CODEWITHSUNDEEP
matplotlibjulia
Leandro Acquaroli
Leandro Acquaroli

Reputation: 65

julia-lang - using Colors.jl arrays with PyPlot commands

I am trying to assign an RGB tuple generated with distinguishable_colors from Colors.jl to an specific line with pyplot in Julia lang, for instance:

using PyPlot, Colors
RGB_1 = distinguishable_colors(10)[5]
plot(linspace(1,10,10), color=RGB_1)

But it seems the rgb space colors are not suitable for the plot:

ValueError: to_rgba: Invalid rgba arg "<PyCall.jlwrap RGB{U8}(0.0,0.0,0.0)>"
to_rgb: Invalid rgb arg "<PyCall.jlwrap RGB{U8}(0.0,0.0,0.0)>"
cannot convert argument to rgb sequence

Is there anyway to get the tuple (0.0,0.0,0.0) from the Colors.jl generated arrays, instead of the RGB{U8}(0.0,0.0,0.0)? I noticed that 

plot(linspace(1,10,10), color=(0.0,0.0,0.0))

does work. Julia 0.3.2 with matplotlib 1.4.2.

Upvotes: 4

Views: 1106

Answers (1)

HarmonicaMuse
HarmonicaMuse

Reputation: 7893

You can give the color option of the plot function a tuple of 3 UFixed8 (which is an alias for FixedPointNumbers.UFixed{UInt8,8}). Colors.jl has the following functions red, green and blue to get each respective field from an RGB type, each one of UFixed8 type:

julia> VERSION
v"0.4.6"

julia> using PyPlot, Colors

julia> rgb₁ = distinguishable_colors(10)[5]
RGB{U8}(0.843,0.267,0.0)

julia> rgb_sequence(c::RGB) = (red(c), green(c), blue(c))
rgb (generic function with 1 method)

julia> rgb₁_tuple = rgb_sequence(rgb₁)
(UFixed8(0.843),UFixed8(0.267),UFixed8(0.0))

julia> eltype(rgb₁_tuple)
FixedPointNumbers.UFixed{UInt8,8}

julia> plot(linspace(1, 10, 10), color = rgb₁_tuple)
1-element Array{Any,1}:
 PyObject <matplotlib.lines.Line2D object at 0x000000002864E240>

Out:

enter image description here

Tested on v"0.3.12" also. The only difference is that RGB₁ = distinguishable_colors(10)[5] returns a different color (RGB{U8}(0.0,0.522,1.0)) in my case.

Upvotes: 2

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