rcicr 1.2.1

No user-facing changes. Nothing this package computes differs from 1.2.0 — no function,
argument, return value or number has changed, and no analysis script needs revisiting.

The release exists because the 1.2.0 source tree does not pass R CMD check on macOS. The
fault was in the package's own test suite, not in the package: a test asserted properties of
a rendered PNG that belong to the graphics device rather than to what was drawn, and those
properties differ between macOS and Linux. No released function was ever affected. A package
still has to pass its own checks on the platforms CRAN builds for, which is what this
release restores.

Documentation

• ?plotZmap and the README now describe what is and is not reproducible across operating
  systems. Classification images, scaling, informational value and the z-scores themselves
  are ordinary R arithmetic and do not depend on your platform — as of this release that is
  verified on Linux, macOS and Windows on every change, rather than assumed. The PNG written
  by plotZmap() is the one exception: it is drawn through a graphics device, and devices
  differ by platform in colour management and in whether they write an alpha channel, so the
  same z-map produces visibly identical figures whose files are not byte-identical.

  The practical advice, now stated in both places: compare numbers, not rendered figures,
  when checking that an analysis reproduces. A z-map image that differs pixel-for-pixel on a
  colleague's machine is not a different result. Every other PNG the package writes —
  stimuli, classification images, autoscaled classification images — is written directly
  from the pixel array and carries no such dependence.

Internal

• R CMD check now runs on macOS and Windows as well as Linux, on every change. It
  previously varied only the R version against a single platform, which is how the macOS
  failure above went unnoticed.
• The test suite pins z-map values as well as classification images, scaling and
  informational value, so cross-platform agreement of the numbers is checked rather than
  assumed.