Documentation/Nightly/FAQ/Extensions

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Extensions

What is an extension ?

Extensions in the Extension manager.

An extension could be seen as a delivery package bundling together one or more Slicer modules. After installing an extension, the associated modules will be presented to the user as built-in ones

The Slicer community maintains a website referred to as the Slicer Extensions Catalog to support finding, downloading and installing of extensions. Access to this website is integral to Slicer and facilitated by the Extensions Manager functionality built into the distributed program.

The Catalog classifies extensions into three levels of compliance:

1. Category 1: Fully compliant Slicer Extensions: Slicer license, open source, maintained.
2. Category 2: Open source, contact exists.
3. Category 3: All other extensions (work in progress, beta, closed source etc).

To publish extensions, developers should consider reading the following pages:

• Bundle module(s) into a Slicer extension
• Build, test, package and distribute extensions

What is the extensions catalog ?

The extensions catalog provides Slicer users with a convenient way to access the extensions previously uploaded on the extensions server:

• from within Slicer with the help of the extensions manager
• from the web: http://slicer.kitware.com/midas3/slicerappstore

Why there are no windows 32-bit extensions available ?

• Win 32 has a very limited amount of memory available to an application.
• Many registration and segmentation algorithms fail on that platform because they run out of memory, when used with state of large data.
• Some of these failures are just that, some can crash slicer. Even though the "real" failure is caused by overextending the capabilities of the hardware (in a way the users fault), it appears to the user that Slicer does not work.
• If you search the archives of slicer-users there are several such complaints until we started to discourage people to use 32 bit.

Discussion: http://massmail.spl.harvard.edu/public-archives/slicer-users/2013/006703.html

How to manually install an extension ?

1) Get revision associated with your install or built Slicer. (Menu -> Help -> About)

2) Download extension matching your Slicer revision. Select operating system, bitness and enter revision on http://slicer.kitware.com/midas3/slicerappstore

3) Extract the archive (zip or tar.gz) in a folder. You should then have a folder like:

/path/to/<slicer_revision>-<os>-<bitness>-<extension_name>-<extension_scm><extension_revision>-YYYY-MM-DD

containing folder like:

lib/Slicer-X.Y/cli-modules
lib/Slicer-X.Y/qt-loadable-modules
lib/Slicer-X.Y/qt-scripted-modules

For more details: Documentation/Nightly/Developers/DirectoryStructure

4) In the Module settings (Menu -> Edit -> Settings), add the path ending with lib/Slicer-X.Y/{cli|qt-scripted|qt-loadable}-modules

How do I associate a remote with my local extension git source directory ?

1) Start a terminal (or Git Bash on Windows)

2) Get the associated SSH remote url. Need help ?

3) Associate the remote URL with your local git source tree

git remote add origin git://github.com/<username>/MyExtension

Which remote name is expected for extension git checkout ?

When packaging an extension and generating the associated description file, the system will look for a remote named origin.

In case you get the error reported below, you will have to either rename or add a remote. Need help ?

CMake Warning at /path/to/Slicer/CMake/FindGit.cmake:144 (message):
No remote origin set for git repository: /path/to/MyExtension
Call Stack (most recent call first):
/path/to/Slicer/CMake/SlicerMacroExtractRepositoryInfo.cmake:99 (GIT_WC_INFO)
/path/to/Slicer/CMake/SlicerExtensionCPack.cmake:55 (SlicerMacroExtractRepositoryInfo)
CMakeLists.txt:25 (include)