Question

I’m currently trying to code a custom image cropping system similar to other ones on the internet where a user can select a cropping area and then have their image cropped accordingly. The application is in Rails and we’re using Paperclip with Amazon S3 to store the files. I’m having a lot of trouble though getting RMagick to appropriately crop the file from S3. Here is the current code (which does not work):

   if params[:width].to_i > 0 and params[:height].to_i > 0 then       photo = Photo.find(params[:id])       image_data = Net::HTTP.get_response(URI.parse(photo.photo.url(:big))).body       orig_img = Magick::ImageList.new       orig_img.from_blob(image_data)        args = [params[:x1].to_i, params[:y1].to_i, params[:width].to_i, params[:height].to_i]       orig_img.crop!(*args)       photo.update_attributes({:photo => orig_img.to_blob})        photo.photo.reprocess!       photo.save     end 

The main problem is that the cropped image is not uploaded back to S3 through paperclip, and thus not properly cropped. Has anyone attempted something like this with paperclip before? This may not even possible, but any help would be greatly appreciated.

Answer 1

I’ve been able to solve this problem for the time being as follows:

  photo = Photo.find(params[:id])   image_data = Net::HTTP.get_response(URI.parse(photo.photo.url(:big))).body   orig_img = Magick::ImageList.new   orig_img.from_blob(image_data)    args = [params[:x1].to_i, params[:y1].to_i, params[:width].to_i, params[:height].to_i]   orig_img.crop!(*args)    tmp_img = Tempfile.new('image_data')   orig_img.format = 'png'   tmp_img.write(orig_img.to_blob)   photo.photo = tmp_img   tmp_img.close    photo.photo.reprocess!   photo.save 

The main concern here is the speed hit of creating a new temporary file, so probably we will have to create our own custom interface. Hopefully this can be a good starting point for people solving a similar issue.

EDIT: Just a quick note, Tempfile is part of the paperclip libraries.