convert color early to avoid mesh path

[jkrumbiegel]

Fixes #2510

[MakieBot]

Compile Times benchmark

Note, that these numbers may fluctuate on the CI servers, so take them with a grain of salt. All benchmark results are based on the mean time and negative percent mean faster than the base branch. Note, that GLMakie + WGLMakie run on an emulated GPU, so the runtime benchmark is much slower. Results are from running:

using_time = @ctime using Backend
# Compile time
create_time = @ctime fig = scatter(1:4; color=1:4, colormap=:turbo, markersize=20, visible=true)
display_time = @ctime Makie.colorbuffer(display(fig))
# Runtime
create_time = @benchmark fig = scatter(1:4; color=1:4, colormap=:turbo, markersize=20, visible=true)
display_time = @benchmark Makie.colorbuffer(display(fig))

	using	create	display	create	display
GLMakie	37.20s (36.48, 38.11) 0.54+-	19.38s (18.33, 20.06) 0.56+-	17.81s (17.14, 18.48) 0.44+-	13.66ms (13.36, 14.19) 0.33+-	159.51ms (156.29, 164.29) 2.44+-
master	36.65s (35.51, 37.86) 0.77+-	19.38s (19.06, 19.79) 0.29+-	18.09s (17.57, 19.94) 0.84+-	13.70ms (13.19, 14.31) 0.36+-	162.21ms (157.08, 168.11) 3.72+-
evaluation	+1.48%, 0.55s invariant (0.83d, 0.15p, 0.66std)	-0.02%, -0.0s invariant (-0.01d, 0.99p, 0.42std)	-1.60%, -0.29s invariant (-0.43d, 0.44p, 0.64std)	-0.26%, -0.04ms invariant (-0.11d, 0.85p, 0.34std)	-1.70%, -2.71ms invariant (-0.86d, 0.14p, 3.08std)
CairoMakie	33.22s (32.46, 35.26) 0.96+-	20.32s (19.86, 20.89) 0.32+-	3.09s (3.01, 3.17) 0.05+-	15.83ms (15.52, 15.99) 0.17+-	6.14ms (5.92, 6.46) 0.17+-
master	33.26s (32.57, 34.69) 0.79+-	20.66s (19.88, 21.48) 0.60+-	3.26s (3.12, 3.39) 0.12+-	16.04ms (15.50, 16.44) 0.29+-	6.11ms (5.91, 6.53) 0.20+-
evaluation	-0.11%, -0.04s invariant (-0.04d, 0.94p, 0.87std)	-1.69%, -0.34s invariant (-0.71d, 0.21p, 0.46std)	-5.41%, -0.17s faster✅ (-1.78d, 0.01p, 0.09std)	-1.34%, -0.21ms invariant (-0.89d, 0.13p, 0.23std)	+0.50%, 0.03ms invariant (0.17d, 0.76p, 0.18std)
WGLMakie	–	–	–	–	–
master	–	–	–	–	–
evaluation	–	–	–	–	–