Imported from libpng-1.0.9beta6.tar
diff --git a/pngwrite.c b/pngwrite.c
index f1f1d3a..b004a06 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@
/* pngwrite.c - general routines to write a PNG file
*
- * libpng 1.0.9beta5 - December 15, 2000
+ * libpng 1.0.9beta6 - December 18, 2000
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -28,6 +28,13 @@
if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
{
png_write_sig(png_ptr); /* write PNG signature */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
+ {
+ png_warning(png_ptr,"MNG features are not allowed in a PNG datastream\n");
+ png_ptr->mng_features_permitted=0;
+ }
+#endif
/* write IHDR information. */
png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
@@ -774,6 +781,15 @@
png_do_write_transformations(png_ptr);
#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ /* Write filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not write a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
{
@@ -977,6 +993,11 @@
png_set_filter(png_structp png_ptr, int method, int filters)
{
png_debug(1, "in png_set_filter\n");
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+ (method == PNG_INTRAPIXEL_DIFFERENCING))
+ method = PNG_FILTER_TYPE_BASE;
+#endif
if (method == PNG_FILTER_TYPE_BASE)
{
switch (filters & (PNG_ALL_FILTERS | 0x07))