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[devel] Add comment about TODO: issue warning if user tries to premultiply

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in a nonliner colorspace.
This commit is contained in:
Glenn Randers-Pehrson 2009-11-26 11:49:37 -06:00
parent b2154ccb2b
commit 4cfdb3c095
1 changed files with 18 additions and 0 deletions
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18
pngread.c
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@ -425,6 +425,24 @@ png_read_update_info(png_structp png_ptr, png_infop info_ptr)
else
png_warning(png_ptr,
"Ignoring extra png_read_update_info() call; row buffer not reallocated");
#ifdef PNG_READ_PREMULTIPLY_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_PREMULTIPLY_ALPHA)
{
/* TO DO:
* Check for linear colorspace and if not, issue a warning.
* If gAMA is present with gamma == 1.0, it's linear.
* If iCCP is present, assume user knows what they are doing
* and it's linear.
* If gAMA is present with gamma != 1.0, it's not linear.
* If no gAMA or iCCP, assume not linear.
* If not linear do:
* png_warning(png_ptr,
* "Premultiply should only be used with gamma == 1.0");
*/
}
#endif
png_read_transform_info(png_ptr, info_ptr);
}