Log Message:
(..graphics/R-colorspace) Updated 2.0.1 to 2.1.1

# colorspace 2.1-1

* In the `hclwizard()` shiny app the Python export now leverages the Python
  _colorspace_ package available from PyPI at \ 
<https://pypi.org/project/colorspace/>.
  For more details see the Python package documentation at
  <https://retostauffer.github.io/python-colorspace/>.

* Improvement in `desaturate()`: In addition to previous input color specifications
  (hex strings, named colors, RGB matrices), formal S4 color objects are now
  also supported. In this case, the desaturated colors are also returned as color
  objects of the same class as the input. With this improvement, `desaturate()`
  behaves exactly analogous to the color vision deficiency emulation functions
  which had been improved in the same way in version 2.1-0 (see below).

* Try harder to preserve the names in named color vectors when transformed with
  `lighten()`, `darken()`, `adjust_transparency()`, `simulate_cvd()`, etc.
  (suggested by Matias Andina).

* Make the fixed color vision deficiency simulation in linear RGB coordinates
  (introduced in version 2.1-0) the default in the `cvd_emulator()` shiny app
  as well.

* Minor bug fixes in `hclplot()`, the automatically generated figure titles
  only use the H/L coordinates of the colors visualized. Minor fix on how
  `right` (index of colors on the right hand side of a diverging palette)
  is calculated.

* Support `n = 1` color in `diverging_hcl()` and `divergingx_hcl()` which then
  both return the neutral color in the center of the respective palette.

# colorspace 2.1-0

* Bug fix for color vision deficiency simulations in `simulate_cvd()` based
  on the work of [Machado _et al._ (2009)](https://doi.org/10.1109/TVCG.2009.113):
  Following some illustrations from the supplementary materials, the transformations
  in previous versions of the package had been applied to gamma-corrected sRGB
  coordinates directly. However, the Machado _et al._ paper implicitly relies
  on a linear RGB space (see page 1294, column 1) where their linear matrix
  transformations for simulating color vision deficiencies are applied.
  Therefore, a new argument `linear = TRUE` has been added to `simulate_cvd()`
  (and hence in `deutan()`, `protan()`, and `tritan()`) that first maps the
  provided colors to linearized RGB coordinates, applies the color vision
  deficiency transformation, and then maps back to gamma-corrected sRGB
  coordinates. Optionally, `linear = FALSE` can be used to restore the behavior
  from previous versions where the transformations are applied directly to
  the sRGB coordinates. For most colors the difference between the two
  strategies is negligible but for some highly-saturated colors it becomes
  more noticable, e.g., for red, purple, or orange. Thanks to Matthew Petroff
  for reporting this issue and to Kenneth Knoblauch for advice and guidance.

* Improvement in `simulate_cvd()` (and hence in `deutan()`, `protan()`, and
  `tritan()`): When colors are specified as hex strings or named colors, the
  sRGB coordinates after transformation are rounded appropriately to integers
  in 0-255. Previous versions implicitly took the floor rather than round of
  the coordinates.

* Support formal S4 color objects in `simulate_cvd()` (and hence in `deutan()`,
  `protan()`, and `tritan()`). In that case colors are transformed internally
  to sRGB coordinates, color vision deficiency is simulated, and then a formal
  S4 color object (of the same class as the input) is returned. This has the
  advantage that no rounding is applied as when going through hex color strings.
  Similarly, for an RGB matrix input, the output is also not rounded anymore.

* Bug fix in `scale_colour_discrete_qualitative()` (and analogously for sequential,
  diverging, and divergingx) to make sure that the scale functions can also
  be called within a function whose arguments are controlled by an outer
  function (reported by Marcelo S. Perlin).

# colorspace 2.0-3

* Added the accessible perceptual contrast algorithm (APCA) that is under
  development for the next major revision of the WCAG as an alternative
  `algorithm` in `contrast_ratio()`. See <https://github.com/Myndex/SAPC-APCA>.

* Fixed a bug in `lighten()` and `darken()` for the case when some colors
  were named (e.g., `"blue"`) rather than hex strings only. In that case
  linear RGB rather than sRGB was incorrectly used internally (reported by
  Colin Goodall).

# colorspace 2.0-2

* New function `contrast_ratio()` for computing and visualizing contrast ratios
  of pairs of colors as defined in the Web Content Accessibility Guidelines (WCAG)
  (<https://www.w3.org/TR/WCAG21/>) of the World Wide Web Consortium (W3C).