fix(oiiotool): don't propagate unsupported channels #3838
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Fixes 3837
oiiotool already attempted to trim extra channels when outputting to a
format that can't support it. It correctly handled the two common
cases:
* More than 4 channels for formats that don't have
`supports("nchannels")` will drop after the first 4 channels.
* More than 3 channels for formats that don't have `supports("alpha")`
will drop after the first 3 channels.
But this omits an interesting (but rare) corner case: a 4 channel file
where the last channel is NOT alpha, and the output file supports an
alpha channel but not arbitrary channels. A concrete example might be
an input file that is exr with channels R, G, B, Z, writing to a PNG
file (which can support RGB or RGBA). We wouldn't want to write what
appears to be an RGBA file if that last channel isn't really alpha.
Also, noticed that oiiotool --chnames didn't properly clear the
alpha_channel and z_channel flags, which is important if the new
channel lists drop one of those channels.
lgritz
merged commit dce61b3
into
AcademySoftwareFoundation:master
19 of 20 checks passed
lgritz
added a commit
to lgritz/OpenImageIO
that referenced
this pull request
May 15, 2023
…oundation#3838) Fixes AcademySoftwareFoundation#3837 oiiotool already attempted to trim extra channels when outputting to a format that can't support it. It correctly handled the two common cases: * More than 4 channels for formats that don't have `supports("nchannels")` will drop after the first 4 channels. * More than 3 channels for formats that don't have `supports("alpha")` will drop after the first 3 channels. But this omits an interesting (but rare) corner case: a 4 channel file where the last channel is NOT alpha, and the output file supports an alpha channel but not arbitrary channels. A concrete example might be an input file that is exr with channels R, G, B, Z, writing to a PNG file (which can support RGB or RGBA). We wouldn't want to write what appears to be an RGBA file if that last channel isn't really alpha. Also, noticed that oiiotool --chnames didn't properly clear the alpha_channel and z_channel flags, which is important if the new channel lists drop one of those channels.
lgritz
added a commit
to lgritz/OpenImageIO
that referenced
this pull request
Jun 7, 2023
…oundation#3838) Fixes AcademySoftwareFoundation#3837 oiiotool already attempted to trim extra channels when outputting to a format that can't support it. It correctly handled the two common cases: * More than 4 channels for formats that don't have `supports("nchannels")` will drop after the first 4 channels. * More than 3 channels for formats that don't have `supports("alpha")` will drop after the first 3 channels. But this omits an interesting (but rare) corner case: a 4 channel file where the last channel is NOT alpha, and the output file supports an alpha channel but not arbitrary channels. A concrete example might be an input file that is exr with channels R, G, B, Z, writing to a PNG file (which can support RGB or RGBA). We wouldn't want to write what appears to be an RGBA file if that last channel isn't really alpha. Also, noticed that oiiotool --chnames didn't properly clear the alpha_channel and z_channel flags, which is important if the new channel lists drop one of those channels.
lgritz
added a commit
to imageworks/OpenImageIO
that referenced
this pull request
Jun 7, 2023
…oundation#3838) Fixes AcademySoftwareFoundation#3837 oiiotool already attempted to trim extra channels when outputting to a format that can't support it. It correctly handled the two common cases: * More than 4 channels for formats that don't have `supports("nchannels")` will drop after the first 4 channels. * More than 3 channels for formats that don't have `supports("alpha")` will drop after the first 3 channels. But this omits an interesting (but rare) corner case: a 4 channel file where the last channel is NOT alpha, and the output file supports an alpha channel but not arbitrary channels. A concrete example might be an input file that is exr with channels R, G, B, Z, writing to a PNG file (which can support RGB or RGBA). We wouldn't want to write what appears to be an RGBA file if that last channel isn't really alpha. Also, noticed that oiiotool --chnames didn't properly clear the alpha_channel and z_channel flags, which is important if the new channel lists drop one of those channels.
birsoyo
pushed a commit
to birsoyo/oiio
that referenced
this pull request
Jun 8, 2023
…oundation#3838) Fixes AcademySoftwareFoundation#3837 oiiotool already attempted to trim extra channels when outputting to a format that can't support it. It correctly handled the two common cases: * More than 4 channels for formats that don't have `supports("nchannels")` will drop after the first 4 channels. * More than 3 channels for formats that don't have `supports("alpha")` will drop after the first 3 channels. But this omits an interesting (but rare) corner case: a 4 channel file where the last channel is NOT alpha, and the output file supports an alpha channel but not arbitrary channels. A concrete example might be an input file that is exr with channels R, G, B, Z, writing to a PNG file (which can support RGB or RGBA). We wouldn't want to write what appears to be an RGBA file if that last channel isn't really alpha. Also, noticed that oiiotool --chnames didn't properly clear the alpha_channel and z_channel flags, which is important if the new channel lists drop one of those channels.
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Fixes #3837
oiiotool already attempted to trim extra channels when outputting to a format that can't support it. It correctly handled the two common cases:
supports("nchannels")will drop after the first 4 channels.supports("alpha")will drop after the first 3 channels.But this omits an interesting (but rare) corner case: a 4 channel file where the last channel is NOT alpha, and the output file supports an alpha channel but not arbitrary channels. A concrete example might be an input file that is exr with channels R, G, B, Z, writing to a PNG file (which can support RGB or RGBA). We wouldn't want to write what appears to be an RGBA file if that last channel isn't really alpha.
Also, noticed that oiiotool --chnames didn't properly clear the alpha_channel and z_channel flags, which is important if the new channel lists drop one of those channels.