Flickr style resizing with attachment_fu

Question

I want attachment_fu to resize my thumbnails in a similar way to how flickr, facebook and twitter handle this: If I want a 100x100 thumbnail I want the thumbnail to be exactly 100x100 with any excess cropped off so that the aspect ratio is preserved.

Any ideas?

Answer 1

My solution was to delve into the attachment_fu plugin folder (vendor/plugins) and edit the rmagick_processor.rb file. First I renamed resize_image to resize_image_internal, then added:

  def resize_image(img, size)  
    # resize_image take size in a number of formats, we just want  
    # Strings in the form of "square: WxH"  
    if (size.is_a?(String) && size =~ /^square: (\d*)x(\d*)/i) ||  
        (size.is_a?(Array) && size.first.is_a?(String) &&  
          size.first =~ /^square: (\d*)x(\d*)/i)  
        iw, ih = img.columns, img.rows
        aspect = iw.to_f / ih.to_f
        if aspect > 1
            shave_off = (iw - ih) / 2
            img.shave!(shave_off, 0)
        else
            shave_off = (ih-iw) / 2
            img.shave!(0, shave_off)
        end
        resize_image_internal(img, "#{$1}x#{$2}!")
    else  
      resize_image_internal(img, size) # Otherwise let attachment_fu handle it  
    end  
  end

I can now use 'square: 100x100' as my geometry string. Note that the above code assumes the required output is square.