Text layouting tests

[ffreyer]

I don't think these tests are all that useful since they mostly repeat what Makie does internally. The problem with comparing to FreeTypeAbstraction directly (i.e. letting it render at the correct fontsize or the glyph fontsize) is that it doesn't scale characters in float steps but integer steps. So the difference between a 32px and 64px fontsize isn't a factor of 2:

img32, ext32 = renderface(font, '^', 32)
img64, ext64 = renderface(font, '^', 64)
ext32
# FontExtent{Float64}([-11.0, 11.0], [3.0, 23.0], [27.0, 32.0], [21.0, 9.0])
ext64
# FontExtent{Float64}([-21.0, 23.0], [6.0, 47.0], [54.0, 64.0], [41.0, 17.0])

It also seems to do more than just rounding up sometimes:

renderface(font, '_', 20)[2].scale
#2-element Vec2{Float64} with indices SOneTo(2):
# 12.0
#  2.0

ceil.(Int, FreeTypeAbstraction.get_extent(font, '_').scale * 20)
#2-element Vec2{Int64} with indices SOneTo(2):
# 11
#  2

[SimonDanisch]

Thank you! I guess we need to overthink the text boundingbox API some more after the next release ^^