Mouse Picking

using Makie

 img = rand(100, 100)
 scene = Scene(resolution = (500, 500))
 heatmap!(scene, img, scale_plot = false)
 clicks = Node(Point2f0[(0,0)])
 on(scene.events.mousebuttons) do buttons
    if ispressed(scene, Mouse.left)
        pos = to_world(scene, Point2f0(scene.events.mouseposition[]))
        push!(clicks, push!(clicks[], pos))
    end
    return
 end
 scatter!(scene, clicks, color = :red, marker = '+', markersize = 10)
 RecordEvents(scene, "output")