Removed TransformerInterface

[rvanlaarhoven]

Removed the obsolete TransformerInterface. Together with it, I removed the documentation part about Extending the image loader with data transformers, which was simply an explanation on how to use the already removed ExtendedFileSystemLoader.

[makasim]

Unfortunately we can not remove it because we already released a stable version, and it is a BC break if remove it. We have to mark it as deprecated.

From the other side I dont think it is used much so we may do an exception in this particular case.
@havvg @lsmith77 wdyt?

[lsmith77]

i think its better to mark it deprecated.

[rvanlaarhoven]

Okay, just let me know what to add as the deprecated message, so I can update the pull request.

[makasim]

@rvanlaarhoven It does not matter much, just something like "It will be removed in 2.0"

[rvanlaarhoven]

Updated the pull request.

[lsmith77]

+1 from me .. will let @makasim make the final decision

[havvg]

+1 on deprecation over BC break

[makasim]

Thanks @rvanlaarhoven

[christoph-hautzinger]

i am currently upgrading from 0.x to 1.x - what was the reason to remove the transformers?
and how is the suggested way to generate preview imaegs from pdfs now? (<-- more important question ;))
thanks for answer :)

[Sander-Toonen]

I have the same question as @christoph-hautzinger. Is there an alternative way to generate thumbnails from PDFs and if so, could we add something about the removal of the TransformerInterface in UPGRADE.md?

[lucasaba]

Same question here... I'm trying to creating a custom data loader and a custom cache resolver but...it's quite messy. Is there a better way now ?