# SmartImage 0.0.2: a sane cross-platform image compositing and thumbnail library **URL:** \ **Category:** Ruby\ **Created:** [March 30, 2010, 4:59pm UTC](https://www.ruby-forum.com/t/smartimage-0-0-2-a-sane-cross-platform-image-compositing-and-thumbnail-library/186024 "2010-03-30T16:59:12Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![murfhy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d26b3c/32.png) [@murfhy](https://www.ruby-forum.com/u/murfhy)\ **Post date:** [March 30, 2010, 4:59pm UTC](https://www.ruby-forum.com/t/smartimage-0-0-2-a-sane-cross-platform-image-compositing-and-thumbnail-library/186024/1 "2010-03-30T16:59:12Z")
SmartImage is a new, powerful, cross-platform Ruby library for compositing images and making thumbnails: gem install smartimage The above command should work on MRI (or any other platform that can load the RMagick C extension) as well as JRuby. * * * ## Background > **[GitHub - tarcieri/SmartImage: It's like a Swiss Army Knife for images, but...](https://github.com/tarcieri/smartimage)** > > It's like a Swiss Army Knife for images, but one of those tiny ones you can keep on your keychain - GitHub - tarcieri/SmartImage: It's like a Swiss Army Knife for images, but one of those t... [http://rubygems.org/gems/smartimage](http://rubygems.org/gems/smartimage) Once upon a time there was RMagick. It was powerful but it was large and confusing. Wading through a sea of documentation to figure out how to do something simple like create a thumbnail was a monumental undertaking! It was also much maligned for leaking memory, due to its API providing low level access to the C library, which included manual memory management. Then along came ImageScience. It made thumbnails and it was simple and it was good! But it was only designed for the standard Matz Ruby Interpreter. Then along came JRuby, and JRuby couldn’t run ImageScience. The JRuby people conjured up ImageVoodoo to fill in for ImageScience, but even then, it wasn’t seamless. And making thumbnails was _all_ that ImageScience and ImageVoodoo could do! ImageVoodoo added more, but it wasn’t present in the ImageScience API. I’ve often felt myself wishing that there was an alternative between these two that incorporates more powerful image processing features without drowning you in a sea of APIs. I also work on both MRI and JRuby and prefer libraries that work seamlessly across both platforms. And thus SmartImage was born. * * * ## Can it create thumbnails for my Ruby on Rails-based web application? Yes, SmartImage _CAN_ create thumbnails for your Ruby on Rails-based web application! And it can do it in the most cross-platform manner imaginable! If you are looking for a thumbnail solution that will allow you to safely migrate your web application to JRuby in the future, look no further than SmartImage. To use SmartImage in your Rails application, simply add the following to config/environment.rb: ``` config.gem 'smartimage' ``` (there is an appropriate place to put this line, BTW. The exact location is left as an exercise to the reader) That’s it! Now wherever you would like to generate thumbnails, use the following: ``` SmartImage.thumbnail_file( "path/to/input.jpg", "path/to/output.jpg", :width => 69, :height => 42 ) ``` This will generate a thumbnail which is at most 69 pixels wide (but could be smaller) and at most 42 pixels tall (but again, could be smaller). It looks at the file extension to determine the output format. We specified a .jpg so it will output a JPEG encoded image. Why could it be smaller, you ask? Because SmartImage preserves the aspect ratio of the original image by default. SmartImage allows you to set aside space of a predetermined width/height, but will ensure images are scaled with their aspect ratio preserved. Don’t like this behavior? Want to stretch out your thumbnails all weird? Just turn it off: ``` SmartImage.thumbnail_file( "path/to/input.jpg", "path/to/output.jpg", :width => 69, :height => 42, :preserve_aspect_ratio => false ) ``` Tada! Stretched-out images! Yay! * * * ## What if I want to work with raw image data instead of files? SmartImage provides both file-based and data-based methods for every API. All the APIs are the same, except file-based APIs have “\_file” on the end. For example, above we used the SmartImage.thumbnail\_file API. However, there’s also a SmartImage.thumbnail API that works on raw image data: ``` thumbnail = SmartImage.thumbnail image, :width => 69, :height => 42, :format => :jpg ``` This API produces a thumbnail in-memory from the given input image, also in-memory. We’ve requested a .jpg thumbnail, with a max width of 69 and a max height of 42. If an image format isn’t specified, the default is PNG. * * * ## What backends are supported? SmartImage works by implementing a platform-specific SmartImage::Canvas class that encompasses all of the low level image manipulation primitives. Two such canvases are currently available: - SmartImage::RMagickCanvas: a canvas backend based on the RMagick gem - SmartImage::JavaCanvas: a canvas backend based on Java AWT/Graphics2D APIs * * * ## What else can it do? SmartImage is a full-blown image compositing library which can automate tasks similar to Photoshop macros, such as assembling and compositing layers and alpha masks. For more information on these features, please see the README: > * * * ## Mailing List, Author Info You can subscribe to the SmartImage mailing list by sending email to: removed\_email\_address@domain.invalid SmartImage was created by Tony A… You can contact him through github or follow him on Twitter at @bascule. He also frequents IRC on freenode as tarcieri. ---
**Author:** ![murfhy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d26b3c/32.png) [@murfhy](https://www.ruby-forum.com/u/murfhy)\ **Post date:** [March 30, 2010, 5:09pm UTC](https://www.ruby-forum.com/t/smartimage-0-0-2-a-sane-cross-platform-image-compositing-and-thumbnail-library/186024/2 "2010-03-30T17:09:10Z")
Interesting. Does it correctly orient images? There is a flag in the EXIF data that tells you which orientation the picture was taken in. So if you turn your camera from landscape to portrait the flag is set. This was the thumbnail would be the right way up (even if the image file was not). ---
**Author:** ![murfhy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d26b3c/32.png) [@murfhy](https://www.ruby-forum.com/u/murfhy)\ **Post date:** [March 30, 2010, 6:20pm UTC](https://www.ruby-forum.com/t/smartimage-0-0-2-a-sane-cross-platform-image-compositing-and-thumbnail-library/186024/3 "2010-03-30T18:20:01Z")
On Tue, Mar 30, 2010 at 9:08 AM, Peter H. \< removed\_email\_address@domain.invalid\> wrote: > Interesting. Does it correctly orient images? There is a flag in the EXIF > data that tells you which orientation the picture was taken in. So if you > turn your camera from landscape to portrait the flag is set. This was the > thumbnail would be the right way up (even if the image file was not). Offhand I can’t say… I’d need to write a spec for it. I would like to provide consistent semantics across all of the backend canvas libraries (RMagick and Java AWT/Graphics2D for the time being) and that’s something worth checking out.