Implement the generalized Arrays interface (OffsetArrays)

[yakir12]

Makie should be able to plot the generalized Arrays interface to be compatible with e.g. OffsetArrays.

Currently,

using OffsetArrays, GLMakie
xy = OffsetArray(rand(100), -50)
lines(xy)

results in:

ERROR: DimensionMismatch("arrays could not be broadcast to a common size; got a dimension with lengths 100 and 100")
Stacktrace:
  [1] _bcs1(a::Base.OneTo{Int64}, b::OffsetArrays.IdOffsetRange{Int64, Base.OneTo{Int64}})
    @ Base.Broadcast ./broadcast.jl:516
  [2] _bcs
    @ ./broadcast.jl:510 [inlined]
  [3] broadcast_shape
    @ ./broadcast.jl:504 [inlined]
  [4] combine_axes
    @ ./broadcast.jl:499 [inlined]
  [5] instantiate
    @ ./broadcast.jl:281 [inlined]
  [6] materialize
    @ ./broadcast.jl:904 [inlined]
  [7] convert_arguments(P::PointBased, x::UnitRange{Int64}, y::OffsetVector{Float64, Vector{Float64}})
    @ Makie ~/.julia/packages/Makie/NL7Xw/src/conversions.jl:128
  [8] convert_arguments
    @ ~/.julia/packages/Makie/NL7Xw/src/conversions.jl:139 [inlined]
  [9] convert_arguments(T::Type{Lines{Tuple{OffsetVector{Float64, Vector{Float64}}}}}, args::OffsetVector{Float64, Vector{Float64}}; kw::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Makie ~/.julia/packages/Makie/NL7Xw/src/conversions.jl:10
 [10] convert_arguments
    @ ~/.julia/packages/Makie/NL7Xw/src/conversions.jl:8 [inlined]
 [11] plot!(scene::Scene, P::Type{Lines}, attributes::Attributes, args::OffsetVector{Float64, Vector{Float64}}; kw_attributes::Base.Pairs{Symbol, Bool, Tuple{Symbol}, NamedTuple{(:show_axis,), Tuple{Bool}}})
    @ Makie ~/.julia/packages/Makie/NL7Xw/src/interfaces.jl:321
 [12] plot(P::Type{Lines}, args::OffsetVector{Float64, Vector{Float64}}; axis::NamedTuple{(), Tuple{}}, figure::NamedTuple{(), Tuple{}}, kw_attributes::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Makie ~/.julia/packages/Makie/NL7Xw/src/figureplotting.jl:28
 [13] plot
    @ ~/.julia/packages/Makie/NL7Xw/src/figureplotting.jl:18 [inlined]
 [14] #lines#31
    @ ~/.julia/packages/MakieCore/S8PkO/src/recipes.jl:31 [inlined]
 [15] lines(args::OffsetVector{Float64, Vector{Float64}})
    @ MakieCore ~/.julia/packages/MakieCore/S8PkO/src/recipes.jl:31
 [16] top-level scope
    @ REPL[384]:1

To plot this data we need to:

x = keys(xy)
y = values(xy)
lines(x, y)

[SimonDanisch]

I guess this can be fixed by using keys(y) here:
https://github.com/JuliaPlots/Makie.jl/blob/master/src/conversions.jl#L139

[yakir12]

You guessed right!

[goretkin]

[EDIT] That PR is a step toward fixing the example below, but as noted there, does not yet fix heatmap.

Another example

using Makie
using OffsetArrays
fig = Figure()
ax = Axis(fig[1, 1], title = "Demo")
heatmap!(ax, fill(0.0, (-10:10, -10:10)))

gives this on the current release (does not include #1260)

ulia> heatmap!(ax, fill(0.0, (-10:10, -10:10)))
ERROR: TypeError: in typeassert, expected Matrix{Float32}, got a value of type OffsetMatrix{Float32, Matrix{Float32}}
Stacktrace:
  [1] el32convert(x::OffsetMatrix{Float64, Matrix{Float64}})
    @ Makie ~/.julia/packages/Makie/gQOQF/src/conversions.jl:601
  [2] convert_arguments(#unused#::DiscreteSurface, data::OffsetMatrix{Float64, Matrix{Float64}})
    @ Makie ~/.julia/packages/Makie/gQOQF/src/conversions.jl:312
  [3] convert_arguments(T::Type{Heatmap{Tuple{OffsetMatrix{Float64, Matrix{Float64}}}}}, args::OffsetMatrix{Float64, Matrix{Float64}}; kw::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Makie ~/.julia/packages/Makie/gQOQF/src/conversions.jl:10
  [4] convert_arguments
    @ ~/.julia/packages/Makie/gQOQF/src/conversions.jl:8 [inlined]
  [5] plot!(scene::Scene, P::Type{Heatmap{ArgType} where ArgType}, attributes::Attributes, args::OffsetMatrix{Float64, Matrix{Float64}}; kw_attributes::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Makie ~/.julia/packages/Makie/gQOQF/src/interfaces.jl:321
  [6] plot!(scene::Scene, P::Type{Heatmap{ArgType} where ArgType}, attributes::Attributes, args::OffsetMatrix{Float64, Matrix{Float64}})
    @ Makie ~/.julia/packages/Makie/gQOQF/src/interfaces.jl:308
  [7] plot!(la::Axis, P::Type{Heatmap{ArgType} where ArgType}, attributes::Attributes, args::OffsetMatrix{Float64, Matrix{Float64}}; kw_attributes::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Makie.MakieLayout ~/.julia/packages/Makie/gQOQF/src/makielayout/layoutables/axis.jl:658
  [8] plot!
    @ ~/.julia/packages/Makie/gQOQF/src/makielayout/layoutables/axis.jl:653 [inlined]
  [9] plot!(P::Type{Heatmap{ArgType} where ArgType}, ax::Axis, args::OffsetMatrix{Float64, Matrix{Float64}}; kw_attributes::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Makie.MakieLayout ~/.julia/packages/Makie/gQOQF/src/makielayout/layoutables/axis.jl:670
 [10] plot!(P::Type{Heatmap{ArgType} where ArgType}, ax::Axis, args::OffsetMatrix{Float64, Matrix{Float64}})
    @ Makie.MakieLayout ~/.julia/packages/Makie/gQOQF/src/makielayout/layoutables/axis.jl:669
 [11] heatmap!(::Axis, ::Vararg{Any, N} where N; attributes::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ MakieCore ~/.julia/packages/MakieCore/S8PkO/src/recipes.jl:35
 [12] heatmap!(::Axis, ::Vararg{Any, N} where N)
    @ MakieCore ~/.julia/packages/MakieCore/S8PkO/src/recipes.jl:35
 [13] top-level scope
    @ REPL[28]:1

[ffreyer]

Is this a regression at this point?

[asinghvi17]

I guess it's not a regression so much as it never worked correctly in the first place. I have a PR up for that but should restart discussion at some point.

[asinghvi17]

The heatmap example fails on master because numbers_to_colors can't handle offset arrays in its return type. We should force a regular array in numbers_to_colors.

 fig
Error showing value of type Figure:
ERROR: MethodError: Cannot `convert` an object of type
  OffsetMatrix{ColorTypes.RGBA{Float32}, Matrix{ColorTypes.RGBA{Float32}}} to an object of type
  Union{ColorTypes.RGBA{Float32}, Matrix{ColorTypes.RGBA{Float32}}}

Closest candidates are:
  convert(::Type{T}, ::T) where T
   @ Base Base.jl:84

Stacktrace:
  [1] numbers_to_colors(numbers::OffsetMatrix{…}, colormap::Vector{…}, colorscale::Function, colorrange::Vec{…}, lowclip::ColorTypes.RGBA{…}, highclip::ColorTypes.RGBA{…}, nan_color::ColorTypes.RGBA{…})
    @ Makie ~/.julia/dev/Makie/src/colorsampler.jl:163
  [2] to_color(c::Makie.ColorMapping{2, OffsetMatrix{Float32, Matrix{Float32}}, OffsetMatrix{Float32, Matrix{Float32}}})
    @ Makie ~/.julia/dev/Makie/src/colorsampler.jl:346
  [3] draw_atomic(scene::Scene, screen::CairoMakie.Screen{CairoMakie.IMAGE}, primitive::Union{Image, Heatmap})
    @ CairoMakie ~/.julia/dev/Makie/CairoMakie/src/primitives.jl:805