EEG TopoPlot Head misalignment

[Link250]

Hello,
we noticed a weird behavior with the head position in a eeg_topoplot when the data points are asymmetrical or only in one corner.

In the image we are drawing two eeg topoplots with points in the top right and bottom left and our expected behavior was to see both heads overlap and contain all points instead of two smaller local heads.
This is the code used to draw them:

f = Figure()
axis = Axis(f[1, 1], aspect = 1)
xlims!(low = -2, high = 2)
ylims!(low = -2, high = 2)

data = [0, 0, 0]
pos1 = [Point2f(-1, -1), Point2f(-1.0, 0.0), Point2f(0, -1)]
pos2 = [Point2f(1, 1), Point2f(1.0, 0.0), Point2f(0, 1)]

eeg_topoplot!(axis, data, positions=pos1)
eeg_topoplot!(axis, data, positions=pos2)

Is there some workaround to keep the head location and size independent from the point locations ?
Or would it be possible to either add a way to set a position and size for the head or expose the draw_ear_nose! function ?

Thank you very much and kind regards,
Daniel, Sören, Niklas

[behinger]

1. I dont think it is possible to specify the headsize right now. It is calculated in enclosing_geometry

radius, idx = findmax(x-> norm(x .- middle), positions)

2. the head center is the mean of your plot. so if you want to keep them aligned, maybe add a

	pos1 = pos1 .- mean(pos1)
	pos2 = pos2 .- mean(pos2)

inbetween, or adjust to a common center if you want.

[Link250]

Thank you for the help,
using the formulas you provided we wrote this method to help us move and scale the head

function eegHeadMatrix(positions, center, radius)
    oldCenter = mean(positions)
    oldRadius, _ = findmax(x-> norm(x .- oldCenter), positions)
    radF = radius/oldRadius
    return Makie.Mat4f(radF, 0, 0, 0,
                       0, radF, 0, 0,
                       0, 0, 1, 0,
                       center[1]-oldCenter[1]*radF, center[2]-oldCenter[2]*radF, 0, 1)
end

We then use this matrix as model parameter for drawing the head

[behinger]

adressed in #57