Merge try 2
This commit is contained in:
parent
ef72f937b4
commit
3ed20d3937
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@ -7,6 +7,10 @@
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#include <turbojpeg.h>
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#include <ctype.h>
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#include <getopt.h>
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#include <dirent.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <libgen.h>
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#include "utils.h"
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#include "jpeg.h"
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@ -47,14 +51,14 @@ cclt_parameters initialize_compression_parameters() {
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return par;
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}
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void validate_parameters(cclt_compress_parameters* pars) {
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void validate_parameters(cclt_parameters* pars) {
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//Either -l or -q must be set but not together
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if (!((pars->lossless == 1) ^ (pars->quality > 0))) {
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if (!((pars->jpeg.lossless == 1) ^ (pars->jpeg.quality > 0))) {
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//Both or none are set
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if (pars->lossless == 1 && pars->quality > 0) {
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if (pars->jpeg.lossless == 1 && pars->jpeg.quality > 0) {
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fprintf(stderr, "-l option can't be used with -q. Either use one or the other. Aborting.\n");
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exit(-1);
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} else if (pars->lossless == 0 && pars->quality <= 0) {
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} else if (pars->jpeg.lossless == 0 && pars->jpeg.quality <= 0) {
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fprintf(stderr, "Either -l or -q must be set. Aborting.\n");
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print_help();
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exit(-2);
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@ -62,7 +66,7 @@ void validate_parameters(cclt_compress_parameters* pars) {
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} else {
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//One of them is set
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//If -q is set check it is within the 1-100 range
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if (!(pars->quality >= 1 && pars->quality <= 100) && pars->lossless == 0) {
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if (!(pars->jpeg.quality >= 1 && pars->jpeg.quality <= 100) && pars->jpeg.lossless == 0) {
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fprintf(stderr, "Quality must be within a [1-100] range. Aborting.\n");
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exit(-3);
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}
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@ -81,10 +85,10 @@ void validate_parameters(cclt_compress_parameters* pars) {
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}
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}
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cclt_compress_parameters parse_arguments(int argc, char* argv[]) {
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cclt_parameters parse_arguments(int argc, char* argv[]) {
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//Initialize default params
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cclt_compress_parameters parameters = initialize_compression_parameters();
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cclt_parameters parameters = initialize_compression_parameters();
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int c;
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while (optind < argc) {
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@ -111,13 +115,13 @@ cclt_compress_parameters parse_arguments(int argc, char* argv[]) {
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fprintf(stderr, "Parameter expected.\n");
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break;
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case 'q':
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parameters.quality = string_to_int(optarg);
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parameters.jpeg.quality = string_to_int(optarg);
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break;
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case 'e':
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parameters.exif_copy = 1;
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parameters.jpeg.exif_copy = 1;
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break;
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case 'l':
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parameters.lossless = 1;
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parameters.jpeg.lossless = 1;
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break;
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case 'o':
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parameters.output_folder = optarg;
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@ -164,19 +168,19 @@ cclt_compress_parameters parse_arguments(int argc, char* argv[]) {
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return parameters;
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}
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int cclt_compress_routine(char* input, char* output, cclt_compress_parameters* pars) {
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int cclt_compress_routine(char* input, char* output, cclt_parameters* pars) {
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//Detect which image type are we compressing
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enum image_type type = detect_image_type(input);
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if (type == JPEG) {
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//Lossy processing just uses the compression method before optimizing
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if (!pars->lossless) {
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cclt_jpeg_compress(output, cclt_jpeg_decompress(input, pars), pars);
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if (!pars->jpeg.lossless) {
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cclt_jpeg_compress(output, cclt_jpeg_decompress(input, &pars->jpeg), &pars->jpeg);
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}
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//Optimize
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cclt_jpeg_optimize(output, output, pars->exif_copy, input);
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cclt_jpeg_optimize(output, output, pars->jpeg.exif_copy, input);
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} else if (type == PNG) {
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cclt_png_optimize(input, output);
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cclt_png_optimize(input, output, &pars->png);
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} else {
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printf("Unknown file type.\n");
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return -1;
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@ -184,7 +188,7 @@ int cclt_compress_routine(char* input, char* output, cclt_compress_parameters* p
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return 0;
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}
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void cclt_start(cclt_compress_parameters* pars, off_t* i_t_size, off_t* o_t_size) {
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void cclt_start(cclt_parameters* pars, off_t* i_t_size, off_t* o_t_size) {
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struct stat st_buf;
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int i = 0;
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@ -6,5 +6,8 @@
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cclt_parameters initialize_compression_parameters();
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cclt_parameters parse_arguments(int argc, char* argv[]);
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int cclt_compress_routine(char* input, char* output, cclt_parameters* pars); //Returns -1 if the file type is unknown
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void cclt_start(cclt_parameters* pars, off_t* i_t_size, off_t* o_t_size);
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//TODO Maybe it's better to return a int
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void validate_parameters(cclt_parameters* pars);
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#endif
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@ -24,8 +24,7 @@ freely, subject to the following restrictions:
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*/
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/*
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The manual and changelog are in the header file "lodepng.h"
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Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C.
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Changelog and manual removed from header
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*/
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#include "lodepng.h"
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823
src/lodepng.h
823
src/lodepng.h
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@ -890,827 +890,4 @@ unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned ch
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} //namespace lodepng
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#endif /*LODEPNG_COMPILE_CPP*/
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/*
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TODO:
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[.] test if there are no memory leaks or security exploits - done a lot but needs to be checked often
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[.] check compatibility with vareous compilers - done but needs to be redone for every newer version
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[X] converting color to 16-bit per channel types
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[ ] read all public PNG chunk types (but never let the color profile and gamma ones touch RGB values)
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[ ] make sure encoder generates no chunks with size > (2^31)-1
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[ ] partial decoding (stream processing)
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[X] let the "isFullyOpaque" function check color keys and transparent palettes too
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[X] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl"
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[ ] don't stop decoding on errors like 69, 57, 58 (make warnings)
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[ ] make option to choose if the raw image with non multiple of 8 bits per scanline should have padding bits or not
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[ ] let the C++ wrapper catch exceptions coming from the standard library and return LodePNG error codes
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*/
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#endif /*LODEPNG_H inclusion guard*/
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/*
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LodePNG Documentation
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---------------------
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0. table of contents
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--------------------
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1. about
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1.1. supported features
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1.2. features not supported
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2. C and C++ version
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3. security
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4. decoding
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5. encoding
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6. color conversions
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6.1. PNG color types
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6.2. color conversions
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6.3. padding bits
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6.4. A note about 16-bits per channel and endianness
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7. error values
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8. chunks and PNG editing
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9. compiler support
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10. examples
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10.1. decoder C++ example
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10.2. decoder C example
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11. changes
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12. contact information
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1. about
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--------
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PNG is a file format to store raster images losslessly with good compression,
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supporting different color types and alpha channel.
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LodePNG is a PNG codec according to the Portable Network Graphics (PNG)
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Specification (Second Edition) - W3C Recommendation 10 November 2003.
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The specifications used are:
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*) Portable Network Graphics (PNG) Specification (Second Edition):
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http://www.w3.org/TR/2003/REC-PNG-20031110
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*) RFC 1950 ZLIB Compressed Data Format version 3.3:
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http://www.gzip.org/zlib/rfc-zlib.html
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*) RFC 1951 DEFLATE Compressed Data Format Specification ver 1.3:
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http://www.gzip.org/zlib/rfc-deflate.html
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The most recent version of LodePNG can currently be found at
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http://lodev.org/lodepng/
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LodePNG works both in C (ISO C90) and C++, with a C++ wrapper that adds
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extra functionality.
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LodePNG exists out of two files:
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-lodepng.h: the header file for both C and C++
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-lodepng.c(pp): give it the name lodepng.c or lodepng.cpp (or .cc) depending on your usage
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If you want to start using LodePNG right away without reading this doc, get the
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examples from the LodePNG website to see how to use it in code, or check the
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smaller examples in chapter 13 here.
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LodePNG is simple but only supports the basic requirements. To achieve
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simplicity, the following design choices were made: There are no dependencies
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on any external library. There are functions to decode and encode a PNG with
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a single function call, and extended versions of these functions taking a
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LodePNGState struct allowing to specify or get more information. By default
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the colors of the raw image are always RGB or RGBA, no matter what color type
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the PNG file uses. To read and write files, there are simple functions to
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convert the files to/from buffers in memory.
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This all makes LodePNG suitable for loading textures in games, demos and small
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programs, ... It's less suitable for full fledged image editors, loading PNGs
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over network (it requires all the image data to be available before decoding can
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begin), life-critical systems, ...
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1.1. supported features
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-----------------------
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The following features are supported by the decoder:
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*) decoding of PNGs with any color type, bit depth and interlace mode, to a 24- or 32-bit color raw image,
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or the same color type as the PNG
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*) encoding of PNGs, from any raw image to 24- or 32-bit color, or the same color type as the raw image
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*) Adam7 interlace and deinterlace for any color type
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*) loading the image from harddisk or decoding it from a buffer from other sources than harddisk
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*) support for alpha channels, including RGBA color model, translucent palettes and color keying
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*) zlib decompression (inflate)
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*) zlib compression (deflate)
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*) CRC32 and ADLER32 checksums
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*) handling of unknown chunks, allowing making a PNG editor that stores custom and unknown chunks.
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*) the following chunks are supported (generated/interpreted) by both encoder and decoder:
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IHDR: header information
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PLTE: color palette
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IDAT: pixel data
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IEND: the final chunk
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tRNS: transparency for palettized images
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tEXt: textual information
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zTXt: compressed textual information
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iTXt: international textual information
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bKGD: suggested background color
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pHYs: physical dimensions
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tIME: modification time
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1.2. features not supported
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---------------------------
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The following features are _not_ supported:
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*) some features needed to make a conformant PNG-Editor might be still missing.
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*) partial loading/stream processing. All data must be available and is processed in one call.
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*) The following public chunks are not supported but treated as unknown chunks by LodePNG
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cHRM, gAMA, iCCP, sRGB, sBIT, hIST, sPLT
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Some of these are not supported on purpose: LodePNG wants to provide the RGB values
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stored in the pixels, not values modified by system dependent gamma or color models.
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2. C and C++ version
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--------------------
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The C version uses buffers allocated with alloc that you need to free()
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yourself. You need to use init and cleanup functions for each struct whenever
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using a struct from the C version to avoid exploits and memory leaks.
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The C++ version has extra functions with std::vectors in the interface and the
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lodepng::State class which is a LodePNGState with constructor and destructor.
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These files work without modification for both C and C++ compilers because all
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the additional C++ code is in "#ifdef __cplusplus" blocks that make C-compilers
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ignore it, and the C code is made to compile both with strict ISO C90 and C++.
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To use the C++ version, you need to rename the source file to lodepng.cpp
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(instead of lodepng.c), and compile it with a C++ compiler.
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To use the C version, you need to rename the source file to lodepng.c (instead
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of lodepng.cpp), and compile it with a C compiler.
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3. Security
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-----------
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Even if carefully designed, it's always possible that LodePNG contains possible
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exploits. If you discover one, please let me know, and it will be fixed.
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When using LodePNG, care has to be taken with the C version of LodePNG, as well
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as the C-style structs when working with C++. The following conventions are used
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for all C-style structs:
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-if a struct has a corresponding init function, always call the init function when making a new one
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-if a struct has a corresponding cleanup function, call it before the struct disappears to avoid memory leaks
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-if a struct has a corresponding copy function, use the copy function instead of "=".
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The destination must also be inited already.
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4. Decoding
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-----------
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Decoding converts a PNG compressed image to a raw pixel buffer.
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Most documentation on using the decoder is at its declarations in the header
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above. For C, simple decoding can be done with functions such as
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lodepng_decode32, and more advanced decoding can be done with the struct
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LodePNGState and lodepng_decode. For C++, all decoding can be done with the
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various lodepng::decode functions, and lodepng::State can be used for advanced
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features.
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When using the LodePNGState, it uses the following fields for decoding:
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*) LodePNGInfo info_png: it stores extra information about the PNG (the input) in here
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*) LodePNGColorMode info_raw: here you can say what color mode of the raw image (the output) you want to get
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*) LodePNGDecoderSettings decoder: you can specify a few extra settings for the decoder to use
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LodePNGInfo info_png
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--------------------
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After decoding, this contains extra information of the PNG image, except the actual
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pixels, width and height because these are already gotten directly from the decoder
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functions.
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It contains for example the original color type of the PNG image, text comments,
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suggested background color, etc... More details about the LodePNGInfo struct are
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at its declaration documentation.
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LodePNGColorMode info_raw
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-------------------------
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When decoding, here you can specify which color type you want
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the resulting raw image to be. If this is different from the colortype of the
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PNG, then the decoder will automatically convert the result. This conversion
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always works, except if you want it to convert a color PNG to greyscale or to
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a palette with missing colors.
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By default, 32-bit color is used for the result.
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LodePNGDecoderSettings decoder
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------------------------------
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The settings can be used to ignore the errors created by invalid CRC and Adler32
|
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chunks, and to disable the decoding of tEXt chunks.
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There's also a setting color_convert, true by default. If false, no conversion
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is done, the resulting data will be as it was in the PNG (after decompression)
|
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and you'll have to puzzle the colors of the pixels together yourself using the
|
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color type information in the LodePNGInfo.
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5. Encoding
|
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-----------
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Encoding converts a raw pixel buffer to a PNG compressed image.
|
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|
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Most documentation on using the encoder is at its declarations in the header
|
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above. For C, simple encoding can be done with functions such as
|
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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
|
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various lodepng::encode functions, and lodepng::State can be used for advanced
|
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features.
|
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Like the decoder, the encoder can also give errors. However it gives less errors
|
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since the encoder input is trusted, the decoder input (a PNG image that could
|
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be forged by anyone) is not trusted.
|
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|
||||
When using the LodePNGState, it uses the following fields for encoding:
|
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*) LodePNGInfo info_png: here you specify how you want the PNG (the output) to be.
|
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*) LodePNGColorMode info_raw: here you say what color type of the raw image (the input) has
|
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*) LodePNGEncoderSettings encoder: you can specify a few settings for the encoder to use
|
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LodePNGInfo info_png
|
||||
--------------------
|
||||
|
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When encoding, you use this the opposite way as when decoding: for encoding,
|
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you fill in the values you want the PNG to have before encoding. By default it's
|
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not needed to specify a color type for the PNG since it's automatically chosen,
|
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but it's possible to choose it yourself given the right settings.
|
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|
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The encoder will not always exactly match the LodePNGInfo struct you give,
|
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it tries as close as possible. Some things are ignored by the encoder. The
|
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encoder uses, for example, the following settings from it when applicable:
|
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colortype and bitdepth, text chunks, time chunk, the color key, the palette, the
|
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background color, the interlace method, unknown chunks, ...
|
||||
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When encoding to a PNG with colortype 3, the encoder will generate a PLTE chunk.
|
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If the palette contains any colors for which the alpha channel is not 255 (so
|
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there are translucent colors in the palette), it'll add a tRNS chunk.
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LodePNGColorMode info_raw
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-------------------------
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You specify the color type of the raw image that you give to the input here,
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including a possible transparent color key and palette you happen to be using in
|
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your raw image data.
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By default, 32-bit color is assumed, meaning your input has to be in RGBA
|
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format with 4 bytes (unsigned chars) per pixel.
|
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LodePNGEncoderSettings encoder
|
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------------------------------
|
||||
|
||||
The following settings are supported (some are in sub-structs):
|
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*) auto_convert: when this option is enabled, the encoder will
|
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automatically choose the smallest possible color mode (including color key) that
|
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can encode the colors of all pixels without information loss.
|
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*) btype: the block type for LZ77. 0 = uncompressed, 1 = fixed huffman tree,
|
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2 = dynamic huffman tree (best compression). Should be 2 for proper
|
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compression.
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*) use_lz77: whether or not to use LZ77 for compressed block types. Should be
|
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true for proper compression.
|
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*) windowsize: the window size used by the LZ77 encoder (1 - 32768). Has value
|
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2048 by default, but can be set to 32768 for better, but slow, compression.
|
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*) force_palette: if colortype is 2 or 6, you can make the encoder write a PLTE
|
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chunk if force_palette is true. This can used as suggested palette to convert
|
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to by viewers that don't support more than 256 colors (if those still exist)
|
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*) add_id: add text chunk "Encoder: LodePNG <version>" to the image.
|
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*) text_compression: default 1. If 1, it'll store texts as zTXt instead of tEXt chunks.
|
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zTXt chunks use zlib compression on the text. This gives a smaller result on
|
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large texts but a larger result on small texts (such as a single program name).
|
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It's all tEXt or all zTXt though, there's no separate setting per text yet.
|
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|
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|
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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, greyscale 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 greyscale 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 grey
|
||||
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: greyscale, bit depths 1, 2, 4, 8, 16
|
||||
2: RGB, bit depths 8 and 16
|
||||
3: palette, bit depths 1, 2, 4 and 8
|
||||
4: greyscale 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 of the simple function of LodePNG you're using.
|
||||
|
||||
If, when encoding, you use another color type than the default in the input
|
||||
image, you need to specify its color type and bit depth in the LodePNGColorMode
|
||||
of the raw image, or use the parameters of the simplefunction of LodePNG you're
|
||||
using.
|
||||
|
||||
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 LAC_NONE, and specify the color type you want in the LodePNGInfo of the
|
||||
encoder.
|
||||
|
||||
If you do any of the above, LodePNG may need to do a color conversion, which
|
||||
follows the rules below, and may sometimes not be allowed.
|
||||
|
||||
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.
|
||||
|
||||
Non supported color conversions:
|
||||
-color to greyscale: no error is thrown, but the result will look ugly because
|
||||
only the red channel is taken
|
||||
-anything, to palette when that palette does not have that 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 grey or grey+alpha, to grey or grey+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:
|
||||
-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
|
||||
LAC_NO.
|
||||
-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.
|
||||
|
||||
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.
|
||||
|
||||
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.
|
||||
|
||||
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.
|
||||
|
||||
*) Mingw
|
||||
|
||||
The Mingw compiler (a port of gcc) for Windows is fully supported by LodePNG.
|
||||
|
||||
*) Visual Studio 2005 and up, Visual C++ Express Edition 2005 and up
|
||||
|
||||
Visual Studio may give warnings about 'fopen' being deprecated. A multiplatform library
|
||||
can't support the proposed Visual Studio alternative however, so LodePNG keeps using
|
||||
fopen. If you don't want to see the deprecated warnings, put this on top of lodepng.h
|
||||
before the inclusions:
|
||||
#define _CRT_SECURE_NO_DEPRECATE
|
||||
|
||||
Other than the above warnings, LodePNG should be warning-free with warning
|
||||
level 3 (W3). Warning level 4 (W4) will give warnings about integer conversions.
|
||||
I'm not planning to resolve these warnings. To get rid of them, let Visual
|
||||
Studio use warning level W3 for lodepng.cpp only: right click lodepng.cpp,
|
||||
Properties, C/C++, General, Warning Level: Level 3 (/W3).
|
||||
|
||||
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".
|
||||
That 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.
|
||||
|
||||
*) Visual Studio 6.0
|
||||
|
||||
LodePNG support for Visual Studio 6.0 is not guaranteed because VS6 doesn't
|
||||
follow the C++ standard correctly.
|
||||
|
||||
*) Comeau C/C++
|
||||
|
||||
Vesion 20070107 compiles without problems on the Comeau C/C++ Online Test Drive
|
||||
at http://www.comeaucomputing.com/tryitout in both C90 and C++ mode.
|
||||
|
||||
*) Compilers on Macintosh
|
||||
|
||||
LodePNG has been reported to work both with the gcc and LLVM for Macintosh, both
|
||||
for C and C++.
|
||||
|
||||
*) Other Compilers
|
||||
|
||||
If you encounter problems on other compilers, feel free to let me know and I may
|
||||
try to fix it if the compiler is modern 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. 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.
|
||||
|
||||
*) 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 shrinked 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 vareous 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)
|
||||
|
||||
|
||||
12. 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) 2005-2013 Lode Vandevenne
|
||||
*/
|
||||
|
|
21
src/utils.c
21
src/utils.c
|
@ -30,28 +30,28 @@ int string_to_int(char* in_string) {
|
|||
|
||||
//Check errors
|
||||
if ((errno == ERANGE) || (errno != 0 && value == 0)) {
|
||||
perror("strtol");
|
||||
exit(-8);
|
||||
}
|
||||
perror("strtol");
|
||||
exit(-8);
|
||||
}
|
||||
|
||||
if (endptr == in_string) {
|
||||
fprintf(stderr, "Parse error: No digits were found for -q option. Aborting.\n");
|
||||
exit(-7);
|
||||
}
|
||||
fprintf(stderr, "Parse error: No digits were found for -q option. Aborting.\n");
|
||||
exit(-7);
|
||||
}
|
||||
|
||||
return value;
|
||||
}
|
||||
|
||||
void print_help() {
|
||||
fprintf(stdout,
|
||||
"CCLT - Caesium Command Line Tools\n\n"
|
||||
"Usage: caesiumclt [OPTIONs] INPUT...\n"
|
||||
"CaesiumCLT - Caesium Command Line Tools\n\n"
|
||||
"Usage: caesiumclt [OPTIONS] INPUT...\n"
|
||||
"Compress your pictures up to 90%% without visible quality loss.\n\n"
|
||||
|
||||
"Options:\n"
|
||||
"\t-q\tset output file quality between [1-100], ignored for non-JPEGs\n"
|
||||
"\t-q\tset output file quality between [1-100], JPEG only\n"
|
||||
"\t-e\tkeeps EXIF info during compression\n"
|
||||
"\t-o\tcompress to custom folder\n"
|
||||
"\t-o\toutput folder\n"
|
||||
"\t-l\tuse lossless optimization\n"
|
||||
"\t-R\tif input is a folder, scan subfolders too\n"
|
||||
//TODO Remove this warning
|
||||
|
@ -64,7 +64,6 @@ void print_help() {
|
|||
//TODO Recheck
|
||||
int mkpath(const char *pathname, mode_t mode) {
|
||||
|
||||
//Need include in Linux, not on OSX
|
||||
char parent[PATH_MAX], *p;
|
||||
/* make a parent directory path */
|
||||
strncpy(parent, pathname, sizeof(parent));
|
||||
|
|
Loading…
Reference in New Issue