libpng: fix APNG patch

1 files changed, 473 insertions, 487 deletions

diff --git a/package/libpng/patches/libpng-1.6.22-apng.patch b/package/libpng/patches/libpng-1.6.22-apng.patch
index 66440b70f..24cc9aa9a 100644
--- a/package/libpng/patches/libpng-1.6.22-apng.patch
+++ b/package/libpng/patches/libpng-1.6.22-apng.patch
@@ -1,7 +1,6 @@
-Index: LICENSE
-===================================================================
---- LICENSE
-+++ LICENSE
+diff -Nur libpng-1.6.22.orig/LICENSE libpng-1.6.22/LICENSE
+--- libpng-1.6.22.orig/LICENSE	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/LICENSE	2016-10-01 00:22:37.029393861 +0200
 @@ -8,6 +8,12 @@
  If you modify libpng you may insert additional notices immediately following
  this sentence.
@@ -15,115 +14,38 @@ Index: LICENSE
  This code is released under the libpng license.
  
  libpng versions 1.0.7, July 1, 2000 through 1.6.22, May 26, 2016 are
-Index: pngread.c
-===================================================================
---- pngread.c
-+++ pngread.c
-@@ -158,6 +158,9 @@
- 
-       else if (chunk_name == png_IDAT)
-       {
-+#ifdef PNG_READ_APNG_SUPPORTED
-+         png_have_info(png_ptr, info_ptr);
-+#endif
-          png_ptr->idat_size = length;
-          break;
-       }
-@@ -247,6 +250,17 @@
-          png_handle_iTXt(png_ptr, info_ptr, length);
+diff -Nur libpng-1.6.22.orig/png.c libpng-1.6.22/png.c
+--- libpng-1.6.22.orig/png.c	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/png.c	2016-10-01 00:22:37.029393861 +0200
+@@ -775,17 +775,21 @@
+ #else
+ #  ifdef __STDC__
+    return PNG_STRING_NEWLINE \
+-      "libpng version 1.6.22 - May 26, 2016" PNG_STRING_NEWLINE \
++      "libpng version 1.6.22+apng - May 26, 2016" PNG_STRING_NEWLINE \
+       "Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson" \
+       PNG_STRING_NEWLINE \
+       "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
+       "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
+-      PNG_STRING_NEWLINE;
++      PNG_STRING_NEWLINE \
++      "Portions Copyright (c) 2006-2007 Andrew Smith" PNG_STRING_NEWLINE \
++      "Portions Copyright (c) 2008-2016 Max Stepin" PNG_STRING_NEWLINE ;
+ #  else
+-   return "libpng version 1.6.22 - May 26, 2016\
++   return "libpng version 1.6.22+apng - May 26, 2016\
+       Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
+       Copyright (c) 1996-1997 Andreas Dilger\
+-      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
++      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\
++      Portions Copyright (c) 2006-2007 Andrew Smith\
++      Portions Copyright (c) 2008-2016 Max Stepin";
+ #  endif
  #endif
- 
-+#ifdef PNG_READ_APNG_SUPPORTED
-+      else if (chunk_name == png_acTL)
-+         png_handle_acTL(png_ptr, info_ptr, length);
-+
-+      else if (chunk_name == png_fcTL)
-+         png_handle_fcTL(png_ptr, info_ptr, length);
-+
-+      else if (chunk_name == png_fdAT)
-+         png_handle_fdAT(png_ptr, info_ptr, length);
-+#endif
-+
-       else
-          png_handle_unknown(png_ptr, info_ptr, length,
-             PNG_HANDLE_CHUNK_AS_DEFAULT);
-@@ -254,6 +268,72 @@
  }
- #endif /* SEQUENTIAL_READ */
- 
-+#ifdef PNG_READ_APNG_SUPPORTED
-+void PNGAPI
-+png_read_frame_head(png_structp png_ptr, png_infop info_ptr)
-+{
-+    png_byte have_chunk_after_DAT; /* after IDAT or after fdAT */
-+
-+    png_debug(0, "Reading frame head");
-+
-+    if ((png_ptr->mode & PNG_HAVE_acTL) == 0)
-+        png_error(png_ptr, "attempt to png_read_frame_head() but "
-+                           "no acTL present");
-+
-+    /* do nothing for the main IDAT */
-+    if (png_ptr->num_frames_read == 0)
-+        return;
-+
-+    png_read_reset(png_ptr);
-+    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
-+    png_ptr->mode &= ~PNG_HAVE_fcTL;
-+
-+    have_chunk_after_DAT = 0;
-+    for (;;)
-+    {
-+        png_uint_32 length = png_read_chunk_header(png_ptr);
-+
-+        if (png_ptr->chunk_name == png_IDAT)
-+        {
-+            /* discard trailing IDATs for the first frame */
-+            if (have_chunk_after_DAT != 0 || png_ptr->num_frames_read > 1)
-+                png_error(png_ptr, "png_read_frame_head(): out of place IDAT");
-+            png_crc_finish(png_ptr, length);
-+        }
-+
-+        else if (png_ptr->chunk_name == png_fcTL)
-+        {
-+            png_handle_fcTL(png_ptr, info_ptr, length);
-+            have_chunk_after_DAT = 1;
-+        }
-+
-+        else if (png_ptr->chunk_name == png_fdAT)
-+        {
-+            png_ensure_sequence_number(png_ptr, length);
-+
-+            /* discard trailing fdATs for frames other than the first */
-+            if (have_chunk_after_DAT == 0 && png_ptr->num_frames_read > 1)
-+                png_crc_finish(png_ptr, length - 4);
-+            else if(png_ptr->mode & PNG_HAVE_fcTL)
-+            {
-+                png_ptr->idat_size = length - 4;
-+                png_ptr->mode |= PNG_HAVE_IDAT;
-+
-+                break;
-+            }
-+            else
-+                png_error(png_ptr, "png_read_frame_head(): out of place fdAT");
-+        }
-+        else
-+        {
-+            png_warning(png_ptr, "Skipped (ignored) a chunk "
-+                                 "between APNG chunks");
-+            png_crc_finish(png_ptr, length);
-+        }
-+    }
-+}
-+#endif /* READ_APNG */
-+
- /* Optional call to update the users info_ptr structure */
- void PNGAPI
- png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
-Index: pngget.c
-===================================================================
---- pngget.c
-+++ pngget.c
+diff -Nur libpng-1.6.22.orig/pngget.c libpng-1.6.22/pngget.c
+--- libpng-1.6.22.orig/pngget.c	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/pngget.c	2016-10-01 00:22:37.029393861 +0200
 @@ -1216,4 +1216,166 @@
  #  endif
  #endif
@@ -291,40 +213,9 @@ Index: pngget.c
 +}
 +#endif /* APNG */
  #endif /* READ || WRITE */
-Index: png.c
-===================================================================
---- png.c
-+++ png.c
-@@ -775,17 +775,21 @@
- #else
- #  ifdef __STDC__
-    return PNG_STRING_NEWLINE \
--      "libpng version 1.6.22 - May 26, 2016" PNG_STRING_NEWLINE \
-+      "libpng version 1.6.22+apng - May 26, 2016" PNG_STRING_NEWLINE \
-       "Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson" \
-       PNG_STRING_NEWLINE \
-       "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
-       "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
--      PNG_STRING_NEWLINE;
-+      PNG_STRING_NEWLINE \
-+      "Portions Copyright (c) 2006-2007 Andrew Smith" PNG_STRING_NEWLINE \
-+      "Portions Copyright (c) 2008-2016 Max Stepin" PNG_STRING_NEWLINE ;
- #  else
--   return "libpng version 1.6.22 - May 26, 2016\
-+   return "libpng version 1.6.22+apng - May 26, 2016\
-       Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
-       Copyright (c) 1996-1997 Andreas Dilger\
--      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
-+      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\
-+      Portions Copyright (c) 2006-2007 Andrew Smith\
-+      Portions Copyright (c) 2008-2016 Max Stepin";
- #  endif
- #endif
- }
-Index: png.h
-===================================================================
---- png.h
-+++ png.h
+diff -Nur libpng-1.6.22.orig/png.h libpng-1.6.22/png.h
+--- libpng-1.6.22.orig/png.h	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/png.h	2016-10-01 00:22:37.029393861 +0200
 @@ -23,6 +23,12 @@
   * If you modify libpng you may insert additional notices immediately following
   * this sentence.
@@ -489,92 +380,9 @@ Index: png.h
  #endif
  
  #ifdef __cplusplus
-Index: pngpriv.h
-===================================================================
---- pngpriv.h
-+++ pngpriv.h
-@@ -537,6 +537,10 @@
- #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
-                    /*             0x4000 (unused) */
- #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
-+#ifdef PNG_APNG_SUPPORTED
-+#define PNG_HAVE_acTL            0x10000
-+#define PNG_HAVE_fcTL            0x20000
-+#endif
- 
- /* Flags for the transformations the PNG library does on the image data */
- #define PNG_BGR                 0x0001
-@@ -754,6 +758,16 @@
- #define png_tRNS PNG_U32(116,  82,  78,  83)
- #define png_zTXt PNG_U32(122,  84,  88, 116)
- 
-+#ifdef PNG_APNG_SUPPORTED
-+#define png_acTL PNG_U32( 97,  99,  84,  76)
-+#define png_fcTL PNG_U32(102,  99,  84,  76)
-+#define png_fdAT PNG_U32(102, 100,  65,  84)
-+
-+/* For png_struct.apng_flags: */
-+#define PNG_FIRST_FRAME_HIDDEN       0x0001
-+#define PNG_APNG_APP                 0x0002
-+#endif
-+
- /* The following will work on (signed char*) strings, whereas the get_uint_32
-  * macro will fail on top-bit-set values because of the sign extension.
-  */
-@@ -1441,6 +1455,49 @@
- 
- #endif /* PROGRESSIVE_READ */
- 
-+#ifdef PNG_APNG_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_ensure_fcTL_is_valid,(png_structp png_ptr,
-+   png_uint_32 width, png_uint_32 height,
-+   png_uint_32 x_offset, png_uint_32 y_offset,
-+   png_uint_16 delay_num, png_uint_16 delay_den,
-+   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
-+
-+#ifdef PNG_READ_APNG_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_handle_acTL,(png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_handle_fcTL,(png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_handle_fdAT,(png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_have_info,(png_structp png_ptr,
-+   png_infop info_ptr),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_ensure_sequence_number,(png_structp png_ptr,
-+   png_uint_32 length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_read_reset,(png_structp png_ptr),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_read_reinit,(png_structp png_ptr,
-+   png_infop info_ptr),PNG_EMPTY);
-+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_progressive_read_reset,(png_structp png_ptr),
-+   PNG_EMPTY);
-+#endif /* PROGRESSIVE_READ */
-+#endif /* READ_APNG */
-+
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+PNG_INTERNAL_FUNCTION(void,png_write_acTL,(png_structp png_ptr,
-+   png_uint_32 num_frames, png_uint_32 num_plays),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_fcTL,(png_structp png_ptr,
-+   png_uint_32 width, png_uint_32 height,
-+   png_uint_32 x_offset, png_uint_32 y_offset,
-+   png_uint_16 delay_num, png_uint_16 delay_den,
-+   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_fdAT,(png_structp png_ptr,
-+   png_const_bytep data, png_size_t length),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_reset,(png_structp png_ptr),PNG_EMPTY);
-+PNG_INTERNAL_FUNCTION(void,png_write_reinit,(png_structp png_ptr,
-+   png_infop info_ptr, png_uint_32 width, png_uint_32 height),PNG_EMPTY);
-+#endif /* WRITE_APNG */
-+#endif /* APNG */
-+
- /* Added at libpng version 1.6.0 */
- #ifdef PNG_GAMMA_SUPPORTED
- PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
-Index: pnginfo.h
-===================================================================
---- pnginfo.h
-+++ pnginfo.h
+diff -Nur libpng-1.6.22.orig/pnginfo.h libpng-1.6.22/pnginfo.h
+--- libpng-1.6.22.orig/pnginfo.h	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/pnginfo.h	2016-10-01 00:22:37.033394016 +0200
 @@ -255,5 +255,18 @@
     png_bytepp row_pointers;        /* the image bits */
  #endif
@@ -594,112 +402,9 @@ Index: pnginfo.h
 +
  };
  #endif /* PNGINFO_H */
-Index: pngstruct.h
-===================================================================
---- pngstruct.h
-+++ pngstruct.h
-@@ -403,6 +403,27 @@
-    png_byte filter_type;
- #endif
- 
-+#ifdef PNG_APNG_SUPPORTED
-+   png_uint_32 apng_flags;
-+   png_uint_32 next_seq_num;         /* next fcTL/fdAT chunk sequence number */
-+   png_uint_32 first_frame_width;
-+   png_uint_32 first_frame_height;
-+
-+#ifdef PNG_READ_APNG_SUPPORTED
-+   png_uint_32 num_frames_read;      /* incremented after all image data of */
-+                                     /* a frame is read */
-+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-+   png_progressive_frame_ptr frame_info_fn; /* frame info read callback */
-+   png_progressive_frame_ptr frame_end_fn;  /* frame data read callback */
-+#endif
-+#endif
-+
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+   png_uint_32 num_frames_to_write;
-+   png_uint_32 num_frames_written;
-+#endif
-+#endif /* APNG */
-+
- /* New members added in libpng-1.2.0 */
- 
- /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
-Index: pngwrite.c
-===================================================================
---- pngwrite.c
-+++ pngwrite.c
-@@ -128,6 +128,10 @@
-        * the application continues writing the PNG.  So check the 'invalid'
-        * flag here too.
-        */
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+   if ((info_ptr->valid & PNG_INFO_acTL) != 0)
-+      png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
-+#endif
- #ifdef PNG_GAMMA_SUPPORTED
- #  ifdef PNG_WRITE_gAMA_SUPPORTED
-       if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-@@ -360,6 +364,11 @@
-    if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
-       png_error(png_ptr, "No IDATs written into file");
- 
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+   if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
-+      png_error(png_ptr, "Not enough frames written");
-+#endif
-+
- #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
-    if (png_ptr->num_palette_max > png_ptr->num_palette)
-       png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
-@@ -2380,4 +2389,42 @@
- }
- #endif /* SIMPLIFIED_WRITE_STDIO */
- #endif /* SIMPLIFIED_WRITE */
-+
-+#ifdef PNG_WRITE_APNG_SUPPORTED
-+void PNGAPI
-+png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
-+    png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
-+    png_uint_32 x_offset, png_uint_32 y_offset,
-+    png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
-+    png_byte blend_op)
-+{
-+    png_debug(1, "in png_write_frame_head");
-+
-+    /* there is a chance this has been set after png_write_info was called,
-+    * so it would be set but not written. is there a way to be sure? */
-+    if ((info_ptr->valid & PNG_INFO_acTL) == 0)
-+        png_error(png_ptr, "png_write_frame_head(): acTL not set");
-+
-+    png_write_reset(png_ptr);
-+
-+    png_write_reinit(png_ptr, info_ptr, width, height);
-+
-+    if ((png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) == 0 ||
-+        png_ptr->num_frames_written != 0)
-+        png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
-+                       delay_num, delay_den, dispose_op, blend_op);
-+
-+    PNG_UNUSED(row_pointers)
-+}
-+
-+void PNGAPI
-+png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
-+{
-+    png_debug(1, "in png_write_frame_tail");
-+
-+    png_ptr->num_frames_written++;
-+
-+    PNG_UNUSED(info_ptr)
-+}
-+#endif /* WRITE_APNG */
- #endif /* WRITE */
-Index: pngpread.c
-===================================================================
---- pngpread.c
-+++ pngpread.c
+diff -Nur libpng-1.6.22.orig/pngpread.c libpng-1.6.22/pngpread.c
+--- libpng-1.6.22.orig/pngpread.c	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/pngpread.c	2016-10-01 00:22:37.033394016 +0200
 @@ -194,6 +194,89 @@
  
     chunk_name = png_ptr->chunk_name;
@@ -930,173 +635,194 @@ Index: pngpread.c
  png_voidp PNGAPI
  png_get_progressive_ptr(png_const_structrp png_ptr)
  {
-Index: pngset.c
-===================================================================
---- pngset.c
-+++ pngset.c
-@@ -241,6 +241,11 @@
-    info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
- 
-    info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
-+
+diff -Nur libpng-1.6.22.orig/pngpriv.h libpng-1.6.22/pngpriv.h
+--- libpng-1.6.22.orig/pngpriv.h	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/pngpriv.h	2016-10-01 00:22:37.033394016 +0200
+@@ -537,6 +537,10 @@
+ #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
+                    /*             0x4000 (unused) */
+ #define PNG_IS_READ_STRUCT        0x8000 /* Else is a write struct */
 +#ifdef PNG_APNG_SUPPORTED
-+   /* for non-animated png. this may be overwritten from an acTL chunk later */
-+   info_ptr->num_frames = 1;
++#define PNG_HAVE_acTL            0x10000
++#define PNG_HAVE_fcTL            0x20000
 +#endif
- }
  
- #ifdef PNG_oFFs_SUPPORTED
-@@ -1094,6 +1099,146 @@
- }
- #endif /* sPLT */
+ /* Flags for the transformations the PNG library does on the image data */
+ #define PNG_BGR                 0x0001
+@@ -754,6 +758,16 @@
+ #define png_tRNS PNG_U32(116,  82,  78,  83)
+ #define png_zTXt PNG_U32(122,  84,  88, 116)
  
 +#ifdef PNG_APNG_SUPPORTED
-+png_uint_32 PNGAPI
-+png_set_acTL(png_structp png_ptr, png_infop info_ptr,
-+    png_uint_32 num_frames, png_uint_32 num_plays)
-+{
-+    png_debug1(1, "in %s storage function", "acTL");
-+
-+    if (png_ptr == NULL || info_ptr == NULL)
-+    {
-+        png_warning(png_ptr,
-+                    "Call to png_set_acTL() with NULL png_ptr "
-+                    "or info_ptr ignored");
-+        return (0);
-+    }
-+    if (num_frames == 0)
-+    {
-+        png_warning(png_ptr,
-+                    "Ignoring attempt to set acTL with num_frames zero");
-+        return (0);
-+    }
-+    if (num_frames > PNG_UINT_31_MAX)
-+    {
-+        png_warning(png_ptr,
-+                    "Ignoring attempt to set acTL with num_frames > 2^31-1");
-+        return (0);
-+    }
-+    if (num_plays > PNG_UINT_31_MAX)
-+    {
-+        png_warning(png_ptr,
-+                    "Ignoring attempt to set acTL with num_plays > 2^31-1");
-+        return (0);
-+    }
-+
-+    info_ptr->num_frames = num_frames;
-+    info_ptr->num_plays = num_plays;
++#define png_acTL PNG_U32( 97,  99,  84,  76)
++#define png_fcTL PNG_U32(102,  99,  84,  76)
++#define png_fdAT PNG_U32(102, 100,  65,  84)
 +
-+    info_ptr->valid |= PNG_INFO_acTL;
++/* For png_struct.apng_flags: */
++#define PNG_FIRST_FRAME_HIDDEN       0x0001
++#define PNG_APNG_APP                 0x0002
++#endif
 +
-+    return (1);
-+}
+ /* The following will work on (signed char*) strings, whereas the get_uint_32
+  * macro will fail on top-bit-set values because of the sign extension.
+  */
+@@ -1441,6 +1455,49 @@
+ 
+ #endif /* PROGRESSIVE_READ */
+ 
++#ifdef PNG_APNG_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_ensure_fcTL_is_valid,(png_structp png_ptr,
++   png_uint_32 width, png_uint_32 height,
++   png_uint_32 x_offset, png_uint_32 y_offset,
++   png_uint_16 delay_num, png_uint_16 delay_den,
++   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
 +
-+/* delay_num and delay_den can hold any 16-bit values including zero */
-+png_uint_32 PNGAPI
-+png_set_next_frame_fcTL(png_structp png_ptr, png_infop info_ptr,
-+    png_uint_32 width, png_uint_32 height,
-+    png_uint_32 x_offset, png_uint_32 y_offset,
-+    png_uint_16 delay_num, png_uint_16 delay_den,
-+    png_byte dispose_op, png_byte blend_op)
-+{
-+    png_debug1(1, "in %s storage function", "fcTL");
++#ifdef PNG_READ_APNG_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_handle_acTL,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_handle_fcTL,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_handle_fdAT,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_have_info,(png_structp png_ptr,
++   png_infop info_ptr),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_ensure_sequence_number,(png_structp png_ptr,
++   png_uint_32 length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_read_reset,(png_structp png_ptr),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_read_reinit,(png_structp png_ptr,
++   png_infop info_ptr),PNG_EMPTY);
++#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_progressive_read_reset,(png_structp png_ptr),
++   PNG_EMPTY);
++#endif /* PROGRESSIVE_READ */
++#endif /* READ_APNG */
 +
-+    if (png_ptr == NULL || info_ptr == NULL)
-+    {
-+        png_warning(png_ptr,
-+                    "Call to png_set_fcTL() with NULL png_ptr or info_ptr "
-+                    "ignored");
-+        return (0);
-+    }
++#ifdef PNG_WRITE_APNG_SUPPORTED
++PNG_INTERNAL_FUNCTION(void,png_write_acTL,(png_structp png_ptr,
++   png_uint_32 num_frames, png_uint_32 num_plays),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_fcTL,(png_structp png_ptr,
++   png_uint_32 width, png_uint_32 height,
++   png_uint_32 x_offset, png_uint_32 y_offset,
++   png_uint_16 delay_num, png_uint_16 delay_den,
++   png_byte dispose_op, png_byte blend_op),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_fdAT,(png_structp png_ptr,
++   png_const_bytep data, png_size_t length),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_reset,(png_structp png_ptr),PNG_EMPTY);
++PNG_INTERNAL_FUNCTION(void,png_write_reinit,(png_structp png_ptr,
++   png_infop info_ptr, png_uint_32 width, png_uint_32 height),PNG_EMPTY);
++#endif /* WRITE_APNG */
++#endif /* APNG */
 +
-+    png_ensure_fcTL_is_valid(png_ptr, width, height, x_offset, y_offset,
-+                             delay_num, delay_den, dispose_op, blend_op);
+ /* Added at libpng version 1.6.0 */
+ #ifdef PNG_GAMMA_SUPPORTED
+ PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
+diff -Nur libpng-1.6.22.orig/pngread.c libpng-1.6.22/pngread.c
+--- libpng-1.6.22.orig/pngread.c	2016-05-26 05:41:46.000000000 +0200
++++ libpng-1.6.22/pngread.c	2016-10-01 00:22:37.029393861 +0200
+@@ -158,6 +158,9 @@
+ 
+       else if (chunk_name == png_IDAT)
+       {
++#ifdef PNG_READ_APNG_SUPPORTED
++         png_have_info(png_ptr, info_ptr);
++#endif
+          png_ptr->idat_size = length;
+          break;
+       }
+@@ -247,6 +250,17 @@
+          png_handle_iTXt(png_ptr, info_ptr, length);
+ #endif
+ 
++#ifdef PNG_READ_APNG_SUPPORTED
++      else if (chunk_name == png_acTL)
++         png_handle_acTL(png_ptr, info_ptr, length);
 +
-+    if (blend_op == PNG_BLEND_OP_OVER)
-+    {
-+        if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0 &&
-+            png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) == 0)
-+        {
-+          png_warning(png_ptr, "PNG_BLEND_OP_OVER is meaningless "
-+                               "and wasteful for opaque images, ignored");
-+          blend_op = PNG_BLEND_OP_SOURCE;
-+        }
-+    }
++      else if (chunk_name == png_fcTL)
++         png_handle_fcTL(png_ptr, info_ptr, length);
 +
-+    info_ptr->next_frame_width = width;
-+    info_ptr->next_frame_height = height;
-+    info_ptr->next_frame_x_offset = x_offset;
-+    info_ptr->next_frame_y_offset = y_offset;
-+    info_ptr->next_frame_delay_num = delay_num;
-+    info_ptr->next_frame_delay_den = delay_den;
-+    info_ptr->next_frame_dispose_op = dispose_op;
-+    info_ptr->next_frame_blend_op = blend_op;
++      else if (chunk_name == png_fdAT)
++         png_handle_fdAT(png_ptr, info_ptr, length);
++#endif
 +
-+    info_ptr->valid |= PNG_INFO_fcTL;
+       else
+          png_handle_unknown(png_ptr, info_ptr, length,
+             PNG_HANDLE_CHUNK_AS_DEFAULT);
+@@ -254,6 +268,72 @@
+ }
+ #endif /* SEQUENTIAL_READ */
+ 
++#ifdef PNG_READ_APNG_SUPPORTED
++void PNGAPI
++png_read_frame_head(png_structp png_ptr, png_infop info_ptr)
++{
++    png_byte have_chunk_after_DAT; /* after IDAT or after fdAT */
 +
-+    return (1);
-+}
++    png_debug(0, "Reading frame head");
 +
-+void /* PRIVATE */
-+png_ensure_fcTL_is_valid(png_structp png_ptr,
-+    png_uint_32 width, png_uint_32 height,
-+    png_uint_32 x_offset, png_uint_32 y_offset,
-+    png_uint_16 delay_num, png_uint_16 delay_den,
-+    png_byte dispose_op, png_byte blend_op)
-+{
-+    if (width > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid width in fcTL (> 2^31-1)");
-+    if (height > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid height in fcTL (> 2^31-1)");
-+    if (x_offset > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid x_offset in fcTL (> 2^31-1)");
-+    if (y_offset > PNG_UINT_31_MAX)
-+        png_error(png_ptr, "invalid y_offset in fcTL (> 2^31-1)");
-+    if (width + x_offset > png_ptr->first_frame_width ||
-+        height + y_offset > png_ptr->first_frame_height)
-+        png_error(png_ptr, "dimensions of a frame are greater than "
-+                           "the ones in IHDR");
++    if ((png_ptr->mode & PNG_HAVE_acTL) == 0)
++        png_error(png_ptr, "attempt to png_read_frame_head() but "
++                           "no acTL present");
 +
-+    if (dispose_op != PNG_DISPOSE_OP_NONE &&
-+        dispose_op != PNG_DISPOSE_OP_BACKGROUND &&
-+        dispose_op != PNG_DISPOSE_OP_PREVIOUS)
-+        png_error(png_ptr, "invalid dispose_op in fcTL");
++    /* do nothing for the main IDAT */
++    if (png_ptr->num_frames_read == 0)
++        return;
 +
-+    if (blend_op != PNG_BLEND_OP_SOURCE &&
-+        blend_op != PNG_BLEND_OP_OVER)
-+        png_error(png_ptr, "invalid blend_op in fcTL");
++    png_read_reset(png_ptr);
++    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
++    png_ptr->mode &= ~PNG_HAVE_fcTL;
 +
-+    PNG_UNUSED(delay_num)
-+    PNG_UNUSED(delay_den)
-+}
++    have_chunk_after_DAT = 0;
++    for (;;)
++    {
++        png_uint_32 length = png_read_chunk_header(png_ptr);
 +
-+png_uint_32 PNGAPI
-+png_set_first_frame_is_hidden(png_structp png_ptr, png_infop info_ptr,
-+                              png_byte is_hidden)
-+{
-+    png_debug(1, "in png_first_frame_is_hidden()");
++        if (png_ptr->chunk_name == png_IDAT)
++        {
++            /* discard trailing IDATs for the first frame */
++            if (have_chunk_after_DAT != 0 || png_ptr->num_frames_read > 1)
++                png_error(png_ptr, "png_read_frame_head(): out of place IDAT");
++            png_crc_finish(png_ptr, length);
++        }
 +
-+    if (png_ptr == NULL)
-+        return 0;
++        else if (png_ptr->chunk_name == png_fcTL)
++        {
++            png_handle_fcTL(png_ptr, info_ptr, length);
++            have_chunk_after_DAT = 1;
++        }
 +
-+    if (is_hidden != 0)
-+        png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
-+    else
-+        png_ptr->apng_flags &= ~PNG_FIRST_FRAME_HIDDEN;
++        else if (png_ptr->chunk_name == png_fdAT)
++        {
++            png_ensure_sequence_number(png_ptr, length);
 +
-+    PNG_UNUSED(info_ptr)
++            /* discard trailing fdATs for frames other than the first */
++            if (have_chunk_after_DAT == 0 && png_ptr->num_frames_read > 1)
++                png_crc_finish(png_ptr, length - 4);
++            else if(png_ptr->mode & PNG_HAVE_fcTL)
++            {
++                png_ptr->idat_size = length - 4;
++                png_ptr->mode |= PNG_HAVE_IDAT;
 +
-+    return 1;
++                break;
++            }
++            else
++                png_error(png_ptr, "png_read_frame_head(): out of place fdAT");
++        }
++        else
++        {
++            png_warning(png_ptr, "Skipped (ignored) a chunk "
++                                 "between APNG chunks");
++            png_crc_finish(png_ptr, length);
++        }
++    }
 +}
-+#endif /* APNG */
++#endif /* READ_APNG */
 +
- #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
- static png_byte
- check_location(png_const_structrp png_ptr, int location)
-Index: pngrutil.c
-===================================================================
---- pngrutil.c
-+++ pngrutil.c
+ /* Optional call to update the users info_ptr structure */
+ void PNGAPI
+ png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
+diff -Nur libpng-1.6.22.orig/pngrutil.c libpng-1.6.22/pngrutil.c
+--- libpng-1.6.22.orig/pngrutil.c	2016-05-26 05:41:46.000000000 +0200
++++ libpng-1.6.22/pngrutil.c	2016-10-01 00:22:37.033394016 +0200
 @@ -855,6 +855,11 @@
     filter_type = buf[11];
     interlace_type = buf[12];
@@ -1428,10 +1154,271 @@ Index: pngrutil.c
 +#endif /* PROGRESSIVE_READ */
 +#endif /* READ_APNG */
  #endif /* READ */
-Index: pngwutil.c
-===================================================================
---- pngwutil.c
-+++ pngwutil.c
+diff -Nur libpng-1.6.22.orig/pngset.c libpng-1.6.22/pngset.c
+--- libpng-1.6.22.orig/pngset.c	2016-05-26 05:41:46.000000000 +0200
++++ libpng-1.6.22/pngset.c	2016-10-01 00:22:37.033394016 +0200
+@@ -241,6 +241,11 @@
+    info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
+ 
+    info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
++
++#ifdef PNG_APNG_SUPPORTED
++   /* for non-animated png. this may be overwritten from an acTL chunk later */
++   info_ptr->num_frames = 1;
++#endif
+ }
+ 
+ #ifdef PNG_oFFs_SUPPORTED
+@@ -1094,6 +1099,146 @@
+ }
+ #endif /* sPLT */
+ 
++#ifdef PNG_APNG_SUPPORTED
++png_uint_32 PNGAPI
++png_set_acTL(png_structp png_ptr, png_infop info_ptr,
++    png_uint_32 num_frames, png_uint_32 num_plays)
++{
++    png_debug1(1, "in %s storage function", "acTL");
++
++    if (png_ptr == NULL || info_ptr == NULL)
++    {
++        png_warning(png_ptr,
++                    "Call to png_set_acTL() with NULL png_ptr "
++                    "or info_ptr ignored");
++        return (0);
++    }
++    if (num_frames == 0)
++    {
++        png_warning(png_ptr,
++                    "Ignoring attempt to set acTL with num_frames zero");
++        return (0);
++    }
++    if (num_frames > PNG_UINT_31_MAX)
++    {
++        png_warning(png_ptr,
++                    "Ignoring attempt to set acTL with num_frames > 2^31-1");
++        return (0);
++    }
++    if (num_plays > PNG_UINT_31_MAX)
++    {
++        png_warning(png_ptr,
++                    "Ignoring attempt to set acTL with num_plays > 2^31-1");
++        return (0);
++    }
++
++    info_ptr->num_frames = num_frames;
++    info_ptr->num_plays = num_plays;
++
++    info_ptr->valid |= PNG_INFO_acTL;
++
++    return (1);
++}
++
++/* delay_num and delay_den can hold any 16-bit values including zero */
++png_uint_32 PNGAPI
++png_set_next_frame_fcTL(png_structp png_ptr, png_infop info_ptr,
++    png_uint_32 width, png_uint_32 height,
++    png_uint_32 x_offset, png_uint_32 y_offset,
++    png_uint_16 delay_num, png_uint_16 delay_den,
++    png_byte dispose_op, png_byte blend_op)
++{
++    png_debug1(1, "in %s storage function", "fcTL");
++
++    if (png_ptr == NULL || info_ptr == NULL)
++    {
++        png_warning(png_ptr,
++                    "Call to png_set_fcTL() with NULL png_ptr or info_ptr "
++                    "ignored");
++        return (0);
++    }
++
++    png_ensure_fcTL_is_valid(png_ptr, width, height, x_offset, y_offset,
++                             delay_num, delay_den, dispose_op, blend_op);
++
++    if (blend_op == PNG_BLEND_OP_OVER)
++    {
++        if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0 &&
++            png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) == 0)
++        {
++          png_warning(png_ptr, "PNG_BLEND_OP_OVER is meaningless "
++                               "and wasteful for opaque images, ignored");
++          blend_op = PNG_BLEND_OP_SOURCE;
++        }
++    }
++
++    info_ptr->next_frame_width = width;
++    info_ptr->next_frame_height = height;
++    info_ptr->next_frame_x_offset = x_offset;
++    info_ptr->next_frame_y_offset = y_offset;
++    info_ptr->next_frame_delay_num = delay_num;
++    info_ptr->next_frame_delay_den = delay_den;
++    info_ptr->next_frame_dispose_op = dispose_op;
++    info_ptr->next_frame_blend_op = blend_op;
++
++    info_ptr->valid |= PNG_INFO_fcTL;
++
++    return (1);
++}
++
++void /* PRIVATE */
++png_ensure_fcTL_is_valid(png_structp png_ptr,
++    png_uint_32 width, png_uint_32 height,
++    png_uint_32 x_offset, png_uint_32 y_offset,
++    png_uint_16 delay_num, png_uint_16 delay_den,
++    png_byte dispose_op, png_byte blend_op)
++{
++    if (width > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid width in fcTL (> 2^31-1)");
++    if (height > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid height in fcTL (> 2^31-1)");
++    if (x_offset > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid x_offset in fcTL (> 2^31-1)");
++    if (y_offset > PNG_UINT_31_MAX)
++        png_error(png_ptr, "invalid y_offset in fcTL (> 2^31-1)");
++    if (width + x_offset > png_ptr->first_frame_width ||
++        height + y_offset > png_ptr->first_frame_height)
++        png_error(png_ptr, "dimensions of a frame are greater than "
++                           "the ones in IHDR");
++
++    if (dispose_op != PNG_DISPOSE_OP_NONE &&
++        dispose_op != PNG_DISPOSE_OP_BACKGROUND &&
++        dispose_op != PNG_DISPOSE_OP_PREVIOUS)
++        png_error(png_ptr, "invalid dispose_op in fcTL");
++
++    if (blend_op != PNG_BLEND_OP_SOURCE &&
++        blend_op != PNG_BLEND_OP_OVER)
++        png_error(png_ptr, "invalid blend_op in fcTL");
++
++    PNG_UNUSED(delay_num)
++    PNG_UNUSED(delay_den)
++}
++
++png_uint_32 PNGAPI
++png_set_first_frame_is_hidden(png_structp png_ptr, png_infop info_ptr,
++                              png_byte is_hidden)
++{
++    png_debug(1, "in png_first_frame_is_hidden()");
++
++    if (png_ptr == NULL)
++        return 0;
++
++    if (is_hidden != 0)
++        png_ptr->apng_flags |= PNG_FIRST_FRAME_HIDDEN;
++    else
++        png_ptr->apng_flags &= ~PNG_FIRST_FRAME_HIDDEN;
++
++    PNG_UNUSED(info_ptr)
++
++    return 1;
++}
++#endif /* APNG */
++
+ #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+ static png_byte
+ check_location(png_const_structrp png_ptr, int location)
+diff -Nur libpng-1.6.22.orig/pngstruct.h libpng-1.6.22/pngstruct.h
+--- libpng-1.6.22.orig/pngstruct.h	2016-05-26 05:41:45.000000000 +0200
++++ libpng-1.6.22/pngstruct.h	2016-10-01 00:22:37.033394016 +0200
+@@ -403,6 +403,27 @@
+    png_byte filter_type;
+ #endif
+ 
++#ifdef PNG_APNG_SUPPORTED
++   png_uint_32 apng_flags;
++   png_uint_32 next_seq_num;         /* next fcTL/fdAT chunk sequence number */
++   png_uint_32 first_frame_width;
++   png_uint_32 first_frame_height;
++
++#ifdef PNG_READ_APNG_SUPPORTED
++   png_uint_32 num_frames_read;      /* incremented after all image data of */
++                                     /* a frame is read */
++#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
++   png_progressive_frame_ptr frame_info_fn; /* frame info read callback */
++   png_progressive_frame_ptr frame_end_fn;  /* frame data read callback */
++#endif
++#endif
++
++#ifdef PNG_WRITE_APNG_SUPPORTED
++   png_uint_32 num_frames_to_write;
++   png_uint_32 num_frames_written;
++#endif
++#endif /* APNG */
++
+ /* New members added in libpng-1.2.0 */
+ 
+ /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+diff -Nur libpng-1.6.22.orig/pngwrite.c libpng-1.6.22/pngwrite.c
+--- libpng-1.6.22.orig/pngwrite.c	2016-05-26 05:41:46.000000000 +0200
++++ libpng-1.6.22/pngwrite.c	2016-10-01 00:22:37.033394016 +0200
+@@ -128,6 +128,10 @@
+        * the application continues writing the PNG.  So check the 'invalid'
+        * flag here too.
+        */
++#ifdef PNG_WRITE_APNG_SUPPORTED
++   if ((info_ptr->valid & PNG_INFO_acTL) != 0)
++      png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
++#endif
+ #ifdef PNG_GAMMA_SUPPORTED
+ #  ifdef PNG_WRITE_gAMA_SUPPORTED
+       if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+@@ -360,6 +364,11 @@
+    if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+       png_error(png_ptr, "No IDATs written into file");
+ 
++#ifdef PNG_WRITE_APNG_SUPPORTED
++   if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
++      png_error(png_ptr, "Not enough frames written");
++#endif
++
+ #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+    if (png_ptr->num_palette_max > png_ptr->num_palette)
+       png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
+@@ -2380,4 +2389,42 @@
+ }
+ #endif /* SIMPLIFIED_WRITE_STDIO */
+ #endif /* SIMPLIFIED_WRITE */
++
++#ifdef PNG_WRITE_APNG_SUPPORTED
++void PNGAPI
++png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
++    png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
++    png_uint_32 x_offset, png_uint_32 y_offset,
++    png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
++    png_byte blend_op)
++{
++    png_debug(1, "in png_write_frame_head");
++
++    /* there is a chance this has been set after png_write_info was called,
++    * so it would be set but not written. is there a way to be sure? */
++    if ((info_ptr->valid & PNG_INFO_acTL) == 0)
++        png_error(png_ptr, "png_write_frame_head(): acTL not set");
++
++    png_write_reset(png_ptr);
++
++    png_write_reinit(png_ptr, info_ptr, width, height);
++
++    if ((png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) == 0 ||
++        png_ptr->num_frames_written != 0)
++        png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
++                       delay_num, delay_den, dispose_op, blend_op);
++
++    PNG_UNUSED(row_pointers)
++}
++
++void PNGAPI
++png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
++{
++    png_debug(1, "in png_write_frame_tail");
++
++    png_ptr->num_frames_written++;
++
++    PNG_UNUSED(info_ptr)
++}
++#endif /* WRITE_APNG */
+ #endif /* WRITE */
+diff -Nur libpng-1.6.22.orig/pngwutil.c libpng-1.6.22/pngwutil.c
+--- libpng-1.6.22.orig/pngwutil.c	2016-05-26 05:41:46.000000000 +0200
++++ libpng-1.6.22/pngwutil.c	2016-10-01 00:22:37.033394016 +0200
 @@ -817,6 +817,11 @@
     /* Write the chunk */
     png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
@@ -1599,10 +1586,9 @@ Index: pngwutil.c
 +}
 +#endif /* WRITE_APNG */
  #endif /* WRITE */
-Index: scripts/symbols.def
-===================================================================
---- scripts/symbols.def
-+++ scripts/symbols.def
+diff -Nur libpng-1.6.22.orig/scripts/symbols.def libpng-1.6.22/scripts/symbols.def
+--- libpng-1.6.22.orig/scripts/symbols.def	2016-05-26 05:41:46.000000000 +0200
++++ libpng-1.6.22/scripts/symbols.def	2016-10-01 00:22:37.033394016 +0200
 @@ -250,3 +250,23 @@
   png_get_palette_max @243
   png_set_option @244