Add file transformers to the file loader

[lucasaba]

In this way, it is possible to pass an array of transformer
to the data loader.
Transformers can be used to create images for
virtually any file type.

This PR is a cleanup of previous posts and references #52.

[stof]

typo in the variable name

[stof]

btw, you should typehint the array

[lucasaba]

poke

[lsmith77]

ok this looks fine to me now.
one thing that we might want to add eventually is to add some by reference parameter to applyTransform() to stop the transform foreach. but i think that can wait.

[lsmith77]

please do not omit curly brackets

[lsmith77]

opps .. i also noticed another thing. i would prefer it if we would inject the Imagick instance .. i don't have experience with its API .. but i assume we could also call setFilename() instead of passing the absolute path to the constructor? could you do a PR to change this?

[lsmith77]

hmm actually it seems Imagine itself is using the same approach .. the Imagick OO API also seems a bit strange:
https://github.com/avalanche123/Imagine/blob/master/lib/Imagine/Imagick/Imagine.php

@avalanche123 do you have a tip for us here what would make the most sense?

[lucasaba]

You are right. It would be better. I'm checkin the API and PR the changes!

[lucasaba]

Thank you for all the corrections, informations, lessons and for your patience ;)

[lsmith77]

no problem .. thx for working through all of this. looking forward for other patches from you :)

[rvanlaak]

Great addition to the bundle! My usecase is that I want to create thumbnails of all pages, so any ideas on a PR for that? In theory it sounds simple, since the page number is hard-coded in PdfTransformer.php

[havvg]

The thing is you are creating more than one image in your case.
For itself, there is no problem with it, but well, you can't simply apply it to any PDF, which page do you want to return? You can add options for all of this, but then you would have to ensure the PDF has page X, where X is the page the thumbnail would be returned for, and you need a naming scheme to create the respective thumbnails for.

[rvanlaak]

In my usecase I already know the exact amount of pages in the PDF, so what I would like to do is create a loop in Twig and do a call to the imagine_filter every time. The PdfTransformer needs to be modified in order to accept a page number, and indeed, else return an IndexOutOfBoundException in case the page does not exists.

The TransformerInterface::apply() function only accepts one parameter, the $absolutePath. Does the interface needs to be modified in order to accept page numbers?

[havvg]

It would indeed require even more. You would need to pass in options into image_filter, to be able to pass them around - and to the transformer. Which in return would require you to have options in the routing to specifically request the correct page, which would require to modify the CacheManager, too.

Unless I'm getting it all wrong right now, I'm against such heavy changes in the 0.x version line. However, if you figure out a sensible solution, send the PR :-)

[rvanlaak]

Idea to reopen this issue , or should I create another issue for discussing the features?

[havvg]

A new one, please.