marker size different between backends

[aplavin]

The same code results in very different marker sizes with Cairo and with GL:

scatter((0,0), marker=:circle, markersize=30, label="A")
scatter!((1,0), marker='∘', markersize=80, label="B")
scatter!((0,1), marker='◇', markersize=45, label="C")
axislegend()

save("tmp_gl.png", current_figure(), backend=GLMakie)
save("tmp_cairo.png", current_figure(), backend=CairoMakie)

Cairo:

GL:

• what version of Makie are you running? (]st -m Makie) v0.22
• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie)
• What platform + GPU are you on? any

[asinghvi17]

Hmm, so on GL these get converted to signed distance fields if I recall correctly, in Cairo they are just text. We probably need to interrogate the glyph bounding box and rescale the glyph to fit the markersize in Cairo....

[jkrumbiegel]

I'm pretty sure these were consistent at some point, maybe a regression?

[ffreyer]

I think the issue here is with how GLMakie scales character markers. If you compare with text CairoMakie matches up nicely, GLMakie does not.

f,a,p = scatter((0,1), marker=Rect, markersize=45, color = :black, strokecolor = :red, strokewidth = 1)
scatter!((0,1), marker='◇', markersize=45, color = :white)

scatter!((1, 1), marker=Rect, markersize=45, color = :green, strokecolor = :red, strokewidth = 1)
text!((1, 1), text = "◇", fontsize = 45, align = (:center, :center), color = :white)

xlims!(a, -1, 2)
f

CairoMakie	GLMakie