After Dirk Farin had another look in the specs, it turns out that "mif1"
is actually allowed as major brand for HEIF. Also adding "msf1" which is
the equivalent for image sequences.
Just looking for "ftyp" would also match other ISOBMFF files (.mov or
.mp4 files for instance). These are the possible 4-byte "brand" code
which can follow "ftyp", as listed by Dirk Farin from libheif.
I add the "mif1" brand, as I encountered some files using this magic
(even though this should normally not be valid apparently, yet the file
loaded fine in GIMP).
This is not perfect as the standard allows potentially very big box
headers, in which case 8 bytes (the "largesize" slot) may be inserted
between "ftyp" and the brand, as I understand it. But this is actually
unlikely enough to probably never happen (the compatible brands list
would have to be huuuge, as it looks like this is the only extendable
part in a ftyp box). So let's assume this just never happens.
See also: https://github.com/strukturag/libheif/issues/83
Adding a magic number for HEIC/HEIF, which would allow to discard
obvious non-HEIC images even with the wrong extension.
Note: it looks like this magic number would also match more generically
other ISO base media file format (ISOBMFF) formats, like .mov or .mp4
files. I am enquiring for better magic but for now, this is better than
nothing.
There is something broken in the obscure "text_column" and
"pixbuf_column" code in GtkIconView, and I don't have the nerve to
debug it.
Enable opening an image on activation (double click).
Current code was only taking into account cancelation, so we could end
with weird plug-in return:
> HEIF/HEIC plug-in returned SUCCESS but did not return an image
Instead properly set an error status, and echo back the error from the
plug-in or libheif.
Thanks a lot to Dirk for contributing this, added him to AUTHORS.
Import the code from https://github.com/strukturag/heif-gimp-plugin.git
as of today. Merged the files into a single-file plug-in. Changed
the code a lot to match our coding style, but only formatting,
no logic changes.
Still uses deprecated GimpDrawable API and no GIO, but I wanted to do
actual code changes separately from the initial import. Also disabled
metadata support because updating that to GimpMetadata was too much
for the initial import.
