Arbitrary coloring functions for streamplot

[asinghvi17]

Description

Allows the user to change the streamplot's coloring function using color = color_func(x::Point)::Number or ::Colorant.

This is a work in progress but I'm putting it up here as a base - will build on it later.

Type of change

Delete options that do not apply:

• New feature (non-breaking change which adds functionality)

Checklist

• Added an entry in NEWS.md (for new features and breaking changes)
• Added or changed relevant sections in the documentation
• Added unit tests for new algorithms, conversion methods, etc.
• Added reference image tests for new plotting functions, recipes, visual options, etc.

[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	13.78s (13.51, 14.11) 0.20+-	1.22s (1.18, 1.25) 0.03+-	864.51ms (839.15, 933.03) 31.55+-	12.21ms (12.01, 12.44) 0.18+-	166.19ms (163.27, 169.16) 2.03+-
master	13.72s (13.50, 13.89) 0.13+-	1.22s (1.20, 1.24) 0.01+-	866.32ms (847.65, 890.10) 17.60+-	12.25ms (12.11, 12.64) 0.20+-	166.17ms (163.13, 171.63) 2.67+-
evaluation	+0.44%, 0.06s invariant (0.35d, 0.52p, 0.17std)	+0.50%, 0.01s invariant (0.29d, 0.59p, 0.02std)	-0.21%, -1.81ms invariant (-0.07d, 0.90p, 24.58std)	-0.30%, -0.04ms invariant (-0.19d, 0.73p, 0.19std)	+0.01%, 0.02ms invariant (0.01d, 0.99p, 2.35std)
CairoMakie	10.33s (10.23, 10.39) 0.05+-	1.07s (1.07, 1.08) 0.00+-	222.35ms (220.80, 223.90) 1.09+-	10.41ms (10.31, 10.51) 0.07+-	6.15ms (6.03, 6.21) 0.06+-
master	10.33s (10.27, 10.37) 0.04+-	1.07s (1.06, 1.07) 0.00+-	211.24ms (210.04, 212.08) 0.74+-	10.56ms (10.47, 10.62) 0.05+-	6.25ms (6.19, 6.32) 0.04+-
evaluation	-0.06%, -0.01s invariant (-0.14d, 0.80p, 0.04std)	+0.63%, 0.01s slower X (1.71d, 0.01p, 0.00std)	+5.00%, 11.11ms slower X (11.89d, 0.00p, 0.92std)	-1.45%, -0.15ms faster ✓ (-2.32d, 0.00p, 0.06std)	-1.58%, -0.1ms faster ✓ (-1.89d, 0.01p, 0.05std)
WGLMakie	13.17s (12.90, 13.35) 0.14+-	1.17s (1.13, 1.21) 0.03+-	11.85s (11.75, 11.97) 0.08+-	14.05ms (13.37, 15.12) 0.54+-	1.22s (1.13, 1.47) 0.11+-
master	13.27s (13.05, 13.47) 0.14+-	1.21s (1.18, 1.24) 0.02+-	11.94s (11.79, 12.21) 0.14+-	13.59ms (13.15, 14.57) 0.50+-	1.16s (1.12, 1.21) 0.03+-
evaluation	-0.71%, -0.09s invariant (-0.66d, 0.24p, 0.14std)	-3.06%, -0.04s faster ✓ (-1.39d, 0.03p, 0.03std)	-0.75%, -0.09s invariant (-0.79d, 0.17p, 0.11std)	+3.28%, 0.46ms invariant (0.88d, 0.13p, 0.52std)	+4.56%, 0.06s invariant (0.66d, 0.26p, 0.07std)

[SimonDanisch]

@asinghvi17 do you still want to fix this PR?

[asinghvi17]

I'm not sure where exactly the issue is but will look into it today or tomorrow. Seems to be a type issue so shouldn't be too hard to correct.

[asinghvi17]

These changes should fix it - it turned out that color was being set according to the palette, so I changed the attribute to color_func.

[lazarusA]

@asinghvi17 this looks ok, it does what is suppose to do. But I don't see any tests, so before merging maybe having would be a good idea. And well, the initial idea was to be able to reproduce the plots from here