;
+
+/*
+The following #defines are used to create code sections. They can be disabled
+to disable code sections, which can give faster compile time and smaller binary.
+The "NO_COMPILE" defines are designed to be used to pass as defines to the
+compiler command to disable them without modifying this header, e.g.
+-DLODEPNG_NO_COMPILE_ZLIB for gcc.
+In addition to those below, you can also define LODEPNG_NO_COMPILE_CRC to
+allow implementing a custom lodepng_crc32.
+*/
+/*deflate & zlib. If disabled, you must specify alternative zlib functions in
+the custom_zlib field of the compress and decompress settings*/
+#ifndef LODEPNG_NO_COMPILE_ZLIB
+#define LODEPNG_COMPILE_ZLIB
+#endif
+
+/*png encoder and png decoder*/
+#ifndef LODEPNG_NO_COMPILE_PNG
+#define LODEPNG_COMPILE_PNG
+#endif
+
+/*deflate&zlib decoder and png decoder*/
+#ifndef LODEPNG_NO_COMPILE_DECODER
+#define LODEPNG_COMPILE_DECODER
+#endif
+
+/*deflate&zlib encoder and png encoder*/
+#ifndef LODEPNG_NO_COMPILE_ENCODER
+#define LODEPNG_COMPILE_ENCODER
+#endif
+
+/*the optional built in harddisk file loading and saving functions*/
+#ifndef LODEPNG_NO_COMPILE_DISK
+#define LODEPNG_COMPILE_DISK
+#endif
+
+/*support for chunks other than IHDR, IDAT, PLTE, tRNS, IEND: ancillary and unknown chunks*/
+#ifndef LODEPNG_NO_COMPILE_ANCILLARY_CHUNKS
+#define LODEPNG_COMPILE_ANCILLARY_CHUNKS
+#endif
+
+/*ability to convert error numerical codes to English text string*/
+#ifndef LODEPNG_NO_COMPILE_ERROR_TEXT
+#define LODEPNG_COMPILE_ERROR_TEXT
+#endif
+
+/*Compile the default allocators (C's free, malloc and realloc). If you disable this,
+you can define the functions lodepng_free, lodepng_malloc and lodepng_realloc in your
+source files with custom allocators.*/
+#ifndef LODEPNG_NO_COMPILE_ALLOCATORS
+#define LODEPNG_COMPILE_ALLOCATORS
+#endif
+
+/*compile the C++ version (you can disable the C++ wrapper here even when compiling for C++)*/
+#ifdef __cplusplus
+#ifndef LODEPNG_NO_COMPILE_CPP
+#define LODEPNG_COMPILE_CPP
+#endif
+#endif
+
+#ifdef LODEPNG_COMPILE_CPP
+#include <vector>
+#include <string>
+#endif /*LODEPNG_COMPILE_CPP*/
+
+#ifdef LODEPNG_COMPILE_PNG
+/*The PNG color types (also used for raw).*/
+typedef enum LodePNGColorType {
+  LCT_GREY = 0, /*grayscale: 1,2,4,8,16 bit*/
+  LCT_RGB = 2, /*RGB: 8,16 bit*/
+  LCT_PALETTE = 3, /*palette: 1,2,4,8 bit*/
+  LCT_GREY_ALPHA = 4, /*grayscale with alpha: 8,16 bit*/
+  LCT_RGBA = 6 /*RGB with alpha: 8,16 bit*/
+} LodePNGColorType;
+
+#ifdef LODEPNG_COMPILE_DECODER
+/*
+Converts PNG data in memory to raw pixel data.
+out: Output parameter. Pointer to buffer that will contain the raw pixel data.
+     After decoding, its size is w * h * (bytes per pixel) bytes larger than
+     initially. Bytes per pixel depends on colortype and bitdepth.
+     Must be freed after usage with free(*out).
+     Note: for 16-bit per channel colors, uses big endian format like PNG does.
+w: Output parameter. Pointer to width of pixel data.
+h: Output parameter. Pointer to height of pixel data.
+in: Memory buffer with the PNG file.
+insize: size of the in buffer.
+colortype: the desired color type for the raw output image. See explanation on PNG color types.
+bitdepth: the desired bit depth for the raw output image. See explanation on PNG color types.
+Return value: LodePNG error code (0 means no error).
+*/
+unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h,
+                               const unsigned char* in, size_t insize,
+                               LodePNGColorType colortype, unsigned bitdepth);
+
+/*Same as lodepng_decode_memory, but always decodes to 32-bit RGBA raw image*/
+unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h,
+                          const unsigned char* in, size_t insize);
+
+/*Same as lodepng_decode_memory, but always decodes to 24-bit RGB raw image*/
+unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h,
+                          const unsigned char* in, size_t insize);
+
+#ifdef LODEPNG_COMPILE_DISK
+/*
+Load PNG from disk, from file with given name.
+Same as the other decode functions, but instead takes a filename as input.
+*/
+unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h,
+                             const char* filename,
+                             LodePNGColorType colortype, unsigned bitdepth);
+
+/*Same as lodepng_decode_file, but always decodes to 32-bit RGBA raw image.*/
+unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h,
+                               const char* filename);
+
+/*Same as lodepng_decode_file, but always decodes to 24-bit RGB raw image.*/
+unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h,
+                               const char* filename);
+#endif /*LODEPNG_COMPILE_DISK*/
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*
+Converts raw pixel data into a PNG image in memory. The colortype and bitdepth
+  of the output PNG image cannot be chosen, they are automatically determined
+  by the colortype, bitdepth and content of the input pixel data.
+  Note: for 16-bit per channel colors, needs big endian format like PNG does.
+out: Output parameter. Pointer to buffer that will contain the PNG image data.
+     Must be freed after usage with free(*out).
+outsize: Output parameter. Pointer to the size in bytes of the out buffer.
+image: The raw pixel data to encode. The size of this buffer should be
+       w * h * (bytes per pixel), bytes per pixel depends on colortype and bitdepth.
+w: width of the raw pixel data in pixels.
+h: height of the raw pixel data in pixels.
+colortype: the color type of the raw input image. See explanation on PNG color types.
+bitdepth: the bit depth of the raw input image. See explanation on PNG color types.
+Return value: LodePNG error code (0 means no error).
+*/
+unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize,
+                               const unsigned char* image, unsigned w, unsigned h,
+                               LodePNGColorType colortype, unsigned bitdepth);
+
+/*Same as lodepng_encode_memory, but always encodes from 32-bit RGBA raw image.*/
+unsigned lodepng_encode32(unsigned char** out, size_t* outsize,
+                          const unsigned char* image, unsigned w, unsigned h);
+
+/*Same as lodepng_encode_memory, but always encodes from 24-bit RGB raw image.*/
+unsigned lodepng_encode24(unsigned char** out, size_t* outsize,
+                          const unsigned char* image, unsigned w, unsigned h);
+
+#ifdef LODEPNG_COMPILE_DISK
+/*
+Converts raw pixel data into a PNG file on disk.
+Same as the other encode functions, but instead takes a filename as output.
+NOTE: This overwrites existing files without warning!
+*/
+unsigned lodepng_encode_file(const char* filename,
+                             const unsigned char* image, unsigned w, unsigned h,
+                             LodePNGColorType colortype, unsigned bitdepth);
+
+/*Same as lodepng_encode_file, but always encodes from 32-bit RGBA raw image.*/
+unsigned lodepng_encode32_file(const char* filename,
+                               const unsigned char* image, unsigned w, unsigned h);
+
+/*Same as lodepng_encode_file, but always encodes from 24-bit RGB raw image.*/
+unsigned lodepng_encode24_file(const char* filename,
+                               const unsigned char* image, unsigned w, unsigned h);
+#endif /*LODEPNG_COMPILE_DISK*/
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+
+#ifdef LODEPNG_COMPILE_CPP
+namespace lodepng {
+#ifdef LODEPNG_COMPILE_DECODER
+/*Same as lodepng_decode_memory, but decodes to an std::vector. The colortype
+is the format to output the pixels to. Default is RGBA 8-bit per channel.*/
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+                const unsigned char* in, size_t insize,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+                const std::vector<unsigned char>& in,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+#ifdef LODEPNG_COMPILE_DISK
+/*
+Converts PNG file from disk to raw pixel data in memory.
+Same as the other decode functions, but instead takes a filename as input.
+*/
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+                const std::string& filename,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_DECODER */
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*Same as lodepng_encode_memory, but encodes to an std::vector. colortype
+is that of the raw input data. The output PNG color type will be auto chosen.*/
+unsigned encode(std::vector<unsigned char>& out,
+                const unsigned char* in, unsigned w, unsigned h,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+unsigned encode(std::vector<unsigned char>& out,
+                const std::vector<unsigned char>& in, unsigned w, unsigned h,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+#ifdef LODEPNG_COMPILE_DISK
+/*
+Converts 32-bit RGBA raw pixel data into a PNG file on disk.
+Same as the other encode functions, but instead takes a filename as output.
+NOTE: This overwrites existing files without warning!
+*/
+unsigned encode(const std::string& filename,
+                const unsigned char* in, unsigned w, unsigned h,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+unsigned encode(const std::string& filename,
+                const std::vector<unsigned char>& in, unsigned w, unsigned h,
+                LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_ENCODER */
+} /* namespace lodepng */
+#endif /*LODEPNG_COMPILE_CPP*/
+#endif /*LODEPNG_COMPILE_PNG*/
+
+#ifdef LODEPNG_COMPILE_ERROR_TEXT
+/*Returns an English description of the numerical error code.*/
+const char* lodepng_error_text(unsigned code);
+#endif /*LODEPNG_COMPILE_ERROR_TEXT*/
+
+#ifdef LODEPNG_COMPILE_DECODER
+/*Settings for zlib decompression*/
+typedef struct LodePNGDecompressSettings LodePNGDecompressSettings;
+struct LodePNGDecompressSettings {
+  /* Check LodePNGDecoderSettings for more ignorable errors such as ignore_crc */
+  unsigned ignore_adler32; /*if 1, continue and don't give an error message if the Adler32 checksum is corrupted*/
+
+  /*use custom zlib decoder instead of built in one (default: null)*/
+  unsigned (*custom_zlib)(unsigned char**, size_t*,
+                          const unsigned char*, size_t,
+                          const LodePNGDecompressSettings*);
+  /*use custom deflate decoder instead of built in one (default: null)
+  if custom_zlib is used, custom_deflate is ignored since only the built in
+  zlib function will call custom_deflate*/
+  unsigned (*custom_inflate)(unsigned char**, size_t*,
+                             const unsigned char*, size_t,
+                             const LodePNGDecompressSettings*);
+
+  const void* custom_context; /*optional custom settings for custom functions*/
+};
+
+extern const LodePNGDecompressSettings lodepng_default_decompress_settings;
+void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings);
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*
+Settings for zlib compression. Tweaking these settings tweaks the balance
+between speed and compression ratio.
+*/
+typedef struct LodePNGCompressSettings LodePNGCompressSettings;
+struct LodePNGCompressSettings /*deflate = compress*/ {
+  /*LZ77 related settings*/
+  unsigned btype; /*the block type for LZ (0, 1, 2 or 3, see zlib standard). Should be 2 for proper compression.*/
+  unsigned use_lz77; /*whether or not to use LZ77. Should be 1 for proper compression.*/
+  unsigned windowsize; /*must be a power of two <= 32768. higher compresses more but is slower. Default value: 2048.*/
+  unsigned minmatch; /*mininum lz77 length. 3 is normally best, 6 can be better for some PNGs. Default: 0*/
+  unsigned nicematch; /*stop searching if >= this length found. Set to 258 for best compression. Default: 128*/
+  unsigned lazymatching; /*use lazy matching: better compression but a bit slower. Default: true*/
+
+  /*use custom zlib encoder instead of built in one (default: null)*/
+  unsigned (*custom_zlib)(unsigned char**, size_t*,
+                          const unsigned char*, size_t,
+                          const LodePNGCompressSettings*);
+  /*use custom deflate encoder instead of built in one (default: null)
+  if custom_zlib is used, custom_deflate is ignored since only the built in
+  zlib function will call custom_deflate*/
+  unsigned (*custom_deflate)(unsigned char**, size_t*,
+                             const unsigned char*, size_t,
+                             const LodePNGCompressSettings*);
+
+  const void* custom_context; /*optional custom settings for custom functions*/
+};
+
+extern const LodePNGCompressSettings lodepng_default_compress_settings;
+void lodepng_compress_settings_init(LodePNGCompressSettings* settings);
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+#ifdef LODEPNG_COMPILE_PNG
+/*
+Color mode of an image. Contains all information required to decode the pixel
+bits to RGBA colors. This information is the same as used in the PNG file
+format, and is used both for PNG and raw image data in LodePNG.
+*/
+typedef struct LodePNGColorMode {
+  /*header (IHDR)*/
+  LodePNGColorType colortype; /*color type, see PNG standard or documentation further in this header file*/
+  unsigned bitdepth;  /*bits per sample, see PNG standard or documentation further in this header file*/
+
+  /*
+  palette (PLTE and tRNS)
+
+  Dynamically allocated with the colors of the palette, including alpha.
+  When encoding a PNG, to store your colors in the palette of the LodePNGColorMode, first use
+  lodepng_palette_clear, then for each color use lodepng_palette_add.
+  If you encode an image without alpha with palette, don't forget to put value 255 in each A byte of the palette.
+
+  When decoding, by default you can ignore this palette, since LodePNG already
+  fills the palette colors in the pixels of the raw RGBA output.
+
+  The palette is only supported for color type 3.
+  */
+  unsigned char* palette; /*palette in RGBARGBA... order. When allocated, must be either 0, or have size 1024*/
+  size_t palettesize; /*palette size in number of colors (amount of bytes is 4 * palettesize)*/
+
+  /*
+  transparent color key (tRNS)
+
+  This color uses the same bit depth as the bitdepth value in this struct, which can be 1-bit to 16-bit.
+  For grayscale PNGs, r, g and b will all 3 be set to the same.
+
+  When decoding, by default you can ignore this information, since LodePNG sets
+  pixels with this key to transparent already in the raw RGBA output.
+
+  The color key is only supported for color types 0 and 2.
+  */
+  unsigned key_defined; /*is a transparent color key given? 0 = false, 1 = true*/
+  unsigned key_r;       /*red/grayscale component of color key*/
+  unsigned key_g;       /*green component of color key*/
+  unsigned key_b;       /*blue component of color key*/
+} LodePNGColorMode;
+
+/*init, cleanup and copy functions to use with this struct*/
+void lodepng_color_mode_init(LodePNGColorMode* info);
+void lodepng_color_mode_cleanup(LodePNGColorMode* info);
+/*return value is error code (0 means no error)*/
+unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source);
+/* Makes a temporary LodePNGColorMode that does not need cleanup (no palette) */
+LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth);
+
+void lodepng_palette_clear(LodePNGColorMode* info);
+/*add 1 color to the palette*/
+unsigned lodepng_palette_add(LodePNGColorMode* info,
+                             unsigned char r, unsigned char g, unsigned char b, unsigned char a);
+
+/*get the total amount of bits per pixel, based on colortype and bitdepth in the struct*/
+unsigned lodepng_get_bpp(const LodePNGColorMode* info);
+/*get the amount of color channels used, based on colortype in the struct.
+If a palette is used, it counts as 1 channel.*/
+unsigned lodepng_get_channels(const LodePNGColorMode* info);
+/*is it a grayscale type? (only colortype 0 or 4)*/
+unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info);
+/*has it got an alpha channel? (only colortype 2 or 6)*/
+unsigned lodepng_is_alpha_type(const LodePNGColorMode* info);
+/*has it got a palette? (only colortype 3)*/
+unsigned lodepng_is_palette_type(const LodePNGColorMode* info);
+/*only returns true if there is a palette and there is a value in the palette with alpha < 255.
+Loops through the palette to check this.*/
+unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info);
+/*
+Check if the given color info indicates the possibility of having non-opaque pixels in the PNG image.
+Returns true if the image can have translucent or invisible pixels (it still be opaque if it doesn't use such pixels).
+Returns false if the image can only have opaque pixels.
+In detail, it returns true only if it's a color type with alpha, or has a palette with non-opaque values,
+or if "key_defined" is true.
+*/
+unsigned lodepng_can_have_alpha(const LodePNGColorMode* info);
+/*Returns the byte size of a raw image buffer with given width, height and color mode*/
+size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color);
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*The information of a Time chunk in PNG.*/
+typedef struct LodePNGTime {
+  unsigned year;    /*2 bytes used (0-65535)*/
+  unsigned month;   /*1-12*/
+  unsigned day;     /*1-31*/
+  unsigned hour;    /*0-23*/
+  unsigned minute;  /*0-59*/
+  unsigned second;  /*0-60 (to allow for leap seconds)*/
+} LodePNGTime;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+/*Information about the PNG image, except pixels, width and height.*/
+typedef struct LodePNGInfo {
+  /*header (IHDR), palette (PLTE) and transparency (tRNS) chunks*/
+  unsigned compression_method;/*compression method of the original file. Always 0.*/
+  unsigned filter_method;     /*filter method of the original file*/
+  unsigned interlace_method;  /*interlace method of the original file: 0=none, 1=Adam7*/
+  LodePNGColorMode color;     /*color type and bits, palette and transparency of the PNG file*/
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+  /*
+  Suggested background color chunk (bKGD)
+
+  This uses the same color mode and bit depth as the PNG (except no alpha channel),
+  with values truncated to the bit depth in the unsigned integer.
+
+  For grayscale and palette PNGs, the value is stored in background_r. The values
+  in background_g and background_b are then unused.
+
+  So when decoding, you may get these in a different color mode than the one you requested
+  for the raw pixels.
+
+  When encoding with auto_convert, you must use the color model defined in info_png.color for
+  these values. The encoder normally ignores info_png.color when auto_convert is on, but will
+  use it to interpret these values (and convert copies of them to its chosen color model).
+
+  When encoding, avoid setting this to an expensive color, such as a non-gray value
+  when the image is gray, or the compression will be worse since it will be forced to
+  write the PNG with a more expensive color mode (when auto_convert is on).
+
+  The decoder does not use this background color to edit the color of pixels. This is a
+  completely optional metadata feature.
+  */
+  unsigned background_defined; /*is a suggested background color given?*/
+  unsigned background_r;       /*red/gray/palette component of suggested background color*/
+  unsigned background_g;       /*green component of suggested background color*/
+  unsigned background_b;       /*blue component of suggested background color*/
+
+  /*
+  non-international text chunks (tEXt and zTXt)
+
+  The char** arrays each contain num strings. The actual messages are in
+  text_strings, while text_keys are keywords that give a short description what
+  the actual text represents, e.g. Title, Author, Description, or anything else.
+
+  All the string fields below including keys, names and language tags are null terminated.
+  The PNG specification uses null characters for the keys, names and tags, and forbids null
+  characters to appear in the main text which is why we can use null termination everywhere here.
+
+  A keyword is minimum 1 character and maximum 79 characters long. It's
+  discouraged to use a single line length longer than 79 characters for texts.
+
+  Don't allocate these text buffers yourself. Use the init/cleanup functions
+  correctly and use lodepng_add_text and lodepng_clear_text.
+  */
+  size_t text_num; /*the amount of texts in these char** buffers (there may be more texts in itext)*/
+  char** text_keys; /*the keyword of a text chunk (e.g. "Comment")*/
+  char** text_strings; /*the actual text*/
+
+  /*
+  international text chunks (iTXt)
+  Similar to the non-international text chunks, but with additional strings
+  "langtags" and "transkeys".
+  */
+  size_t itext_num; /*the amount of international texts in this PNG*/
+  char** itext_keys; /*the English keyword of the text chunk (e.g. "Comment")*/
+  char** itext_langtags; /*language tag for this text's language, ISO/IEC 646 string, e.g. ISO 639 language tag*/
+  char** itext_transkeys; /*keyword translated to the international language - UTF-8 string*/
+  char** itext_strings; /*the actual international text - UTF-8 string*/
+
+  /*time chunk (tIME)*/
+  unsigned time_defined; /*set to 1 to make the encoder generate a tIME chunk*/
+  LodePNGTime time;
+
+  /*phys chunk (pHYs)*/
+  unsigned phys_defined; /*if 0, there is no pHYs chunk and the values below are undefined, if 1 else there is one*/
+  unsigned phys_x; /*pixels per unit in x direction*/
+  unsigned phys_y; /*pixels per unit in y direction*/
+  unsigned phys_unit; /*may be 0 (unknown unit) or 1 (metre)*/
+
+  /*
+  Color profile related chunks: gAMA, cHRM, sRGB, iCPP
+
+  LodePNG does not apply any color conversions on pixels in the encoder or decoder and does not interpret these color
+  profile values. It merely passes on the information. If you wish to use color profiles and convert colors, please
+  use these values with a color management library.
+
+  See the PNG, ICC and sRGB specifications for more information about the meaning of these values.
+  */
+
+  /* gAMA chunk: optional, overridden by sRGB or iCCP if those are present. */
+  unsigned gama_defined; /* Whether a gAMA chunk is present (0 = not present, 1 = present). */
+  unsigned gama_gamma;   /* Gamma exponent times 100000 */
+
+  /* cHRM chunk: optional, overridden by sRGB or iCCP if those are present. */
+  unsigned chrm_defined; /* Whether a cHRM chunk is present (0 = not present, 1 = present). */
+  unsigned chrm_white_x; /* White Point x times 100000 */
+  unsigned chrm_white_y; /* White Point y times 100000 */
+  unsigned chrm_red_x;   /* Red x times 100000 */
+  unsigned chrm_red_y;   /* Red y times 100000 */
+  unsigned chrm_green_x; /* Green x times 100000 */
+  unsigned chrm_green_y; /* Green y times 100000 */
+  unsigned chrm_blue_x;  /* Blue x times 100000 */
+  unsigned chrm_blue_y;  /* Blue y times 100000 */
+
+  /*
+  sRGB chunk: optional. May not appear at the same time as iCCP.
+  If gAMA is also present gAMA must contain value 45455.
+  If cHRM is also present cHRM must contain respectively 31270,32900,64000,33000,30000,60000,15000,6000.
+  */
+  unsigned srgb_defined; /* Whether an sRGB chunk is present (0 = not present, 1 = present). */
+  unsigned srgb_intent;  /* Rendering intent: 0=perceptual, 1=rel. colorimetric, 2=saturation, 3=abs. colorimetric */
+
+  /*
+  iCCP chunk: optional. May not appear at the same time as sRGB.
+
+  LodePNG does not parse or use the ICC profile (except its color space header field for an edge case), a
+  separate library to handle the ICC data (not included in LodePNG) format is needed to use it for color
+  management and conversions.
+
+  For encoding, if iCCP is present, gAMA and cHRM are recommended to be added as well with values that match the ICC
+  profile as closely as possible, if you wish to do this you should provide the correct values for gAMA and cHRM and
+  enable their '_defined' flags since LodePNG will not automatically compute them from the ICC profile.
+
+  For encoding, the ICC profile is required by the PNG specification to be an "RGB" profile for non-gray
+  PNG color types and a "GRAY" profile for gray PNG color types. If you disable auto_convert, you must ensure
+  the ICC profile type matches your requested color type, else the encoder gives an error. If auto_convert is
+  enabled (the default), and the ICC profile is not a good match for the pixel data, this will result in an encoder
+  error if the pixel data has non-gray pixels for a GRAY profile, or a silent less-optimal compression of the pixel
+  data if the pixels could be encoded as grayscale but the ICC profile is RGB.
+
+  To avoid this do not set an ICC profile in the image unless there is a good reason for it, and when doing so
+  make sure you compute it carefully to avoid the above problems.
+  */
+  unsigned iccp_defined;      /* Whether an iCCP chunk is present (0 = not present, 1 = present). */
+  char* iccp_name;            /* Null terminated string with profile name, 1-79 bytes */
+  /*
+  The ICC profile in iccp_profile_size bytes.
+  Don't allocate this buffer yourself. Use the init/cleanup functions
+  correctly and use lodepng_set_icc and lodepng_clear_icc.
+  */
+  unsigned char* iccp_profile;
+  unsigned iccp_profile_size; /* The size of iccp_profile in bytes */
+
+  /* End of color profile related chunks */
+
+
+  /*
+  unknown chunks: chunks not known by LodePNG, passed on byte for byte.
+
+  There are 3 buffers, one for each position in the PNG where unknown chunks can appear.
+  Each buffer contains all unknown chunks for that position consecutively.
+  The 3 positions are:
+  0: between IHDR and PLTE, 1: between PLTE and IDAT, 2: between IDAT and IEND.
+
+  For encoding, do not store critical chunks or known chunks that are enabled with a "_defined" flag
+  above in here, since the encoder will blindly follow this and could then encode an invalid PNG file
+  (such as one with two IHDR chunks or the disallowed combination of sRGB with iCCP). But do use
+  this if you wish to store an ancillary chunk that is not supported by LodePNG (such as sPLT or hIST),
+  or any non-standard PNG chunk.
+
+  Do not allocate or traverse this data yourself. Use the chunk traversing functions declared
+  later, such as lodepng_chunk_next and lodepng_chunk_append, to read/write this struct.
+  */
+  unsigned char* unknown_chunks_data[3];
+  size_t unknown_chunks_size[3]; /*size in bytes of the unknown chunks, given for protection*/
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} LodePNGInfo;
+
+/*init, cleanup and copy functions to use with this struct*/
+void lodepng_info_init(LodePNGInfo* info);
+void lodepng_info_cleanup(LodePNGInfo* info);
+/*return value is error code (0 means no error)*/
+unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source);
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str); /*push back both texts at once*/
+void lodepng_clear_text(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/
+
+unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag,
+                           const char* transkey, const char* str); /*push back the 4 texts of 1 chunk at once*/
+void lodepng_clear_itext(LodePNGInfo* info); /*use this to clear the itexts again after you filled them in*/
+
+/*replaces if exists*/
+unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size);
+void lodepng_clear_icc(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+/*
+Converts raw buffer from one color type to another color type, based on
+LodePNGColorMode structs to describe the input and output color type.
+See the reference manual at the end of this header file to see which color conversions are supported.
+return value = LodePNG error code (0 if all went ok, an error if the conversion isn't supported)
+The out buffer must have size (w * h * bpp + 7) / 8, where bpp is the bits per pixel
+of the output color type (lodepng_get_bpp).
+For < 8 bpp images, there should not be padding bits at the end of scanlines.
+For 16-bit per channel colors, uses big endian format like PNG does.
+Return value is LodePNG error code
+*/
+unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
+                         const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in,
+                         unsigned w, unsigned h);
+
+#ifdef LODEPNG_COMPILE_DECODER
+/*
+Settings for the decoder. This contains settings for the PNG and the Zlib
+decoder, but not the Info settings from the Info structs.
+*/
+typedef struct LodePNGDecoderSettings {
+  LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/
+
+  /* Check LodePNGDecompressSettings for more ignorable errors such as ignore_adler32 */
+  unsigned ignore_crc; /*ignore CRC checksums*/
+  unsigned ignore_critical; /*ignore unknown critical chunks*/
+  unsigned ignore_end; /*ignore issues at end of file if possible (missing IEND chunk, too large chunk, ...)*/
+  /* TODO: make a system involving warnings with levels and a strict mode instead. Other potentially recoverable
+     errors: srgb rendering intent value, size of content of ancillary chunks, more than 79 characters for some
+     strings, placement/combination rules for ancillary chunks, crc of unknown chunks, allowed characters
+     in string keys, etc... */
+
+  unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+  unsigned read_text_chunks; /*if false but remember_unknown_chunks is true, they're stored in the unknown chunks*/
+  /*store all bytes from unknown chunks in the LodePNGInfo (off by default, useful for a png editor)*/
+  unsigned remember_unknown_chunks;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} LodePNGDecoderSettings;
+
+void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings);
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*automatically use color type with less bits per pixel if losslessly possible. Default: AUTO*/
+typedef enum LodePNGFilterStrategy {
+  /*every filter at zero*/
+  LFS_ZERO,
+  /*Use filter that gives minimum sum, as described in the official PNG filter heuristic.*/
+  LFS_MINSUM,
+  /*Use the filter type that gives smallest Shannon entropy for this scanline. Depending
+  on the image, this is better or worse than minsum.*/
+  LFS_ENTROPY,
+  /*
+  Brute-force-search PNG filters by compressing each filter for each scanline.
+  Experimental, very slow, and only rarely gives better compression than MINSUM.
+  */
+  LFS_BRUTE_FORCE,
+  /*use predefined_filters buffer: you specify the filter type for each scanline*/
+  LFS_PREDEFINED
+} LodePNGFilterStrategy;
+
+/*Gives characteristics about the integer RGBA colors of the image (count, alpha channel usage, bit depth, ...),
+which helps decide which color model to use for encoding.
+Used internally by default if "auto_convert" is enabled. Public because it's useful for custom algorithms.
+NOTE: This is not related to the ICC color profile, search "iccp_profile" instead to find the ICC/chromacity/...
+fields in this header file.*/
+typedef struct LodePNGColorProfile {
+  unsigned colored; /*not grayscale*/
+  unsigned key; /*image is not opaque and color key is possible instead of full alpha*/
+  unsigned short key_r; /*key values, always as 16-bit, in 8-bit case the byte is duplicated, e.g. 65535 means 255*/
+  unsigned short key_g;
+  unsigned short key_b;
+  unsigned alpha; /*image is not opaque and alpha channel or alpha palette required*/
+  unsigned numcolors; /*amount of colors, up to 257. Not valid if bits == 16.*/
+  unsigned char palette[1024]; /*Remembers up to the first 256 RGBA colors, in no particular order*/
+  unsigned bits; /*bits per channel (not for palette). 1,2 or 4 for grayscale only. 16 if 16-bit per channel required.*/
+  size_t numpixels;
+} LodePNGColorProfile;
+
+void lodepng_color_profile_init(LodePNGColorProfile* profile);
+
+/*Get a LodePNGColorProfile of the image. The profile must already have been inited.
+NOTE: This is not related to the ICC color profile, search "iccp_profile" instead to find the ICC/chromacity/...
+fields in this header file.*/
+unsigned lodepng_get_color_profile(LodePNGColorProfile* profile,
+                                   const unsigned char* image, unsigned w, unsigned h,
+                                   const LodePNGColorMode* mode_in);
+/*The function LodePNG uses internally to decide the PNG color with auto_convert.
+Chooses an optimal color model, e.g. gray if only gray pixels, palette if < 256 colors, ...*/
+unsigned lodepng_auto_choose_color(LodePNGColorMode* mode_out,
+                                   const unsigned char* image, unsigned w, unsigned h,
+                                   const LodePNGColorMode* mode_in);
+
+/*Settings for the encoder.*/
+typedef struct LodePNGEncoderSettings {
+  LodePNGCompressSettings zlibsettings; /*settings for the zlib encoder, such as window size, ...*/
+
+  unsigned auto_convert; /*automatically choose output PNG color type. Default: true*/
+
+  /*If true, follows the official PNG heuristic: if the PNG uses a palette or lower than
+  8 bit depth, set all filters to zero. Otherwise use the filter_strategy. Note that to
+  completely follow the official PNG heuristic, filter_palette_zero must be true and
+  filter_strategy must be LFS_MINSUM*/
+  unsigned filter_palette_zero;
+  /*Which filter strategy to use when not using zeroes due to filter_palette_zero.
+  Set filter_palette_zero to 0 to ensure always using your chosen strategy. Default: LFS_MINSUM*/
+  LodePNGFilterStrategy filter_strategy;
+  /*used if filter_strategy is LFS_PREDEFINED. In that case, this must point to a buffer with
+  the same length as the amount of scanlines in the image, and each value must <= 5. You
+  have to cleanup this buffer, LodePNG will never free it. Don't forget that filter_palette_zero
+  must be set to 0 to ensure this is also used on palette or low bitdepth images.*/
+  const unsigned char* predefined_filters;
+
+  /*force creating a PLTE chunk if colortype is 2 or 6 (= a suggested palette).
+  If colortype is 3, PLTE is _always_ created.*/
+  unsigned force_palette;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+  /*add LodePNG identifier and version as a text chunk, for debugging*/
+  unsigned add_id;
+  /*encode text chunks as zTXt chunks instead of tEXt chunks, and use compression in iTXt chunks*/
+  unsigned text_compression;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+} LodePNGEncoderSettings;
+
+void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings);
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+
+#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER)
+/*The settings, state and information for extended encoding and decoding.*/
+typedef struct LodePNGState {
+#ifdef LODEPNG_COMPILE_DECODER
+  LodePNGDecoderSettings decoder; /*the decoding settings*/
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+  LodePNGEncoderSettings encoder; /*the encoding settings*/
+#endif /*LODEPNG_COMPILE_ENCODER*/
+  LodePNGColorMode info_raw; /*specifies the format in which you would like to get the raw pixel buffer*/
+  LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/
+  unsigned error;
+#ifdef LODEPNG_COMPILE_CPP
+  /* For the lodepng::State subclass. */
+  virtual ~LodePNGState(){}
+#endif
+} LodePNGState;
+
+/*init, cleanup and copy functions to use with this struct*/
+void lodepng_state_init(LodePNGState* state);
+void lodepng_state_cleanup(LodePNGState* state);
+void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source);
+#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */
+
+#ifdef LODEPNG_COMPILE_DECODER
+/*
+Same as lodepng_decode_memory, but uses a LodePNGState to allow custom settings and
+getting much more information about the PNG image and color mode.
+*/
+unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h,
+                        LodePNGState* state,
+                        const unsigned char* in, size_t insize);
+
+/*
+Read the PNG header, but not the actual data. This returns only the information
+that is in the IHDR chunk of the PNG, such as width, height and color type. The
+information is placed in the info_png field of the LodePNGState.
+*/
+unsigned lodepng_inspect(unsigned* w, unsigned* h,
+                         LodePNGState* state,
+                         const unsigned char* in, size_t insize);
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+/*
+Reads one metadata chunk (other than IHDR) of the PNG file and outputs what it
+read in the state. Returns error code on failure.
+Use lodepng_inspect first with a new state, then e.g. lodepng_chunk_find_const
+to find the desired chunk type, and if non null use lodepng_inspect_chunk (with
+chunk_pointer - start_of_file as pos).
+Supports most metadata chunks from the PNG standard (gAMA, bKGD, tEXt, ...).
+Ignores unsupported, unknown, non-metadata or IHDR chunks (without error).
+Requirements: &in[pos] must point to start of a chunk, must use regular
+lodepng_inspect first since format of most other chunks depends on IHDR, and if
+there is a PLTE chunk, that one must be inspected before tRNS or bKGD.
+*/
+unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos,
+                               const unsigned char* in, size_t insize);
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*This function allocates the out buffer with standard malloc and stores the size in *outsize.*/
+unsigned lodepng_encode(unsigned char** out, size_t* outsize,
+                        const unsigned char* image, unsigned w, unsigned h,
+                        LodePNGState* state);
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+/*
+The lodepng_chunk functions are normally not needed, except to traverse the
+unknown chunks stored in the LodePNGInfo struct, or add new ones to it.
+It also allows traversing the chunks of an encoded PNG file yourself.
+
+The chunk pointer always points to the beginning of the chunk itself, that is
+the first byte of the 4 length bytes.
+
+In the PNG file format, chunks have the following format:
+-4 bytes length: length of the data of the chunk in bytes (chunk itself is 12 bytes longer)
+-4 bytes chunk type (ASCII a-z,A-Z only, see below)
+-length bytes of data (may be 0 bytes if length was 0)
+-4 bytes of CRC, computed on chunk name + data
+
+The first chunk starts at the 8th byte of the PNG file, the entire rest of the file
+exists out of concatenated chunks with the above format.
+
+PNG standard chunk ASCII naming conventions:
+-First byte: uppercase = critical, lowercase = ancillary
+-Second byte: uppercase = public, lowercase = private
+-Third byte: must be uppercase
+-Fourth byte: uppercase = unsafe to copy, lowercase = safe to copy
+*/
+
+/*
+Gets the length of the data of the chunk. Total chunk length has 12 bytes more.
+There must be at least 4 bytes to read from. If the result value is too large,
+it may be corrupt data.
+*/
+unsigned lodepng_chunk_length(const unsigned char* chunk);
+
+/*puts the 4-byte type in null terminated string*/
+void lodepng_chunk_type(char type[5], const unsigned char* chunk);
+
+/*check if the type is the given type*/
+unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type);
+
+/*0: it's one of the critical chunk types, 1: it's an ancillary chunk (see PNG standard)*/
+unsigned char lodepng_chunk_ancillary(const unsigned char* chunk);
+
+/*0: public, 1: private (see PNG standard)*/
+unsigned char lodepng_chunk_private(const unsigned char* chunk);
+
+/*0: the chunk is unsafe to copy, 1: the chunk is safe to copy (see PNG standard)*/
+unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk);
+
+/*get pointer to the data of the chunk, where the input points to the header of the chunk*/
+unsigned char* lodepng_chunk_data(unsigned char* chunk);
+const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk);
+
+/*returns 0 if the crc is correct, 1 if it's incorrect (0 for OK as usual!)*/
+unsigned lodepng_chunk_check_crc(const unsigned char* chunk);
+
+/*generates the correct CRC from the data and puts it in the last 4 bytes of the chunk*/
+void lodepng_chunk_generate_crc(unsigned char* chunk);
+
+/*
+Iterate to next chunks, allows iterating through all chunks of the PNG file.
+Input must be at the beginning of a chunk (result of a previous lodepng_chunk_next call,
+or the 8th byte of a PNG file which always has the first chunk), or alternatively may
+point to the first byte of the PNG file (which is not a chunk but the magic header, the
+function will then skip over it and return the first real chunk).
+Expects at least 8 readable bytes of memory in the input pointer.
+Will output pointer to the start of the next chunk or the end of the file if there
+is no more chunk after this. Start this process at the 8th byte of the PNG file.
+In a non-corrupt PNG file, the last chunk should have name "IEND".
+*/
+unsigned char* lodepng_chunk_next(unsigned char* chunk);
+const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk);
+
+/*Finds the first chunk with the given type in the range [chunk, end), or returns NULL if not found.*/
+unsigned char* lodepng_chunk_find(unsigned char* chunk, const unsigned char* end, const char type[5]);
+const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]);
+
+/*
+Appends chunk to the data in out. The given chunk should already have its chunk header.
+The out variable and outlength are updated to reflect the new reallocated buffer.
+Returns error code (0 if it went ok)
+*/
+unsigned lodepng_chunk_append(unsigned char** out, size_t* outlength, const unsigned char* chunk);
+
+/*
+Appends new chunk to out. The chunk to append is given by giving its length, type
+and data separately. The type is a 4-letter string.
+The out variable and outlength are updated to reflect the new reallocated buffer.
+Returne error code (0 if it went ok)
+*/
+unsigned lodepng_chunk_create(unsigned char** out, size_t* outlength, unsigned length,
+                              const char* type, const unsigned char* data);
+
+
+/*Calculate CRC32 of buffer*/
+unsigned lodepng_crc32(const unsigned char* buf, size_t len);
+#endif /*LODEPNG_COMPILE_PNG*/
+
+
+#ifdef LODEPNG_COMPILE_ZLIB
+/*
+This zlib part can be used independently to zlib compress and decompress a
+buffer. It cannot be used to create gzip files however, and it only supports the
+part of zlib that is required for PNG, it does not support dictionaries.
+*/
+
+#ifdef LODEPNG_COMPILE_DECODER
+/*Inflate a buffer. Inflate is the decompression step of deflate. Out buffer must be freed after use.*/
+unsigned lodepng_inflate(unsigned char** out, size_t* outsize,
+                         const unsigned char* in, size_t insize,
+                         const LodePNGDecompressSettings* settings);
+
+/*
+Decompresses Zlib data. Reallocates the out buffer and appends the data. The
+data must be according to the zlib specification.
+Either, *out must be NULL and *outsize must be 0, or, *out must be a valid
+buffer and *outsize its size in bytes. out must be freed by user after usage.
+*/
+unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize,
+                                 const unsigned char* in, size_t insize,
+                                 const LodePNGDecompressSettings* settings);
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*
+Compresses data with Zlib. Reallocates the out buffer and appends the data.
+Zlib adds a small header and trailer around the deflate data.
+The data is output in the format of the zlib specification.
+Either, *out must be NULL and *outsize must be 0, or, *out must be a valid
+buffer and *outsize its size in bytes. out must be freed by user after usage.
+*/
+unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize,
+                               const unsigned char* in, size_t insize,
+                               const LodePNGCompressSettings* settings);
+
+/*
+Find length-limited Huffman code for given frequencies. This function is in the
+public interface only for tests, it's used internally by lodepng_deflate.
+*/
+unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies,
+                                      size_t numcodes, unsigned maxbitlen);
+
+/*Compress a buffer with deflate. See RFC 1951. Out buffer must be freed after use.*/
+unsigned lodepng_deflate(unsigned char** out, size_t* outsize,
+                         const unsigned char* in, size_t insize,
+                         const LodePNGCompressSettings* settings);
+
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#endif /*LODEPNG_COMPILE_ZLIB*/
+
+#ifdef LODEPNG_COMPILE_DISK
+/*
+Load a file from disk into buffer. The function allocates the out buffer, and
+after usage you should free it.
+out: output parameter, contains pointer to loaded buffer.
+outsize: output parameter, size of the allocated out buffer
+filename: the path to the file to load
+return value: error code (0 means ok)
+*/
+unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename);
+
+/*
+Save a file from buffer to disk. Warning, if it exists, this function overwrites
+the file without warning!
+buffer: the buffer to write
+buffersize: size of the buffer to write
+filename: the path to the file to save to
+return value: error code (0 means ok)
+*/
+unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename);
+#endif /*LODEPNG_COMPILE_DISK*/
+
+#ifdef LODEPNG_COMPILE_CPP
+/* The LodePNG C++ wrapper uses std::vectors instead of manually allocated memory buffers. */
+namespace lodepng {
+#ifdef LODEPNG_COMPILE_PNG
+class State : public LodePNGState {
+  public:
+    State();
+    State(const State& other);
+    virtual ~State();
+    State& operator=(const State& other);
+};
+
+#ifdef LODEPNG_COMPILE_DECODER
+/* Same as other lodepng::decode, but using a State for more settings and information. */
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+                State& state,
+                const unsigned char* in, size_t insize);
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+                State& state,
+                const std::vector<unsigned char>& in);
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/* Same as other lodepng::encode, but using a State for more settings and information. */
+unsigned encode(std::vector<unsigned char>& out,
+                const unsigned char* in, unsigned w, unsigned h,
+                State& state);
+unsigned encode(std::vector<unsigned char>& out,
+                const std::vector<unsigned char>& in, unsigned w, unsigned h,
+                State& state);
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+#ifdef LODEPNG_COMPILE_DISK
+/*
+Load a file from disk into an std::vector.
+return value: error code (0 means ok)
+*/
+unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename);
+
+/*
+Save the binary data in an std::vector to a file on disk. The file is overwritten
+without warning.
+*/
+unsigned save_file(const std::vector<unsigned char>& buffer, const std::string& filename);
+#endif /* LODEPNG_COMPILE_DISK */
+#endif /* LODEPNG_COMPILE_PNG */
+
+#ifdef LODEPNG_COMPILE_ZLIB
+#ifdef LODEPNG_COMPILE_DECODER
+/* Zlib-decompress an unsigned char buffer */
+unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
+                    const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings);
+
+/* Zlib-decompress an std::vector */
+unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
+                    const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings);
+#endif /* LODEPNG_COMPILE_DECODER */
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/* Zlib-compress an unsigned char buffer */
+unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
+                  const LodePNGCompressSettings& settings = lodepng_default_compress_settings);
+
+/* Zlib-compress an std::vector */
+unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
+                  const LodePNGCompressSettings& settings = lodepng_default_compress_settings);
+#endif /* LODEPNG_COMPILE_ENCODER */
+#endif /* LODEPNG_COMPILE_ZLIB */
+} /* namespace lodepng */
+#endif /*LODEPNG_COMPILE_CPP*/
+
+/*
+TODO:
+[.] test if there are no memory leaks or security exploits - done a lot but needs to be checked often
+[.] check compatibility with various compilers  - done but needs to be redone for every newer version
+[X] converting color to 16-bit per channel types
+[X] support color profile chunk types (but never let them touch RGB values by default)
+[ ] support all public PNG chunk types (almost done except sBIT, sPLT and hIST)
+[ ] make sure encoder generates no chunks with size > (2^31)-1
+[ ] partial decoding (stream processing)
+[X] let the "isFullyOpaque" function check color keys and transparent palettes too
+[X] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl"
+[ ] allow treating some errors like warnings, when image is recoverable (e.g. 69, 57, 58)
+[ ] make warnings like: oob palette, checksum fail, data after iend, wrong/unknown crit chunk, no null terminator in text, ...
+[ ] error messages with line numbers (and version)
+[ ] errors in state instead of as return code?
+[ ] new errors/warnings like suspiciously big decompressed ztxt or iccp chunk
+[ ] let the C++ wrapper catch exceptions coming from the standard library and return LodePNG error codes
+[ ] allow user to provide custom color conversion functions, e.g. for premultiplied alpha, padding bits or not, ...
+[ ] allow user to give data (void*) to custom allocator
+[ ] provide alternatives for C library functions not present on some platforms (memcpy, ...)
+[ ] rename "grey" to "gray" everywhere since "color" also uses US spelling (keep "grey" copies for backwards compatibility)
+*/
+
+#endif /*LODEPNG_H inclusion guard*/
+
+/*
+LodePNG Documentation
+---------------------
+
+0. table of contents
+--------------------
+
+  1. about
+   1.1. supported features
+   1.2. features not supported
+  2. C and C++ version
+  3. security
+  4. decoding
+  5. encoding
+  6. color conversions
+    6.1. PNG color types
+    6.2. color conversions
+    6.3. padding bits
+    6.4. A note about 16-bits per channel and endianness
+  7. error values
+  8. chunks and PNG editing
+  9. compiler support
+  10. examples
+   10.1. decoder C++ example
+   10.2. decoder C example
+  11. state settings reference
+  12. changes
+  13. contact information
+
+
+1. about
+--------
+
+PNG is a file format to store raster images losslessly with good compression,
+supporting different color types and alpha channel.
+
+LodePNG is a PNG codec according to the Portable Network Graphics (PNG)
+Specification (Second Edition) - W3C Recommendation 10 November 2003.
+
+The specifications used are:
+
+*) Portable Network Graphics (PNG) Specification (Second Edition):
+     http://www.w3.org/TR/2003/REC-PNG-20031110
+*) RFC 1950 ZLIB Compressed Data Format version 3.3:
+     http://www.gzip.org/zlib/rfc-zlib.html
+*) RFC 1951 DEFLATE Compressed Data Format Specification ver 1.3:
+     http://www.gzip.org/zlib/rfc-deflate.html
+
+The most recent version of LodePNG can currently be found at
+http://lodev.org/lodepng/
+
+LodePNG works both in C (ISO C90) and C++, with a C++ wrapper that adds
+extra functionality.
+
+LodePNG exists out of two files:
+-lodepng.h: the header file for both C and C++
+-lodepng.c(pp): give it the name lodepng.c or lodepng.cpp (or .cc) depending on your usage
+
+If you want to start using LodePNG right away without reading this doc, get the
+examples from the LodePNG website to see how to use it in code, or check the
+smaller examples in chapter 13 here.
+
+LodePNG is simple but only supports the basic requirements. To achieve
+simplicity, the following design choices were made: There are no dependencies
+on any external library. There are functions to decode and encode a PNG with
+a single function call, and extended versions of these functions taking a
+LodePNGState struct allowing to specify or get more information. By default
+the colors of the raw image are always RGB or RGBA, no matter what color type
+the PNG file uses. To read and write files, there are simple functions to
+convert the files to/from buffers in memory.
+
+This all makes LodePNG suitable for loading textures in games, demos and small
+programs, ... It's less suitable for full fledged image editors, loading PNGs
+over network (it requires all the image data to be available before decoding can
+begin), life-critical systems, ...
+
+1.1. supported features
+-----------------------
+
+The following features are supported by the decoder:
+
+*) decoding of PNGs with any color type, bit depth and interlace mode, to a 24- or 32-bit color raw image,
+   or the same color type as the PNG
+*) encoding of PNGs, from any raw image to 24- or 32-bit color, or the same color type as the raw image
+*) Adam7 interlace and deinterlace for any color type
+*) loading the image from harddisk or decoding it from a buffer from other sources than harddisk
+*) support for alpha channels, including RGBA color model, translucent palettes and color keying
+*) zlib decompression (inflate)
+*) zlib compression (deflate)
+*) CRC32 and ADLER32 checksums
+*) colorimetric color profile conversions: currently experimentally available in lodepng_util.cpp only,
+   plus alternatively ability to pass on chroma/gamma/ICC profile information to other color management system.
+*) handling of unknown chunks, allowing making a PNG editor that stores custom and unknown chunks.
+*) the following chunks are supported by both encoder and decoder:
+    IHDR: header information
+    PLTE: color palette
+    IDAT: pixel data
+    IEND: the final chunk
+    tRNS: transparency for palettized images
+    tEXt: textual information
+    zTXt: compressed textual information
+    iTXt: international textual information
+    bKGD: suggested background color
+    pHYs: physical dimensions
+    tIME: modification time
+    cHRM: RGB chromaticities
+    gAMA: RGB gamma correction
+    iCCP: ICC color profile
+    sRGB: rendering intent
+
+1.2. features not supported
+---------------------------
+
+The following features are _not_ supported:
+
+*) some features needed to make a conformant PNG-Editor might be still missing.
+*) partial loading/stream processing. All data must be available and is processed in one call.
+*) The following public chunks are not (yet) supported but treated as unknown chunks by LodePNG:
+    sBIT
+    hIST
+    sPLT
+
+
+2. C and C++ version
+--------------------
+
+The C version uses buffers allocated with alloc that you need to free()
+yourself. You need to use init and cleanup functions for each struct whenever
+using a struct from the C version to avoid exploits and memory leaks.
+
+The C++ version has extra functions with std::vectors in the interface and the
+lodepng::State class which is a LodePNGState with constructor and destructor.
+
+These files work without modification for both C and C++ compilers because all
+the additional C++ code is in "#ifdef __cplusplus" blocks that make C-compilers
+ignore it, and the C code is made to compile both with strict ISO C90 and C++.
+
+To use the C++ version, you need to rename the source file to lodepng.cpp
+(instead of lodepng.c), and compile it with a C++ compiler.
+
+To use the C version, you need to rename the source file to lodepng.c (instead
+of lodepng.cpp), and compile it with a C compiler.
+
+
+3. Security
+-----------
+
+Even if carefully designed, it's always possible that LodePNG contains possible
+exploits. If you discover one, please let me know, and it will be fixed.
+
+When using LodePNG, care has to be taken with the C version of LodePNG, as well
+as the C-style structs when working with C++. The following conventions are used
+for all C-style structs:
+
+-if a struct has a corresponding init function, always call the init function when making a new one
+-if a struct has a corresponding cleanup function, call it before the struct disappears to avoid memory leaks
+-if a struct has a corresponding copy function, use the copy function instead of "=".
+ The destination must also be inited already.
+
+
+4. Decoding
+-----------
+
+Decoding converts a PNG compressed image to a raw pixel buffer.
+
+Most documentation on using the decoder is at its declarations in the header
+above. For C, simple decoding can be done with functions such as
+lodepng_decode32, and more advanced decoding can be done with the struct
+LodePNGState and lodepng_decode. For C++, all decoding can be done with the
+various lodepng::decode functions, and lodepng::State can be used for advanced
+features.
+
+When using the LodePNGState, it uses the following fields for decoding:
+*) LodePNGInfo info_png: it stores extra information about the PNG (the input) in here
+*) LodePNGColorMode info_raw: here you can say what color mode of the raw image (the output) you want to get
+*) LodePNGDecoderSettings decoder: you can specify a few extra settings for the decoder to use
+
+LodePNGInfo info_png
+--------------------
+
+After decoding, this contains extra information of the PNG image, except the actual
+pixels, width and height because these are already gotten directly from the decoder
+functions.
+
+It contains for example the original color type of the PNG image, text comments,
+suggested background color, etc... More details about the LodePNGInfo struct are
+at its declaration documentation.
+
+LodePNGColorMode info_raw
+-------------------------
+
+When decoding, here you can specify which color type you want
+the resulting raw image to be. If this is different from the colortype of the
+PNG, then the decoder will automatically convert the result. This conversion
+always works, except if you want it to convert a color PNG to grayscale or to
+a palette with missing colors.
+
+By default, 32-bit color is used for the result.
+
+LodePNGDecoderSettings decoder
+------------------------------
+
+The settings can be used to ignore the errors created by invalid CRC and Adler32
+chunks, and to disable the decoding of tEXt chunks.
+
+There's also a setting color_convert, true by default. If false, no conversion
+is done, the resulting data will be as it was in the PNG (after decompression)
+and you'll have to puzzle the colors of the pixels together yourself using the
+color type information in the LodePNGInfo.
+
+
+5. Encoding
+-----------
+
+Encoding converts a raw pixel buffer to a PNG compressed image.
+
+Most documentation on using the encoder is at its declarations in the header
+above. For C, simple encoding can be done with functions such as
+lodepng_encode32, and more advanced decoding can be done with the struct
+LodePNGState and lodepng_encode. For C++, all encoding can be done with the
+various lodepng::encode functions, and lodepng::State can be used for advanced
+features.
+
+Like the decoder, the encoder can also give errors. However it gives less errors
+since the encoder input is trusted, the decoder input (a PNG image that could
+be forged by anyone) is not trusted.
+
+When using the LodePNGState, it uses the following fields for encoding:
+*) LodePNGInfo info_png: here you specify how you want the PNG (the output) to be.
+*) LodePNGColorMode info_raw: here you say what color type of the raw image (the input) has
+*) LodePNGEncoderSettings encoder: you can specify a few settings for the encoder to use
+
+LodePNGInfo info_png
+--------------------
+
+When encoding, you use this the opposite way as when decoding: for encoding,
+you fill in the values you want the PNG to have before encoding. By default it's
+not needed to specify a color type for the PNG since it's automatically chosen,
+but it's possible to choose it yourself given the right settings.
+
+The encoder will not always exactly match the LodePNGInfo struct you give,
+it tries as close as possible. Some things are ignored by the encoder. The
+encoder uses, for example, the following settings from it when applicable:
+colortype and bitdepth, text chunks, time chunk, the color key, the palette, the
+background color, the interlace method, unknown chunks, ...
+
+When encoding to a PNG with colortype 3, the encoder will generate a PLTE chunk.
+If the palette contains any colors for which the alpha channel is not 255 (so
+there are translucent colors in the palette), it'll add a tRNS chunk.
+
+LodePNGColorMode info_raw
+-------------------------
+
+You specify the color type of the raw image that you give to the input here,
+including a possible transparent color key and palette you happen to be using in
+your raw image data.
+
+By default, 32-bit color is assumed, meaning your input has to be in RGBA
+format with 4 bytes (unsigned chars) per pixel.
+
+LodePNGEncoderSettings encoder
+------------------------------
+
+The following settings are supported (some are in sub-structs):
+*) auto_convert: when this option is enabled, the encoder will
+automatically choose the smallest possible color mode (including color key) that
+can encode the colors of all pixels without information loss.
+*) btype: the block type for LZ77. 0 = uncompressed, 1 = fixed huffman tree,
+   2 = dynamic huffman tree (best compression). Should be 2 for proper
+   compression.
+*) use_lz77: whether or not to use LZ77 for compressed block types. Should be
+   true for proper compression.
+*) windowsize: the window size used by the LZ77 encoder (1 - 32768). Has value
+   2048 by default, but can be set to 32768 for better, but slow, compression.
+*) force_palette: if colortype is 2 or 6, you can make the encoder write a PLTE
+   chunk if force_palette is true. This can used as suggested palette to convert
+   to by viewers that don't support more than 256 colors (if those still exist)
+*) add_id: add text chunk "Encoder: LodePNG <version>" to the image.
+*) text_compression: default 1. If 1, it'll store texts as zTXt instead of tEXt chunks.
+  zTXt chunks use zlib compression on the text. This gives a smaller result on
+  large texts but a larger result on small texts (such as a single program name).
+  It's all tEXt or all zTXt though, there's no separate setting per text yet.
+
+
+6. color conversions
+--------------------
+
+An important thing to note about LodePNG, is that the color type of the PNG, and
+the color type of the raw image, are completely independent. By default, when
+you decode a PNG, you get the result as a raw image in the color type you want,
+no matter whether the PNG was encoded with a palette, grayscale or RGBA color.
+And if you encode an image, by default LodePNG will automatically choose the PNG
+color type that gives good compression based on the values of colors and amount
+of colors in the image. It can be configured to let you control it instead as
+well, though.
+
+To be able to do this, LodePNG does conversions from one color mode to another.
+It can convert from almost any color type to any other color type, except the
+following conversions: RGB to grayscale is not supported, and converting to a
+palette when the palette doesn't have a required color is not supported. This is
+not supported on purpose: this is information loss which requires a color
+reduction algorithm that is beyong the scope of a PNG encoder (yes, RGB to gray
+is easy, but there are multiple ways if you want to give some channels more
+weight).
+
+By default, when decoding, you get the raw image in 32-bit RGBA or 24-bit RGB
+color, no matter what color type the PNG has. And by default when encoding,
+LodePNG automatically picks the best color model for the output PNG, and expects
+the input image to be 32-bit RGBA or 24-bit RGB. So, unless you want to control
+the color format of the images yourself, you can skip this chapter.
+
+6.1. PNG color types
+--------------------
+
+A PNG image can have many color types, ranging from 1-bit color to 64-bit color,
+as well as palettized color modes. After the zlib decompression and unfiltering
+in the PNG image is done, the raw pixel data will have that color type and thus
+a certain amount of bits per pixel. If you want the output raw image after
+decoding to have another color type, a conversion is done by LodePNG.
+
+The PNG specification gives the following color types:
+
+0: grayscale, bit depths 1, 2, 4, 8, 16
+2: RGB, bit depths 8 and 16
+3: palette, bit depths 1, 2, 4 and 8
+4: grayscale with alpha, bit depths 8 and 16
+6: RGBA, bit depths 8 and 16
+
+Bit depth is the amount of bits per pixel per color channel. So the total amount
+of bits per pixel is: amount of channels * bitdepth.
+
+6.2. color conversions
+----------------------
+
+As explained in the sections about the encoder and decoder, you can specify
+color types and bit depths in info_png and info_raw to change the default
+behaviour.
+
+If, when decoding, you want the raw image to be something else than the default,
+you need to set the color type and bit depth you want in the LodePNGColorMode,
+or the parameters colortype and bitdepth of the simple decoding function.
+
+If, when encoding, you use another color type than the default in the raw input
+image, you need to specify its color type and bit depth in the LodePNGColorMode
+of the raw image, or use the parameters colortype and bitdepth of the simple
+encoding function.
+
+If, when encoding, you don't want LodePNG to choose the output PNG color type
+but control it yourself, you need to set auto_convert in the encoder settings
+to false, and specify the color type you want in the LodePNGInfo of the
+encoder (including palette: it can generate a palette if auto_convert is true,
+otherwise not).
+
+If the input and output color type differ (whether user chosen or auto chosen),
+LodePNG will do a color conversion, which follows the rules below, and may
+sometimes result in an error.
+
+To avoid some confusion:
+-the decoder converts from PNG to raw image
+-the encoder converts from raw image to PNG
+-the colortype and bitdepth in LodePNGColorMode info_raw, are those of the raw image
+-the colortype and bitdepth in the color field of LodePNGInfo info_png, are those of the PNG
+-when encoding, the color type in LodePNGInfo is ignored if auto_convert
+ is enabled, it is automatically generated instead
+-when decoding, the color type in LodePNGInfo is set by the decoder to that of the original
+ PNG image, but it can be ignored since the raw image has the color type you requested instead
+-if the color type of the LodePNGColorMode and PNG image aren't the same, a conversion
+ between the color types is done if the color types are supported. If it is not
+ supported, an error is returned. If the types are the same, no conversion is done.
+-even though some conversions aren't supported, LodePNG supports loading PNGs from any
+ colortype and saving PNGs to any colortype, sometimes it just requires preparing
+ the raw image correctly before encoding.
+-both encoder and decoder use the same color converter.
+
+The function lodepng_convert does the color conversion. It is available in the
+interface but normally isn't needed since the encoder and decoder already call
+it.
+
+Non supported color conversions:
+-color to grayscale when non-gray pixels are present: no error is thrown, but
+the result will look ugly because only the red channel is taken (it assumes all
+three channels are the same in this case so ignores green and blue). The reason
+no error is given is to allow converting from three-channel grayscale images to
+one-channel even if there are numerical imprecisions.
+-anything to palette when the palette does not have an exact match for a from-color
+in it: in this case an error is thrown
+
+Supported color conversions:
+-anything to 8-bit RGB, 8-bit RGBA, 16-bit RGB, 16-bit RGBA
+-any gray or gray+alpha, to gray or gray+alpha
+-anything to a palette, as long as the palette has the requested colors in it
+-removing alpha channel
+-higher to smaller bitdepth, and vice versa
+
+If you want no color conversion to be done (e.g. for speed or control):
+-In the encoder, you can make it save a PNG with any color type by giving the
+raw color mode and LodePNGInfo the same color mode, and setting auto_convert to
+false.
+-In the decoder, you can make it store the pixel data in the same color type
+as the PNG has, by setting the color_convert setting to false. Settings in
+info_raw are then ignored.
+
+6.3. padding bits
+-----------------
+
+In the PNG file format, if a less than 8-bit per pixel color type is used and the scanlines
+have a bit amount that isn't a multiple of 8, then padding bits are used so that each
+scanline starts at a fresh byte. But that is NOT true for the LodePNG raw input and output.
+The raw input image you give to the encoder, and the raw output image you get from the decoder
+will NOT have these padding bits, e.g. in the case of a 1-bit image with a width
+of 7 pixels, the first pixel of the second scanline will the the 8th bit of the first byte,
+not the first bit of a new byte.
+
+6.4. A note about 16-bits per channel and endianness
+----------------------------------------------------
+
+LodePNG uses unsigned char arrays for 16-bit per channel colors too, just like
+for any other color format. The 16-bit values are stored in big endian (most
+significant byte first) in these arrays. This is the opposite order of the
+little endian used by x86 CPU's.
+
+LodePNG always uses big endian because the PNG file format does so internally.
+Conversions to other formats than PNG uses internally are not supported by
+LodePNG on purpose, there are myriads of formats, including endianness of 16-bit
+colors, the order in which you store R, G, B and A, and so on. Supporting and
+converting to/from all that is outside the scope of LodePNG.
+
+This may mean that, depending on your use case, you may want to convert the big
+endian output of LodePNG to little endian with a for loop. This is certainly not
+always needed, many applications and libraries support big endian 16-bit colors
+anyway, but it means you cannot simply cast the unsigned char* buffer to an
+unsigned short* buffer on x86 CPUs.
+
+
+7. error values
+---------------
+
+All functions in LodePNG that return an error code, return 0 if everything went
+OK, or a non-zero code if there was an error.
+
+The meaning of the LodePNG error values can be retrieved with the function
+lodepng_error_text: given the numerical error code, it returns a description
+of the error in English as a string.
+
+Check the implementation of lodepng_error_text to see the meaning of each code.
+
+
+8. chunks and PNG editing
+-------------------------
+
+If you want to add extra chunks to a PNG you encode, or use LodePNG for a PNG
+editor that should follow the rules about handling of unknown chunks, or if your
+program is able to read other types of chunks than the ones handled by LodePNG,
+then that's possible with the chunk functions of LodePNG.
+
+A PNG chunk has the following layout:
+
+4 bytes length
+4 bytes type name
+length bytes data
+4 bytes CRC
+
+8.1. iterating through chunks
+-----------------------------
+
+If you have a buffer containing the PNG image data, then the first chunk (the
+IHDR chunk) starts at byte number 8 of that buffer. The first 8 bytes are the
+signature of the PNG and are not part of a chunk. But if you start at byte 8
+then you have a chunk, and can check the following things of it.
+
+NOTE: none of these functions check for memory buffer boundaries. To avoid
+exploits, always make sure the buffer contains all the data of the chunks.
+When using lodepng_chunk_next, make sure the returned value is within the
+allocated memory.
+
+unsigned lodepng_chunk_length(const unsigned char* chunk):
+
+Get the length of the chunk's data. The total chunk length is this length + 12.
+
+void lodepng_chunk_type(char type[5], const unsigned char* chunk):
+unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type):
+
+Get the type of the chunk or compare if it's a certain type
+
+unsigned char lodepng_chunk_critical(const unsigned char* chunk):
+unsigned char lodepng_chunk_private(const unsigned char* chunk):
+unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk):
+
+Check if the chunk is critical in the PNG standard (only IHDR, PLTE, IDAT and IEND are).
+Check if the chunk is private (public chunks are part of the standard, private ones not).
+Check if the chunk is safe to copy. If it's not, then, when modifying data in a critical
+chunk, unsafe to copy chunks of the old image may NOT be saved in the new one if your
+program doesn't handle that type of unknown chunk.
+
+unsigned char* lodepng_chunk_data(unsigned char* chunk):
+const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk):
+
+Get a pointer to the start of the data of the chunk.
+
+unsigned lodepng_chunk_check_crc(const unsigned char* chunk):
+void lodepng_chunk_generate_crc(unsigned char* chunk):
+
+Check if the crc is correct or generate a correct one.
+
+unsigned char* lodepng_chunk_next(unsigned char* chunk):
+const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk):
+
+Iterate to the next chunk. This works if you have a buffer with consecutive chunks. Note that these
+functions do no boundary checking of the allocated data whatsoever, so make sure there is enough
+data available in the buffer to be able to go to the next chunk.
+
+unsigned lodepng_chunk_append(unsigned char** out, size_t* outlength, const unsigned char* chunk):
+unsigned lodepng_chunk_create(unsigned char** out, size_t* outlength, unsigned length,
+                              const char* type, const unsigned char* data):
+
+These functions are used to create new chunks that are appended to the data in *out that has
+length *outlength. The append function appends an existing chunk to the new data. The create
+function creates a new chunk with the given parameters and appends it. Type is the 4-letter
+name of the chunk.
+
+8.2. chunks in info_png
+-----------------------
+
+The LodePNGInfo struct contains fields with the unknown chunk in it. It has 3
+buffers (each with size) to contain 3 types of unknown chunks:
+the ones that come before the PLTE chunk, the ones that come between the PLTE
+and the IDAT chunks, and the ones that come after the IDAT chunks.
+It's necessary to make the distionction between these 3 cases because the PNG
+standard forces to keep the ordering of unknown chunks compared to the critical
+chunks, but does not force any other ordering rules.
+
+info_png.unknown_chunks_data[0] is the chunks before PLTE
+info_png.unknown_chunks_data[1] is the chunks after PLTE, before IDAT
+info_png.unknown_chunks_data[2] is the chunks after IDAT
+
+The chunks in these 3 buffers can be iterated through and read by using the same
+way described in the previous subchapter.
+
+When using the decoder to decode a PNG, you can make it store all unknown chunks
+if you set the option settings.remember_unknown_chunks to 1. By default, this
+option is off (0).
+
+The encoder will always encode unknown chunks that are stored in the info_png.
+If you need it to add a particular chunk that isn't known by LodePNG, you can
+use lodepng_chunk_append or lodepng_chunk_create to the chunk data in
+info_png.unknown_chunks_data[x].
+
+Chunks that are known by LodePNG should not be added in that way. E.g. to make
+LodePNG add a bKGD chunk, set background_defined to true and add the correct
+parameters there instead.
+
+
+9. compiler support
+-------------------
+
+No libraries other than the current standard C library are needed to compile
+LodePNG. For the C++ version, only the standard C++ library is needed on top.
+Add the files lodepng.c(pp) and lodepng.h to your project, include
+lodepng.h where needed, and your program can read/write PNG files.
+
+It is compatible with C90 and up, and C++03 and up.
+
+If performance is important, use optimization when compiling! For both the
+encoder and decoder, this makes a large difference.
+
+Make sure that LodePNG is compiled with the same compiler of the same version
+and with the same settings as the rest of the program, or the interfaces with
+std::vectors and std::strings in C++ can be incompatible.
+
+CHAR_BITS must be 8 or higher, because LodePNG uses unsigned chars for octets.
+
+*) gcc and g++
+
+LodePNG is developed in gcc so this compiler is natively supported. It gives no
+warnings with compiler options "-Wall -Wextra -pedantic -ansi", with gcc and g++
+version 4.7.1 on Linux, 32-bit and 64-bit.
+
+*) Clang
+
+Fully supported and warning-free.
+
+*) Mingw
+
+The Mingw compiler (a port of gcc for Windows) should be fully supported by
+LodePNG.
+
+*) Visual Studio and Visual C++ Express Edition
+
+LodePNG should be warning-free with warning level W4. Two warnings were disabled
+with pragmas though: warning 4244 about implicit conversions, and warning 4996
+where it wants to use a non-standard function fopen_s instead of the standard C
+fopen.
+
+Visual Studio may want "stdafx.h" files to be included in each source file and
+give an error "unexpected end of file while looking for precompiled header".
+This is not standard C++ and will not be added to the stock LodePNG. You can
+disable it for lodepng.cpp only by right clicking it, Properties, C/C++,
+Precompiled Headers, and set it to Not Using Precompiled Headers there.
+
+NOTE: Modern versions of VS should be fully supported, but old versions, e.g.
+VS6, are not guaranteed to work.
+
+*) Compilers on Macintosh
+
+LodePNG has been reported to work both with gcc and LLVM for Macintosh, both for
+C and C++.
+
+*) Other Compilers
+
+If you encounter problems on any compilers, feel free to let me know and I may
+try to fix it if the compiler is modern and standards complient.
+
+
+10. examples
+------------
+
+This decoder example shows the most basic usage of LodePNG. More complex
+examples can be found on the LodePNG website.
+
+10.1. decoder C++ example
+-------------------------
+
+#include "lodepng.h"
+#include <iostream>
+
+int main(int argc, char *argv[]) {
+  const char* filename = argc > 1 ? argv[1] : "test.png";
+
+  //load and decode
+  std::vector<unsigned char> image;
+  unsigned width, height;
+  unsigned error = lodepng::decode(image, width, height, filename);
+
+  //if there's an error, display it
+  if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+
+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
+}
+
+10.2. decoder C example
+-----------------------
+
+#include "lodepng.h"
+
+int main(int argc, char *argv[]) {
+  unsigned error;
+  unsigned char* image;
+  size_t width, height;
+  const char* filename = argc > 1 ? argv[1] : "test.png";
+
+  error = lodepng_decode32_file(&image, &width, &height, filename);
+
+  if(error) printf("decoder error %u: %s\n", error, lodepng_error_text(error));
+
+  / * use image here * /
+
+  free(image);
+  return 0;
+}
+
+11. state settings reference
+----------------------------
+
+A quick reference of some settings to set on the LodePNGState
+
+For decoding:
+
+state.decoder.zlibsettings.ignore_adler32: ignore ADLER32 checksums
+state.decoder.zlibsettings.custom_...: use custom inflate function
+state.decoder.ignore_crc: ignore CRC checksums
+state.decoder.ignore_critical: ignore unknown critical chunks
+state.decoder.ignore_end: ignore missing IEND chunk. May fail if this corruption causes other errors
+state.decoder.color_convert: convert internal PNG color to chosen one
+state.decoder.read_text_chunks: whether to read in text metadata chunks
+state.decoder.remember_unknown_chunks: whether to read in unknown chunks
+state.info_raw.colortype: desired color type for decoded image
+state.info_raw.bitdepth: desired bit depth for decoded image
+state.info_raw....: more color settings, see struct LodePNGColorMode
+state.info_png....: no settings for decoder but ouput, see struct LodePNGInfo
+
+For encoding:
+
+state.encoder.zlibsettings.btype: disable compression by setting it to 0
+state.encoder.zlibsettings.use_lz77: use LZ77 in compression
+state.encoder.zlibsettings.windowsize: tweak LZ77 windowsize
+state.encoder.zlibsettings.minmatch: tweak min LZ77 length to match
+state.encoder.zlibsettings.nicematch: tweak LZ77 match where to stop searching
+state.encoder.zlibsettings.lazymatching: try one more LZ77 matching
+state.encoder.zlibsettings.custom_...: use custom deflate function
+state.encoder.auto_convert: choose optimal PNG color type, if 0 uses info_png
+state.encoder.filter_palette_zero: PNG filter strategy for palette
+state.encoder.filter_strategy: PNG filter strategy to encode with
+state.encoder.force_palette: add palette even if not encoding to one
+state.encoder.add_id: add LodePNG identifier and version as a text chunk
+state.encoder.text_compression: use compressed text chunks for metadata
+state.info_raw.colortype: color type of raw input image you provide
+state.info_raw.bitdepth: bit depth of raw input image you provide
+state.info_raw: more color settings, see struct LodePNGColorMode
+state.info_png.color.colortype: desired color type if auto_convert is false
+state.info_png.color.bitdepth: desired bit depth if auto_convert is false
+state.info_png.color....: more color settings, see struct LodePNGColorMode
+state.info_png....: more PNG related settings, see struct LodePNGInfo
+
+
+12. changes
+-----------
+
+The version number of LodePNG is the date of the change given in the format
+yyyymmdd.
+
+Some changes aren't backwards compatible. Those are indicated with a (!)
+symbol.
+
+*) 30 dec 2018: code style changes only: removed newlines before opening braces.
+*) 10 sep 2018: added way to inspect metadata chunks without full decoding.
+*) 19 aug 2018 (!): fixed color mode bKGD is encoded with and made it use
+   palette index in case of palette.
+*) 10 aug 2018 (!): added support for gAMA, cHRM, sRGB and iCCP chunks. This
+   change is backwards compatible unless you relied on unknown_chunks for those.
+*) 11 jun 2018: less restrictive check for pixel size integer overflow
+*) 14 jan 2018: allow optionally ignoring a few more recoverable errors
+*) 17 sep 2017: fix memory leak for some encoder input error cases
+*) 27 nov 2016: grey+alpha auto color model detection bugfix
+*) 18 apr 2016: Changed qsort to custom stable sort (for platforms w/o qsort).
+*) 09 apr 2016: Fixed colorkey usage detection, and better file loading (within
+   the limits of pure C90).
+*) 08 dec 2015: Made load_file function return error if file can't be opened.
+*) 24 okt 2015: Bugfix with decoding to palette output.
+*) 18 apr 2015: Boundary PM instead of just package-merge for faster encoding.
+*) 23 aug 2014: Reduced needless memory usage of decoder.
+*) 28 jun 2014: Removed fix_png setting, always support palette OOB for
+    simplicity. Made ColorProfile public.
+*) 09 jun 2014: Faster encoder by fixing hash bug and more zeros optimization.
+*) 22 dec 2013: Power of two windowsize required for optimization.
+*) 15 apr 2013: Fixed bug with LAC_ALPHA and color key.
+*) 25 mar 2013: Added an optional feature to ignore some PNG errors (fix_png).
+*) 11 mar 2013 (!): Bugfix with custom free. Changed from "my" to "lodepng_"
+    prefix for the custom allocators and made it possible with a new #define to
+    use custom ones in your project without needing to change lodepng's code.
+*) 28 jan 2013: Bugfix with color key.
+*) 27 okt 2012: Tweaks in text chunk keyword length error handling.
+*) 8 okt 2012 (!): Added new filter strategy (entropy) and new auto color mode.
+    (no palette). Better deflate tree encoding. New compression tweak settings.
+    Faster color conversions while decoding. Some internal cleanups.
+*) 23 sep 2012: Reduced warnings in Visual Studio a little bit.
+*) 1 sep 2012 (!): Removed #define's for giving custom (de)compression functions
+    and made it work with function pointers instead.
+*) 23 jun 2012: Added more filter strategies. Made it easier to use custom alloc
+    and free functions and toggle #defines from compiler flags. Small fixes.
+*) 6 may 2012 (!): Made plugging in custom zlib/deflate functions more flexible.
+*) 22 apr 2012 (!): Made interface more consistent, renaming a lot. Removed
+    redundant C++ codec classes. Reduced amount of structs. Everything changed,
+    but it is cleaner now imho and functionality remains the same. Also fixed
+    several bugs and shrunk the implementation code. Made new samples.
+*) 6 nov 2011 (!): By default, the encoder now automatically chooses the best
+    PNG color model and bit depth, based on the amount and type of colors of the
+    raw image. For this, autoLeaveOutAlphaChannel replaced by auto_choose_color.
+*) 9 okt 2011: simpler hash chain implementation for the encoder.
+*) 8 sep 2011: lz77 encoder lazy matching instead of greedy matching.
+*) 23 aug 2011: tweaked the zlib compression parameters after benchmarking.
+    A bug with the PNG filtertype heuristic was fixed, so that it chooses much
+    better ones (it's quite significant). A setting to do an experimental, slow,
+    brute force search for PNG filter types is added.
+*) 17 aug 2011 (!): changed some C zlib related function names.
+*) 16 aug 2011: made the code less wide (max 120 characters per line).
+*) 17 apr 2011: code cleanup. Bugfixes. Convert low to 16-bit per sample colors.
+*) 21 feb 2011: fixed compiling for C90. Fixed compiling with sections disabled.
+*) 11 dec 2010: encoding is made faster, based on suggestion by Peter Eastman
+    to optimize long sequences of zeros.
+*) 13 nov 2010: added LodePNG_InfoColor_hasPaletteAlpha and
+    LodePNG_InfoColor_canHaveAlpha functions for convenience.
+*) 7 nov 2010: added LodePNG_error_text function to get error code description.
+*) 30 okt 2010: made decoding slightly faster
+*) 26 okt 2010: (!) changed some C function and struct names (more consistent).
+     Reorganized the documentation and the declaration order in the header.
+*) 08 aug 2010: only changed some comments and external samples.
+*) 05 jul 2010: fixed bug thanks to warnings in the new gcc version.
+*) 14 mar 2010: fixed bug where too much memory was allocated for char buffers.
+*) 02 sep 2008: fixed bug where it could create empty tree that linux apps could
+    read by ignoring the problem but windows apps couldn't.
+*) 06 jun 2008: added more error checks for out of memory cases.
+*) 26 apr 2008: added a few more checks here and there to ensure more safety.
+*) 06 mar 2008: crash with encoding of strings fixed
+*) 02 feb 2008: support for international text chunks added (iTXt)
+*) 23 jan 2008: small cleanups, and #defines to divide code in sections
+*) 20 jan 2008: support for unknown chunks allowing using LodePNG for an editor.
+*) 18 jan 2008: support for tIME and pHYs chunks added to encoder and decoder.
+*) 17 jan 2008: ability to encode and decode compressed zTXt chunks added
+    Also various fixes, such as in the deflate and the padding bits code.
+*) 13 jan 2008: Added ability to encode Adam7-interlaced images. Improved
+    filtering code of encoder.
+*) 07 jan 2008: (!) changed LodePNG to use ISO C90 instead of C++. A
+    C++ wrapper around this provides an interface almost identical to before.
+    Having LodePNG be pure ISO C90 makes it more portable. The C and C++ code
+    are together in these files but it works both for C and C++ compilers.
+*) 29 dec 2007: (!) changed most integer types to unsigned int + other tweaks
+*) 30 aug 2007: bug fixed which makes this Borland C++ compatible
+*) 09 aug 2007: some VS2005 warnings removed again
+*) 21 jul 2007: deflate code placed in new namespace separate from zlib code
+*) 08 jun 2007: fixed bug with 2- and 4-bit color, and small interlaced images
+*) 04 jun 2007: improved support for Visual Studio 2005: crash with accessing
+    invalid std::vector element [0] fixed, and level 3 and 4 warnings removed
+*) 02 jun 2007: made the encoder add a tag with version by default
+*) 27 may 2007: zlib and png code separated (but still in the same file),
+    simple encoder/decoder functions added for more simple usage cases
+*) 19 may 2007: minor fixes, some code cleaning, new error added (error 69),
+    moved some examples from here to lodepng_examples.cpp
+*) 12 may 2007: palette decoding bug fixed
+*) 24 apr 2007: changed the license from BSD to the zlib license
+*) 11 mar 2007: very simple addition: ability to encode bKGD chunks.
+*) 04 mar 2007: (!) tEXt chunk related fixes, and support for encoding
+    palettized PNG images. Plus little interface change with palette and texts.
+*) 03 mar 2007: Made it encode dynamic Huffman shorter with repeat codes.
+    Fixed a bug where the end code of a block had length 0 in the Huffman tree.
+*) 26 feb 2007: Huffman compression with dynamic trees (BTYPE 2) now implemented
+    and supported by the encoder, resulting in smaller PNGs at the output.
+*) 27 jan 2007: Made the Adler-32 test faster so that a timewaste is gone.
+*) 24 jan 2007: gave encoder an error interface. Added color conversion from any
+    greyscale type to 8-bit greyscale with or without alpha.
+*) 21 jan 2007: (!) Totally changed the interface. It allows more color types
+    to convert to and is more uniform. See the manual for how it works now.
+*) 07 jan 2007: Some cleanup & fixes, and a few changes over the last days:
+    encode/decode custom tEXt chunks, separate classes for zlib & deflate, and
+    at last made the decoder give errors for incorrect Adler32 or Crc.
+*) 01 jan 2007: Fixed bug with encoding PNGs with less than 8 bits per channel.
+*) 29 dec 2006: Added support for encoding images without alpha channel, and
+    cleaned out code as well as making certain parts faster.
+*) 28 dec 2006: Added "Settings" to the encoder.
+*) 26 dec 2006: The encoder now does LZ77 encoding and produces much smaller files now.
+    Removed some code duplication in the decoder. Fixed little bug in an example.
+*) 09 dec 2006: (!) Placed output parameters of public functions as first parameter.
+    Fixed a bug of the decoder with 16-bit per color.
+*) 15 okt 2006: Changed documentation structure
+*) 09 okt 2006: Encoder class added. It encodes a valid PNG image from the
+    given image buffer, however for now it's not compressed.
+*) 08 sep 2006: (!) Changed to interface with a Decoder class
+*) 30 jul 2006: (!) LodePNG_InfoPng , width and height are now retrieved in different
+    way. Renamed decodePNG to decodePNGGeneric.
+*) 29 jul 2006: (!) Changed the interface: image info is now returned as a
+    struct of type LodePNG::LodePNG_Info, instead of a vector, which was a bit clumsy.
+*) 28 jul 2006: Cleaned the code and added new error checks.
+    Corrected terminology "deflate" into "inflate".
+*) 23 jun 2006: Added SDL example in the documentation in the header, this
+    example allows easy debugging by displaying the PNG and its transparency.
+*) 22 jun 2006: (!) Changed way to obtain error value. Added
+    loadFile function for convenience. Made decodePNG32 faster.
+*) 21 jun 2006: (!) Changed type of info vector to unsigned.
+    Changed position of palette in info vector. Fixed an important bug that
+    happened on PNGs with an uncompressed block.
+*) 16 jun 2006: Internally changed unsigned into unsigned where
+    needed, and performed some optimizations.
+*) 07 jun 2006: (!) Renamed functions to decodePNG and placed them
+    in LodePNG namespace. Changed the order of the parameters. Rewrote the
+    documentation in the header. Renamed files to lodepng.cpp and lodepng.h
+*) 22 apr 2006: Optimized and improved some code
+*) 07 sep 2005: (!) Changed to std::vector interface
+*) 12 aug 2005: Initial release (C++, decoder only)
+
+
+13. contact information
+-----------------------
+
+Feel free to contact me with suggestions, problems, comments, ... concerning
+LodePNG. If you encounter a PNG image that doesn't work properly with this
+decoder, feel free to send it and I'll use it to find and fix the problem.
+
+My email address is (puzzle the account and domain together with an @ symbol):
+Domain: gmail dot com.
+Account: lode dot vandevenne.
+
+
+Copyright (c) 2005-2019 Lode Vandevenne
+*/