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List:       graphicsmagick-apis
Subject:    Re: [GM-apis] R: Re: R: Re: R: Re:  understand  ImageType, ClassType and ColorspaceType
From:       Bob Friesenhahn <bfriesen () simple ! dallas ! tx ! us>
Date:       2013-04-16 14:20:26
Message-ID: alpine.GSO.2.01.1304160907020.2267 () freddy ! simplesystems ! org
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On Tue, 16 Apr 2013, maracas83@libero.it wrote:

> As always your advice is very useful.
> I'm sorry, but unfortunately I still have some doubts.
> Attached are two different images that exibits the same properties.
> ClassType=DirectClass, ImageType=BilevelType, depth=	8,
> ColorSpaceType=sRGBColorspace.
> In both cases matte() returns false.

It should not be returning false for one of your images because GM 
does claim it has an opacity channel:

% gm identify -verbose /home/bfriesen/BW_32BPP.bmp
Image: /home/bfriesen/BW_32BPP.bmp
   Format: BMP (Microsoft Windows bitmap image)
   Geometry: 48x48
   Class: DirectClass
   Type: bilevel
   Depth: 1 bits-per-pixel component
   Channel Depths:
     Gray:     1 bits
     Opacity:  1 bits
   Channel Statistics:
     Gray:
       Minimum:                     0.00 (0.0000)
       Maximum:                 65535.00 (1.0000)
       Mean:                    52763.64 (0.8051)
       Standard Deviation:      25964.52 (0.3962)
     Opacity:
       Minimum:                 65535.00 (1.0000)
       Maximum:                 65535.00 (1.0000)
       Mean:                    65535.00 (1.0000)
       Standard Deviation:          0.00 (0.0000)
   Opacity: (  0,  0,  0,255)      #000000FF

Are you absolutely sure that Magick++ returns matte() of false for 
this image?

Bob
-- 
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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