How to Draw a Custom Mark at Specific Points on the CetZ Canvas?

[jwolf]

Using marks anchor style-attribute (possible values are: center, tip, base), you should be able to control the positioning:

#canvas({
  import draw: *

  grid((-1,-1), (1,1), stroke: .25pt + gray)

  //            ,---- Direction to point at
  mark((0, 0), (1,0), symbol: "o", anchor: "center")
  //   ^--- Position of the mark
})

Gives: