On my mac, ImageMagick "convert test.png test.tif" also results in what appears
to be a black image.
And using ImageMagick's "identify -verbose", I see these stats:
Alpha:
min: 0 (0)
max: 0 (0)
mean: 0 (0)
standard deviation: 0 (0)
kurtosis: -3
skewness: 0
entropy: 0
Are you *sure* that the alpha channel isn't really 0 everywhere?
> On Feb 8, 2019, at 11:55 AM, Larry Gritz <[email protected]> wrote:
>
> Hmmm... it's not just "--ch", that image looks "black" (all 0.0 values) in
> all channels to all OIIO tools. (For example, `oiiotool -stats test.png`) I'm
> suspecting something in the reader rather than an issue with channel
> selection.
>
> Looking into it.
>
> -- lg
>
>
>> On Feb 8, 2019, at 11:31 AM, Stephen Parker <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Hi Larry,
>>
>> I'm on the release branch. Here is the PNG in question (attached).
>>
>> thanks
>>
>> On Fri, Feb 8, 2019 at 11:12 AM Larry Gritz <[email protected]
>> <mailto:[email protected]>> wrote:
>> Which version of OIIO?
>> And I don't suppose you can send me an example PNG that has the problem? Or
>> is it weird for every png you try?
>>
>>
>>
>>> On Feb 8, 2019, at 10:59 AM, Stephen Parker <[email protected]
>>> <mailto:[email protected]>> wrote:
>>>
>>> Hello,
>>>
>>> I'm having some trouble using oiiotool's copy channel operator. It might be
>>> user error but I wanted to check and see if it's intended behavior. I've
>>> only glanced at the code so far.
>>>
>>> My test image is a PNG (4-channel RGBA), but only has information in the
>>> Alpha. When attempting to copy the Alpha into the other 3 channels and
>>> write out an RGB image (no Alpha), I get black. Imagemagick's 'convert' did
>>> what I expected.
>>>
>>> invoked as:
>>>
>>> oiiotool input.png --ch "R=A,G=A,B=A" -o output.png
>>>
>>> I also tried using the numeric channel labels to no avail.
>>>
>>> -sp
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>>
>> --
>> Larry Gritz
>> [email protected] <mailto:[email protected]>
>>
>>
>>
>>
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>> <test.png>_______________________________________________
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>
> --
> Larry Gritz
> [email protected] <mailto:[email protected]>
>
>
>
>
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--
Larry Gritz
[email protected]
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