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Alpha channel detection
Posted: Thu Jul 27, 2006 6:05 pm
by Guest
Hi,
is there any chance to use NConvert to detect whether or not an an alpha channel is stored in a certain image file? For example, I want to start NConvert and use
- a jpg file (cannot store an alpha channel)
- a png file (having an alpha channel)
- ...
to see if the image(s) contain(s) alpha (transparency) information.
I've read the built-in help file, but can't find what I'm looking for.
Thanks in advance!
Re: Alpha channel detection
Posted: Fri Jul 28, 2006 8:24 am
by xnview
Anonymous wrote:Hi,
is there any chance to use NConvert to detect whether or not an an alpha channel is stored in a certain image file? For example, I want to start NConvert and use
- a jpg file (cannot store an alpha channel)
- a png file (having an alpha channel)
- ...
to see if the image(s) contain(s) alpha (transparency) information.
I've read the built-in help file, but can't find what I'm looking for.
Thanks in advance!
Perhaps if you use -info
Posted: Fri Jul 28, 2006 11:56 am
by chronicsmoke
Thanks for the tip. "-info" was the first argument I used, but there is no direct indicator for an alpha channel. You can only use the Bitscount or Depth-value. "32" means: image contains alpha information, because the maximum number of available (RGB-)colors consumes the first 24-bit, the last 8-bit are used for the alpha channel, right?
Posted: Fri Jul 28, 2006 2:36 pm
by xnview
chronicsmoke wrote:Thanks for the tip. "-info" was the first argument I used, but there is no direct indicator for an alpha channel. You can only use the Bitscount or Depth-value. "32" means: image contains alpha information, because the maximum number of available (RGB-)colors consumes the first 24-bit, the last 8-bit are used for the alpha channel, right?
yes