Feature request: Patterned bar plots in CairoMakie

[icweaver]

Following up on the discussion from slack, it would be great if similar functionality to this example in GLMakie from 100daysOfMakie could be brought to CairoMakie as well

using Makie, GLMakie, Random
Random.seed!(3)
# patterns
# `'/'`, `'\\'`, `'-'`, `'|'`, `'x'`, and `'+'`
directions = [Vec2f0(1), Vec2f0(1, -1), Vec2f0(1, 0), Vec2f0(0, 1),
    [Vec2f0(1), Vec2f0(1, -1)], [Vec2f0(1, 0), Vec2f0(0, 1)]]
colors = [:white, :red, (:green, 0.5), :white, (:navy, 0.85),:black]
patterns = [Makie.LinePattern(direction= hatch; width = 5, tilesize=(20,20),
    linecolor = colors[indx], background_color = colors[end-indx+1])
    for (indx, hatch) in enumerate(directions)]
fig = Figure(resolution = (1200,800), fontsize = 32)
ax = Axis(fig[1,1])
for (idx, pattern) in enumerate(patterns)
    barplot!(ax, [idx], [idx*(2rand()+1)], color = pattern, strokewidth = 2)
end
ax.xticks = (1:6, ["/", "\\", "-", "|", "x", "+"])
save("strippedPatterns.png", fig)
fig

[Moelf]

I'd like to try implementing this, any pointer to a similar PR?

[greimel]

not sure if relevant, but here's the PR that added this to Plots.jl JuliaPlots/Plots.jl#3107

[Moelf]

don't think so, this is CairoMakie, for the record, I'd like to know at which point I need to add stuff:

julia> using CairoMakie

julia> p = Pattern('/');

julia> save("/tmp/f.png", barplot([1],[2], color=p))
ERROR: CanonicalIndexError: getindex not defined for Makie.LinePattern
Stacktrace:
  [1] error_if_canonical_getindex(::IndexCartesian, ::Makie.LinePattern, ::Int64, ::Int64)
    @ Base ./abstractarray.jl:1255
  [2] getindex
    @ ./abstractarray.jl:1235 [inlined]
  [3] _getindex
    @ ./abstractarray.jl:1281 [inlined]
  [4] getindex
    @ ./abstractarray.jl:1236 [inlined]
  [5] attr_broadcast_getindex(x::Makie.LinePattern, i::Int64)
    @ Makie ~/Documents/github/Makie.jl/src/utilities/utilities.jl:164
  [6] macro expansion
    @ ~/Documents/github/Makie.jl/src/utilities/utilities.jl:199 [inlined]
  [7] broadcast_foreach(::CairoMakie.var"#64#65"{CairoMakie.CairoScreen{Cairo.CairoSurfaceBase{UInt32}}}, ::Vector{GeometryBasics.HyperRectangle{2, Float32}}, ::Makie.LinePattern, ::Symbol, ::Int64)
    @ Makie ~/Documents/github/Makie.jl/src/utilities/utilities.jl:185
  [8] draw_poly(scene::Scene, screen::CairoMakie.CairoScreen{Cairo.CairoSurfaceBase{UInt32}}, poly::Combined{Makie.poly, Tuple{Vector{GeometryBasics.HyperRectangle{2, Float32}}}}, rects::Vector{GeometryBasics.HyperRectangle{2, Float32}})
    @ CairoMakie ~/Documents/github/Makie.jl/CairoMakie/src/overrides.jl:84
  [9] draw_plot(scene::Scene, screen::CairoMakie.CairoScreen{Cairo.CairoSurfaceBase{UInt32}}, poly::Combined{Makie.poly, Tuple{Vector{GeometryBasics.HyperRectangle{2, Float32}}}})
    @ CairoMakie ~/Documents/github/Makie.jl/CairoMakie/src/overrides.jl:13
 [10] draw_plot(scene::Scene, screen::CairoMakie.CairoScreen{Cairo.CairoSurfaceBase{UInt32}}, primitive::Combined{Makie.barplot, Tuple{Vector{Point{2, Float32}}}})
    @ CairoMakie ~/Documents/github/Makie.jl/CairoMakie/src/infrastructure.jl:255
 [11] cairo_draw(screen::CairoMakie.CairoScreen{Cairo.CairoSurfaceBase{UInt32}}, scene::Scene)
    @ CairoMakie ~/Documents/github/Makie.jl/CairoMakie/src/infrastructure.jl:192
 [12] backend_show(x::CairoMakie.CairoBackend, io::IOContext{IOStream}, #unused#::MIME{Symbol("image/png")}, scene::Scene)
    @ CairoMakie ~/Documents/github/Makie.jl/CairoMakie/src/infrastructure.jl:396

[ffreyer]

This should end up in https://github.com/JuliaPlots/Makie.jl/blob/174ef914759b64fdc271a4be26d692b97a5dfa09/CairoMakie/src/primitives.jl#L624 with a LinePattern in color

[Moelf]

right now it doesn't call this function at all, I guess one of the function on the current stack trace needs to be replaced by a specialization?

[Moelf]

too hard right now because first we probably want to solve:
https://github.com/JuliaPlots/Makie.jl/blob/174ef914759b64fdc271a4be26d692b97a5dfa09/CairoMakie/src/utils.jl#L243-L252

[ffreyer]

Ah right, poly has it's own backend code.

I don't know Cairo well enough to know how these patterns should be implemented, but I don't think you need to worry about that branch. I assume you either need to make a new branch that transforms the pattern into an image and uses it as a repeated texture like opengl, or that Cairo has some version of hatching/patterns natively that you could use

[Moelf]

that branch takes a Matrix (image) pattern as color, I thought it would tile the color for the entire surface, but it's not (as the comment says).

If this branch were to work correctly, I can use it to draw the inside of the bar plot? or I guess this is not the correct way to go about it.

---

I also didn't find anything in Cairo.jl, but maybe something like https://stackoverflow.com/questions/28755265/cairo-fill-a-polygon-with-a-hatch-pattern

[Moelf]

https://gist.github.com/Moelf/f68af0015f96f98264194f05c544771d

[asinghvi17]

We could also draw patterns onto a CairoRecordingSurface using Cairo intrinsics (set_line_width, move_to, line_to) and then set those surfaces as the pattern, and simply clip everything which is not within the area by using e.g. cairo_clip with cairo_path_to. That would make the approach somewhat more flexible and probably render at better resolution in small or vector graphics.

If you can get the patterns onto a recording surface I would be more than happy to help with the second part.

[Moelf]

What's the difference between imagesurface and recordingsurface?

[Moelf]

@asinghvi17 I can't find any use of CairoRecordingSurface inside Makie, but I think it's much easier if we use pattern_set_extend(pattern, Cario.EXTEND_REPEAT):
https://gist.github.com/Moelf/e380d20b307901a6947881dc163a6c62

here we're clipping with arc(), I think if we clip it to a poly, it's basically what you wanted?