Re: Specifying the file format when writing to a Blob

On Wed, 5 Sep 2012, Marten Lehmann wrote:
>
> I can use writeImages() to either write to a filename like whatever.pdf
> and then the SetImageInfo() function would extract the filetype pdf from
> the extension and set image_info->magick to PDF and image_info->affirm
> to MagickTrue.
>
> I can also use a filename like pdf:- and the full output would be
> written as PDF to stdout. But as I'm using all this behind the pgmagick
> library within Python, it is not that easy to fetch the output.
>
> So what I'm really missing is a way to specify a file format when using
> writeImages() with a Blob target. With the output in the Blob, I could
> really do everything in-memory, without workarounds like fetching stdout
> or using temporary files which will be deleted after reading.
>
> Any ideas? Anything existing, that I have overseen?

You have not overseen anything.  This is a design defect in the API. 
I believe that an effective workaround would be to use the 
Magick::Image::magick() (i.e. image.magick()) method to set the format 
in the first frame of the vector/list.  This should work because the 
writer uses the current image set format from the first image in the 
list when writing.

I am adding this to the top of my TODO list and perhaps it will be 
fixed in this next release.

Bob
-- 
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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