= FreeImage Ruby Bindings

== Overview
The free-image gem provides Ruby language bindings for the
FreeImage[http://freeimage.sourceforge.net/] library.  It is free software,
released under the MIT License.

FreeImage is an light-weight, open source image manipulation library that
supports many popular graphics image {formats}[rdoc-ref:FreeImage.formats]
such as PNG, JPEG, GIF, BMP, and TIFF.

We think FreeImage is a great library for applications that need to read, write,
create and modify images and thumbnails because:

* Its easy to use
* Its supports almost all popular image formats
* Its a light-weight alternative to larger libraries such as ImageMagick,
  supporting basic manipulation functions but not advanced functionality
* Its cross-platform
* The ruby bindings are implemented using FFI, so work across all Ruby
  implementations and do not have to be compiled
* Its much more comprehensive than ImageScience
* Has comprehensive documentation

Note that FreeImage is not the right library for you if you need:
* Advanced image processing operations such as convolution and transforms
* Bitmap drawing
* Vector graphics

== Installation
free-image requires Ruby 1.8.7 or higher.  The easiest way to install
free-image is via Ruby Gems.  To install:

 gem install free-image

== Getting Started
Getting started is easy - first work through the examples in the cookbook[rdoc-ref:cookbook.rdoc].
Once you've done that, the refer to rdocs for extensive documentation.

== Memory Management
Opening and working with images consumes some memory.  Generally you won't have to
worry about this.  When an image goes out of scope, it will be garbage collected
and the underlying image memory will be freed.

Having said that, \FreeImage also lets you control when the memory is freed.
Any method that creates a new image also takes a block.  When the block finishes,
the underlying image memory is freed.  This works the same way as the File.open
method.  For example:

  FreeImage::Bitmap.open('images/lena.png') do |image|
    thumbnail = image.make_thumbail do |thumbail|
      thumbnail.save('images/thumbnail.png', :png)
    end
  end

When the inner block finishes the thumbnail image is freed and when the outer
block finished the lena image is freed.

If you need even more control, you can  use FreeImage::Bitmap#free which frees 
the underlying image.  Be careful though - once the image is freed further usage
of it will result in a segmentation fault.

== Implementation Status
The FreeImage API is divided into multiple parts.  As summarized below, the Ruby ffi
bindings currently implement a subset of the available api. Patches are welcome to
extend the coverage.

=== Bitmap functions
* General - FreeImage::Bitmap
* Bitmap management - FreeImage::Bitmap
* Bitmap information - FreeImage::Information, FreeImage::Color::Palette
* Filetype - FreeImage::File, FreeImage::IO, FreeImage::Memory
* Pixel access - FreeImage::Pixel
* Conversion - FreeImage::Conversions
* Tone mapping - Not Implemented
* ICC profile - FreeImage::ICC
* Plugin - Not Implemented
* Multipage - Not Implemented
* Memory I/O streams - FreeImage::MemoryStream
* Compression - Not Implemented
* Helper functions - FreeImage::Helper

=== Metadata Functions
* Introduction - Not Implemented
* Tag creation and destruction - Not Implemented
* Tag accessors - Not Implemented
* Metadata iterator - Not Implemented
* Metadata accessors - Not Implemented
* Metadata helper functions - Not Implemented

=== Toolkit Functions
* Rotation and flipping - FreeImage::Transforms
* Upsampling / downsampling - FreeImage::Modify
* Color manipulation - Not Implemented
* Channel processing - Not Implemented
* Copy / Paste / Composite routines - FreeImage::Modify
* Background filling - FreeImage::Modify
* Miscellaneous algorithms - FreeImage::Helper

== Documentation
Documentation is available via rdoc, and is installed automatically with the
gem.  Note that much of the documentation is directly copied from
the FreeImage API documentation available
here[http://downloads.sourceforge.net/freeimage/FreeImage3151.pdf].

free-image's online documentation is generated using Hanna.  To generate
documentation from source:

  gem install hanna-nouveau
  rake rdoc
  - or -
  rdoc -o doc/rdoc -f hanna -m "README.rdoc" lib/**/*.rb README.rdoc


== Support

If you have any questions about using free-image, please ?

== License
See LICENSE for license information.