ITK Lecture 12: Open Source

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ITK Lecture 12Open Source Cross Platform
Software Development

• Methods in Image Analysis
• CMU Robotics Institute 16-725
• U. Pitt Bioengineering 2630
• Spring Term, 2006

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Why this lecture exists

• Successfully managing any software project is not
  an easy job
• There are a lot of tools out there that make your
  life easier
• Some weve talked about, some we havent

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CMake

• You should now be very familiar with CMake, what
  it does, and why its important
• CMake is a pretty unique tool - be sure to keep
  it in mind for future projects

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Revision control

• Allows many developers to change a common code
  base simultaneously
• Revision control of ASCII text files is easy
  binary files are harder

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CVS

• Basic CVS operations are pretty simple favorite
  GUI client is TortoiseCVS
• CVS server configuration
• pserver - relatively easy to configure on the
  client side, low security
• SSH - high security, client server
  configuration a bit trickier

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CVS benefits

• Reference version control software - many
  different client applications
• Does the job well enough to require serious
  thought before replacing

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CVS problems

• Security!
• The normal pserver security is poor at best
• SSH security is much better, but much trickier to
  use
• Some odd side effects of versioning - cant
  delete directories

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Subversion

• A newer CVS alternative, core syntax is identical
• Server configuration
• Apache web server
• svnserve - custom server
• svnserve ssh - custom server with encryption
  layer

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Subversion benefits

• More capable versioning core - directory deletion
  a legal operation
• More flexible configuration options
• Fewer security issues

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Subversion problems

• Fewer clients available
• Windows (Tortoise SVN)
• Mac (SVNx)
• Command line (most other Unixes)

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Version control interaction

• Use CVSWeb to provide HTML access to a CVS
  repository
• Subversion supports native HTML access to the
  repository
• Useful for viewing differences between file
  versions

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Code testing

• How to keep track of multiple OSs and continuous
  revision of a common codebase?
• Option 1 dont worry
• Option 2 use a testing framework

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DART

• Dashboard generator
• Coordinates builds and tests from multiple
  sources
• Client produces build/test results in XML
• Server converts XML to HTML web pages
• Supports continuous build process

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DART, cont.
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Graphics Toolkits/Libraries

• Low level OpenGL
• Scientific visualization VTK
• Other toolkits exist which are a bit more geared
  towards game development
• Plib
• Fonts Freetype FTGL

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GUI toolkits

• GLUT - an older but still useful very lightweight
  toolkit for GL development
• George wrote a C GLUT wrapper called Glutmaster
• FLTK - my personal favorite not the prettiest,
  but does everything you need

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GUI toolkits, cont.

• wxWidgets - wraps native widget sets on each
  platform therefore looks great, but fewer
  widgets than other toolkits
• QT - the luxury swiss army approach to cross
  platform GUIs expensive for proprietary devel,
  licensing issues for open source

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Documentation

• Doxygen is the gold standard
• Easy to integrate with your web server to
  automatically generate fresh documentation each
  night

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Bug tracking

• May or may not be useful depending on the number
  of users/developers you have
• First line of defense is a mailing list,
  telephone conferencing, or meetings
• If thats not adequate, try GNATS or another bug
  tracking program

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Open source licensing

• There are many options
• Dont assume theyre all the same
• Popular licenses youll likely run across
• GPL
• LGPL
• BSD

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GPL

• Possibly the most pervasive license in the Linux
  world
• Often referred to as viral
• Other licenses may be termed GPL-compatible
• Derivative code must still be GPLd

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LGPL

• Similar to the GPL, but more permissive
• Your code can use LGPL code in library form
  without having to be released under the GPL
• Common license for libraries (graphics, sound,
  etc.) as opposed to end-user programs

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BSD

• A very permissive license that essentially
  requires only an acknowledgement and waiver of
  liability
• Good for open source projects that will be used
  in close-sourced code
• ITK and VTK are released under a BSD flavored
  license

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Licensing take-home

• If you choose to open-source your code, choose
  your license carefully
• With the GPL in particular it can be easy to have
  your code get away from you
• My opinion the BSD license is the most academic
  friendly, others disagree

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What level to buy in at?

• Solo project - CVS/SVN, Doxygen documentation
• Small lab - perform manual build tests and fix
  problems via a mailing list, CVS/SVN web access
• Large lab/several labs - add automated build
  testing, GNATS bug tracking

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Unless you have a good reason, always

• Program with multiple OSs in mind
• Test on alternative OSs if practical
• Document, document, document
• Store your code using revision control
• Theres NEVER a good reason not to do this. NEVER
  EVER. You are a fool if you dont use revision
  control. Get it?