Bugfix - clipping ranges made less restrictive as, after transformation

between original data range, data-type range, and texture (0-1) range,
16 bit data can become inaccurate for mask images.

fsl/fsleyes/displaycontext/maskopts.py

@@ -54,7 +54,7 @@ class MaskOpts(volumeopts.Nifti1Opts):
             self.dataMax = float(overlay.data.max())
 
         dRangeLen    = abs(self.dataMax - self.dataMin)
-        dMinDistance = dRangeLen / 10000.0
+        dMinDistance = dRangeLen / 100.0
 
         #################
         # This is a hack.

fsl/fsleyes/displaycontext/vectoropts.py

@@ -148,7 +148,7 @@ class VectorOpts(volumeopts.Nifti1Opts):
         # we add an offset allowing the user
         # to configure the overlay such that
         # no voxels are clipped.
-        distance = (maxval - minval) / 10000.0
+        distance = (maxval - minval) / 100.0
 
         self.clippingRange.xmin =  minval - distance
         self.clippingRange.xmax =  maxval + distance

fsl/fsleyes/displaycontext/volumeopts.py

@@ -793,7 +793,7 @@ class VolumeOpts(Nifti1Opts):
         # a small offset to the clipping limits
         # so the user can configure the scene such
         # that no values are clipped.
-        distance = abs(dmax - dmin) / 10000.0
+        distance = abs(dmax - dmin) / 100.0
 
         self.clippingRange.xmin = dmin - distance
         self.clippingRange.xmax = dmax + distance