OcPngLib: Merge functional lodepng changes from upstream

Library/OcPngLib/lodepng.c

@@ -1,5 +1,5 @@
 /*
-LodePNG version 20181230
+LodePNG version 20190210
 
 Copyright (c) 2018 savvas
 Copyright (c) 2018 vit9696
@@ -122,7 +122,7 @@ void* lodepng_realloc(void* ptr, size_t new_size) {
 #pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/
 #endif /*_MSC_VER */
 
-const char* LODEPNG_VERSION_STRING = "20181230";
+const char* LODEPNG_VERSION_STRING = "20190210";
 
 /*
 This source file is built up in the following large parts. The code sections
@@ -2772,6 +2772,7 @@ static unsigned lodepng_assign_icc(LodePNGInfo* info, const char* name, const un
 
 unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) {
   if(info->iccp_name) lodepng_clear_icc(info);
+  info->iccp_defined = 1;
 
   return lodepng_assign_icc(info, name, profile, profile_size);
 }
@@ -2781,6 +2782,7 @@ void lodepng_clear_icc(LodePNGInfo* info) {
   lodepng_free(info->iccp_profile);
   info->iccp_profile = NULL;
   info->iccp_profile_size = 0;
+  info->iccp_defined = 0;
 }
 #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
 
@@ -4415,8 +4417,10 @@ static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h,
   unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/
 #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
 
-  /*provide some proper output values if error will happen*/
+
+  /* safe output values in case error happens */
   *out = 0;
+  *w = *h = 0;
 
   state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/
   if(state->error) return;
@@ -4648,6 +4652,9 @@ unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, cons
   unsigned char* buffer = 0;
   size_t buffersize;
   unsigned error;
+  /* safe output values in case error happens */
+  *out = 0;
+  *w = *h = 0;
   error = lodepng_load_file(&buffer, &buffersize, filename);
   if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth);
   lodepng_free(buffer);
@@ -5999,6 +6006,8 @@ unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
 unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::string& filename,
                 LodePNGColorType colortype, unsigned bitdepth) {
   std::vector<unsigned char> buffer;
+  /* safe output values in case error happens */
+  w = h = 0;
   unsigned error = load_file(buffer, filename);
   if(error) return error;
   return decode(out, w, h, buffer, colortype, bitdepth);

Library/OcPngLib/lodepng.h

@@ -1,5 +1,5 @@
 /*
-LodePNG version 20181230
+LodePNG version 20190210
 
 Copyright (c) 2018 savvas
 Copyright (c) 2018 vit9696
@@ -1071,17 +1071,21 @@ TODO:
 [.] 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
+[ ] 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"
-[ ] don't stop decoding on errors like 69, 57, 58 (make warnings)
+[ ] 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, ...
-[ ] errors with line numbers (and version)
+[ ] 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*/
@@ -1176,8 +1180,10 @@ The following features are supported by the decoder:
 *) 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 (generated/interpreted) by both encoder and decoder:
+*) the following chunks are supported by both encoder and decoder:
     IHDR: header information
     PLTE: color palette
     IDAT: pixel data
@@ -1189,6 +1195,10 @@ The following features are supported by the decoder:
     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
 ---------------------------
@@ -1197,10 +1207,10 @@ 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 supported but treated as unknown chunks by LodePNG
-    cHRM, gAMA, iCCP, sRGB, sBIT, hIST, sPLT
-   Some of these are not supported on purpose: LodePNG wants to provide the RGB values
-   stored in the pixels, not values modified by system dependent gamma or color models.
+*) The following public chunks are not (yet) supported but treated as unknown chunks by LodePNG:
+    sBIT
+    hIST
+    sPLT
 
 
 2. C and C++ version
@@ -1454,15 +1464,22 @@ To avoid some confusion:
  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: 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
+-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 grey or grey+alpha, to grey or grey+alpha
+-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
@@ -1475,10 +1492,6 @@ false.
 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
 -----------------
 
@@ -1948,5 +1961,5 @@ Domain: gmail dot com.
 Account: lode dot vandevenne.
 
 
-Copyright (c) 2005-2018 Lode Vandevenne
+Copyright (c) 2005-2019 Lode Vandevenne
 */