[Vxl-maintainers] How to write code for vil that will be easy to convert to the new rewritten vil (currently mul/vil2)

[Ian S. <ian...@st...>]

At the meeting I agreed to write this short document to be included in the
vxl 1.0 release notes. It is of more general interest - so here is an early
copy.

How to write code for vil that will be easy to convert to the new rewritten
vil (currently mul/vil2)

* Read the code in mul/vil2/examples and
http://www.isbe.man.ac.uk/internal/software/c++/isbe_vxl_doc/mul/vil2/html/i
ndex.html,

* Use vil_memory_image_of<T> where possible. This wil be directly converted
to vil2_image_view<T>. Use operator(i,j) as the primary means of accessing a
pixel value. Your code will be more general if it thinks of the image in
terms of planes.

* Where you do use vil_image::get_section() and vil_image::put_section(),
wrap the resulting buffer in a vil_memory_image_of<T> before further
processing. vil2 will perform this wrapping automatically when
image::get_section() is converted to vil2_image_resource::get_view(), etc.

* Use vil_byte, vxl_uint_16, etc rather than short and unsigned char.

Alternatively
* Start using mul/vil2 now. The conversion will then just require the
running of a perl script over your code.

* Use the functions in vil2/vil2_vil.h to interface with any existing vil1
code you are using.