Similar to the desktop version, use a light gray background
color for the Calc header cells.
There was already code in place to draw darker gray background
to highlight the header cell when a cell in that row/column is
selected.
(The actually highlighted header cell didn't wasn't always the
correct one in a quick test, but that's independent of this change.)
Adapt that to always fill the rectangle, but use a lighter gray
(lower alpha value) when not selected.
Use a separate `Paint` object for the frame (stroke).
Set the frame color and text color to black instead of gray, for
better contrast to the light gray fill/background.
Change-Id: I0490811e928ebd1b3840242fc1aa4682b2786b00
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/159989
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Michael Weghorn
d134615570
