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Comment by ca7

4 years ago

Thanks for this!

"-flatten" results in all PDF pages being rendered into a 1 page PDF output. If "-flatten" is removed, I get a multi-page PDF output as expected. Thoughts?

EDIT: "-flatten" does what it is supposed to. Delete if operating on multipage PDF.

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ca7

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mrb  4 years ago

Weird. I could swear "-flatten" didn't behave like this years ago when I last used my script. But maybe I am misremember...

Edit: haha! The "-flatten" needs to be replaced with "-alpha flatten". This way, multi-page documents are still handled correctly, and alpha transparency is also handled correctly. I just tried on this sample file with transparent images: https://tcpdf.org/files/examples/example_042.pdf

  • ca7  4 years ago

    Changing "-flatten" to "-alpha flatten" (without the double quotes) results in an error for me.

    > convert: UnrecognizedAlphaChannelOption `flatten' @ error/convert.c/ConvertImageCommand/673.

    • mrb  4 years ago

      Probably due to an older ImageMagick version. Try "-alpha remove" which should be more or less equivalent (I think)