Converting a tiff image

mikec · February 23, 2010, 10:42pm

Does anyone know of a way to convert an uploaded tiff image into a jpg
or png?

mikec · February 23, 2010, 10:59pm

Mike Chai wrote:

Does anyone know of a way to convert an uploaded tiff image into a jpg
or png?

mikec · February 23, 2010, 11:21pm

Thanks. How can I use paperclip to convert? I tried looking it up in
google but got no results.

mikec · February 24, 2010, 12:26am

On 23 Feb 2010, at 23:19, Mike C wrote:

Use :convert_options as shown here:
http://www.taknado.com/en/2009/10/01/paperclip-tweaks/
(found using “paperclip rails convert file” on google). Someone else
will be able to give you the imagemagick command parameter to convert
to jpg I hope, don’t know it by heart.

Best regards

Peter De Berdt

mikec · February 24, 2010, 12:33am

This is actually used with AttachmentFu, but has some example code for
Rmagick resizing:

github.com

kete/kete/blob/master/lib/resize_as_jpeg_when_necessary.rb#59

# from http://blog.airbladesoftware.com/2007/6/27/compressing-images-with-attachment_fu-and-rmagick
# and http://blog.airbladesoftware.com/2008/1/15/converting-image-format-when-thumbnailing
# modified to use more standard tools, i believe there was some unnecessary code in here
# basically, i'm running on the assumption that if the original is not jpeg, gif, or png
# we should convert it to jpeg
# this obviously is deeply dependent on use of AttachmentFu plugin with Rmagick
module ResizeAsJpegWhenNecessary
  unless included_modules.include? ResizeAsJpegWhenNecessary

    def self.included(klass)
      klass.send :set_callback, :before_thumbnail_saved, :before do |record|
        record.content_type = 'image/jpeg' if record.class.should_be_converted?(record.parent.filename)
      end
      klass.extend(ClassMethods)
    end

    module ClassMethods
      # https://github.com/kete/attachment_fu/blob/master/lib/technoweenie/attachment_fu.rb#L190
      #   * attachment_fu limits image content types to too narrow a view - we
      #     make it match what the user has set as configuration.

This file has been truncated. show original

Cheers,
Walter

On Wed, Feb 24, 2010 at 12:24 PM, Peter De Berdt

mikec · February 24, 2010, 12:34am

The #59 meaning the relevant line is mainly the setting of format in
line 59. There is other stuff in their you may find useful, too.

Cheers,
Walter

On Wed, Feb 24, 2010 at 12:31 PM, Walter McGinnis

mikec · February 25, 2010, 3:36pm

On Thu, 2010-02-25 at 01:29 -0800, Mike C wrote:

Thanks for the replies. I’m using paperclip, but while search I still
can’t find out how to do this. I want to convert the image to jpg/png
ONLY if it’s a tiff image. I saw processors/callbacks in paperclip but
I haven’t found any way to make a Processor that can do this for me
since I don’t know how to call Imagemagick from ruby code. Would I
need Rmagick for this and how would it play in with paperclip?

I don’t worry about it because I simply convert everything to jpg.

Of course you have the complete paperclip code so you can see how it’s
doing things and modify it for your purposes.

Craig

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mikec · November 6, 2013, 9:36am

I have only tried to convert Tiff files using the free trial package of
another Tiff converter:

I am considering to employ one to help me. Do you have any good
suggestion?

mikec · February 25, 2010, 10:30am

Thanks for the replies. I’m using paperclip, but while search I still
can’t find out how to do this. I want to convert the image to jpg/png
ONLY if it’s a tiff image. I saw processors/callbacks in paperclip but
I haven’t found any way to make a Processor that can do this for me
since I don’t know how to call Imagemagick from ruby code. Would I
need Rmagick for this and how would it play in with paperclip?

mikec · November 6, 2013, 2:49pm

On Nov 6, 2013, at 3:36 AM, arron w. wrote:

I have only tried to convert Tiff files using the free trial package of
another Tiff converter:
Implement Multi-page TIFF File Conversions in C# Programming
I am considering to employ one to help me. Do you have any good
suggestion?

Install imagemagick on your server. It’s free, and very powerful.
Converting a TIFF to another image format is as simple as this:

convert /path/to/image.tiff /path/to/output.jpg

Naturally, you can do almost anything and tweak almost anything, given
the right flags passed to the convert command. If imagemagick can’t open
or understand the file, it’s highly unlikely that it is an image at all.

Walter