Add package extension for Makie (#1494)

* Add package extension for Makie

* Add Makie to the [extras] section to make it work for Julia v1.8

* Fix typo

* Apply suggestions from code review

Co-authored-by: Hendrik Ranocha <ranocha@users.noreply.github.com>

* Update Project.toml

* Move Makie-specific code to package extension file

* Unconditionally export `iplot`, `iplot!`

* fix export list

* Add missing `using`

* Use more stuff from Trixi

* Extend coverage tracking to package extensions

---------

Co-authored-by: Hendrik Ranocha <ranocha@users.noreply.github.com>

Author: sloede

.github/workflows/ci.yml

@@ -121,7 +121,7 @@ jobs:
           TRIXI_TEST: ${{ matrix.trixi_test }}
       - uses: julia-actions/julia-processcoverage@v1
         with:
-          directories: src,examples
+          directories: src,examples,ext
       - uses: codecov/codecov-action@v3
         with:
           file: ./lcov.info

Project.toml

@@ -42,6 +42,12 @@ Triangulate = "f7e6ffb2-c36d-4f8f-a77e-16e897189344"
 TriplotBase = "981d1d27-644d-49a2-9326-4793e63143c3"
 TriplotRecipes = "808ab39a-a642-4abf-81ff-4cb34ebbffa3"
 
+[weakdeps]
+Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
+
+[extensions]
+TrixiMakieExt = "Makie"
+
 [compat]
 CodeTracking = "1.0.5"
 ConstructionBase = "1.3"
@@ -53,6 +59,7 @@ HDF5 = "0.14, 0.15, 0.16"
 IfElse = "0.1"
 LinearMaps = "2.7, 3.0"
 LoopVectorization = "0.12.118"
+Makie = "0.19"
 MPI = "0.20"
 MuladdMacro = "0.2.2"
 Octavian = "0.3.5"
@@ -78,3 +85,6 @@ Triangulate = "2.0"
 TriplotBase = "0.1"
 TriplotRecipes = "0.1"
 julia = "1.8"
+
+[extras]
+Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"

src/visualization/recipes_makie.jl renamed to ext/TrixiMakieExt.jl

@@ -1,3 +1,26 @@
+# Package extension for adding Makie-based features to Trixi.jl
+module TrixiMakieExt
+
+# Required for visualization code
+# We do not check `isdefined(Base, :get_extension)` since Julia v1.9.0
+# does not load package extensions when their dependency is loaded from
+# the main environment
+if VERSION >= v"1.9.1"
+  using Makie: Makie, GeometryBasics
+else
+  using ..Makie: Makie, GeometryBasics
+end
+
+# Use all exported symbols to avoid having to rewrite `recipes_makie.jl`
+using Trixi
+
+# Use additional symbols that are not exported
+using Trixi: PlotData2DTriangulated, TrixiODESolution, PlotDataSeries, ScalarData, @muladd,
+             wrap_array_native, mesh_equations_solver_cache
+
+# Import functions such that they can be extended with new methods
+import Trixi: iplot, iplot!
+
 # By default, Julia/LLVM does not use fused multiply-add operations (FMAs).
 # Since these FMAs can increase the performance of many numerical algorithms,
 # we need to opt-in explicitly.
@@ -381,3 +404,5 @@ end
 
 
 end # @muladd
+
+end

src/Trixi.jl

@@ -245,7 +245,8 @@ export DGMulti, DGMultiBasis, estimate_dt, DGMultiMesh, GaussSBP
 export ViscousFormulationBassiRebay1, ViscousFormulationLocalDG
 
 # Visualization-related exports
-export PlotData1D, PlotData2D, ScalarPlotData2D, getmesh, adapt_to_mesh_level!, adapt_to_mesh_level
+export PlotData1D, PlotData2D, ScalarPlotData2D, getmesh, adapt_to_mesh_level!, adapt_to_mesh_level,
+       iplot, iplot!
 
 function __init__()
   init_mpi()
@@ -257,10 +258,14 @@ function __init__()
     using .Plots: Plots
   end
 
-  @require Makie="ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a" begin
-    include("visualization/recipes_makie.jl")
-    using .Makie: Makie, GeometryBasics
-    export iplot, iplot! # interactive plot
+  # Until Julia v1.9 is the minimum required version for Trixi.jl, we still support Requires.jl
+  # We do not check `isdefined(Base, :get_extension)` since Julia v1.9.0
+  # does not load package extensions when their dependency is loaded from
+  # the main environment
+  @static if !(VERSION >= v"1.9.1")
+    @require Makie="ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a" begin
+      include("../ext/TrixiMakieExt.jl")
+    end
   end
 
   @require Flux="587475ba-b771-5e3f-ad9e-33799f191a9c" begin

src/visualization/visualization.jl

@@ -8,4 +8,9 @@ include("types.jl")
 include("utilities.jl")
 include("recipes_plots.jl")
 
+# Add function definitions here such that they can be exported from Trixi.jl and extended in the
+# TrixiMakieExt package extension or by the Makie-specific code loaded by Requires.jl
+function iplot end
+function iplot! end
+
 end # @muladd