Re: [Openexr-devel] rgb with Rgba interface?

[Florian Kainz]

Yes, it is possible.  The RgbaOutputFile constructors have
an optional rgbaChannels argument.  If you open your file like
this:

    RgbaOutputFile file ("foo.exr", width, height, WRITE_RGB);

then the file will contain no alpha channel, and you don't have
to initialize the alpha channel of your frame buffer. (The RGBA
interface supports any combination of R, G, B and A; for example,
WRITE_R | WRITE_A produces a file that has only a red and an
alpha channel.)

If you use the RGBA interface to read an RGB-only file, then
the alpha channel of your frame buffer will be filled with
1.0 (opaque).

Florian


Kai-Uwe Behrmann wrote:
> Hi list,
>
> is saving of rgb images without alpha channel possible with the Rgba 
> interface in OpenEXR?
>
> In Imf::FrameBuffer fb are only the R, G and B channels inserted. But the 
> result looks bad. The CinePaint code for saving without alpha is as well 
> not active.
>
> regards
> Kai-Uwe Behrmann
>                                 + development for color management 
>                                 + imaging / panoramas
>                                 + email: address@hidden
>                                 + http://www.behrmann.name
>
>
>
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