-------------------------------------------
entry variable: $curv -- absolute name curv file
def: $SUBJECTS_DIR/name/surf/$hemi.curv
-------------------------------------------
aux variable: $template -- absolute name template
def: $FSURF_DIR/average/
          $hemi.average.curvature.filled.buckner40.tif
-------------------------------------------

Single Subject Curvature

The "curv:" entry at the upper left shows the
current file loaded as curvature.  To load a
different file, select one from the "curv:"
dropdown (or use "R"), for example:

 $hemi.curv -- standard local curvature file
 $hemi.sulc -- summed local perpendic. movement
 $hemi.thickness -- vertexwise gray matter thickness

Relative name assumes same dir as above.  Home
dir of subject can be abbreviated as tilde (~).
Absolute name OK, too.  Reads either old curv or
new curv file format.  New curv format files can
also be read by read_binary_values.

Average Morph Target Template

If FSURF_DIR is defined, the standard MGH morph
target template files (Mercator projections
stored in a multi-frame .tif) will be loaded at
the bottom of the dropdown, for example:

  $hemi.average.curvature.filled.buckner40.tif

On selecting one of these tif's, a pop-up will
first appear to allow selecting one of its
frames.  Useful frames are 3 (average sulc) and 6
(average curvature).

Binary Formats

Binary oldcurv file format:
  [no magic number]
  3-byte uint vertex count
  3-byte uint face count
  2-byte short curv[vtx0]*100
  2-byte short curv[vtx1]*100
   ...
  [implicit vtx numbering -- all vtxs req'd]

Binary newcurv file format (=newarea format):
  3-byte magic number: 16777215
  4-byte int vertex count
  4-byte int face count
  4-byte int values per vertex
  4-byte float data [vtx0]
  4-byte float data [vtx1]
  ...
  [implicit vtx numbering -- all vtxs req'd]

Binary template file format (Mercator projection)
  multi-frame uncompressed .tif
  width=256, height=512
  32 bits per sample
  1 sample per pixel
