How to get a coordinates of the square in a heatmap using Observables?

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1

I have an image (or heatmap) and I want to be able to click and find x and y indexes of clicked area using Observables. How could it be possible?

2

Assuming this is in Makie :smiley: - in that case, check out the events explanation in the docs! Basically you would lift on axis.scene.events.mousebutton, and check the value of axis.scene.events.mouseposition. This is in pixels, but you can project it to data space using Makie.project(axis.scene, :pixel, :data, axis.scene.events.mouseposition[]) or so.

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3

First part worked, thanks you!
Second part worked with:
test = Makie.project(camera(ax.scene), :pixel, :data, ax.scene.events.mouseposition[])

But! The coordinates are not correct, unfortunately.
Moreover:

  • They update even when I press on white area of the figure, while they obliviously should update only when I press the heatmap area.
  • They are float, not numeric
  • The ranges do not correspond
4

Gosh, there is no even documentation for Makie.project…

5

How I solved it:

plot, _ = pick(ax.scene)
pos = Makie.position_on_plot(plot, -1, apply_transform = false)[Vec(1, 2)]
b = Makie._pixelated_getindex(plot[1][], plot[2][], plot[3][], pos, true)
chan_i[], var_i[] = b[1], b[2]