Losing Alpha channel about refile-mini_magick HOT 8 CLOSED

Are you sure you're not converting to another format?

from refile-mini_magick.

I can confirm that uploaded transparent PNG's lose their transparency to a white background on Refile 0.6.1

from refile-mini_magick.

Is the MiniMagick version the same? Maybe while updating Refile you also updated MiniMagick (Bundler would do that automatically for you).

from refile-mini_magick.

That could surely be the case.

Gemfile.lock:

mini_magick (4.3.3)
refile (0.6.1)
      mime-types
      rest-client (~> 1.8)
      sinatra (~> 1.4.5)
    refile-fog (0.2.0)
      fog
      refile
    refile-mini_magick (0.2.0)
      mini_magick (~> 4.0)
      refile (~> 0.5)

Please note that I don't have any experience with previous versions of Refile.

from refile-mini_magick.

Could you try to compose a MiniMagick code snippet that reproduces the problem? Just copy paste the code from refile-mini_magick and fill in with specific images. Then we'll know what's the actual and expected outcome and see is the problem in Refile or MiniMagick. Which processing method does this happen on?

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I think I tracked down the problem while setting up a testcase.

The background stays transparent after resizing with this image, mini_magick 4.3.3 and the following snippet:

require 'mini_magick'

image = MiniMagick::Image.open('in.png')
image.resize '50x50'
image.gravity 'Center'
image.write 'out.png'

However, when adding the ImageMagick extent command (as in https://github.com/refile/refile-mini_magick/blob/master/lib/refile/mini_magick.rb#L81), the background of the output image will be white:

image.extent '50x50'

I'm not too comfortable with ImageMagick so I don't now if this is actually the fix and doesn't break any other stuff in the gem. Let me know if I can help in any other way.

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I have created a pull request #15 which solves the problem.

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#15 has been merged, see #15 (comment).

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