Mark positioning

[arkadiuszwojcik]

In currect CeTZ implementation when we place mark at point (x,y) it is tip of mark that will occupy that position. In case on marks that are large or long it creates some issues to center in properly in the middle of line, because in most cases we would like to position mark in such way that graphical center of mark will occupy (x,y). Image below. Top part represent current mark positioning behaviour, bottom part my tweaks to place mark relative to is graphical center. Second one (mark shifted by mark_width/2) seems more intuitive I think.

[Enivex]

This has frustrated me as well, though I don't know if I was just doing something wrong.