I would like to be able to set the annotation colors to be different (e.g. strike-out "black" while keeping highlight "yellow"). I asked about this as an issue at the github page for pdftools and was told that the ui was not available, but it could be done by using advice. The code below works for me to make the strike-out black. I am wondering is there a better, more flexible, or otherwise superior way to be doing this? Thanks.
(use-package pdf-tools
:ensure t
:config
(defun pdftools-strikeout-black (oldfun loe)
(apply oldfun loe '("black")))
(advice-add 'pdf-annot-add-strikeout-markup-annotation :around
#'pdftools-strikeout-black)
)