replace PLOTS_DEFAULT_BACKEND by Preferences

Project.toml

@@ -1,7 +1,7 @@
 name = "Plots"
 uuid = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
 author = ["Tom Breloff (@tbreloff)"]
-version = "1.36.4"
+version = "1.36.5"
 
 [deps]
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
@@ -21,6 +21,7 @@ NaNMath = "77ba4419-2d1f-58cd-9bb1-8ffee604a2e3"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 PlotThemes = "ccf2f8ad-2431-5c83-bf29-c5338b663b6a"
 PlotUtils = "995b91a9-d308-5afd-9ec6-746e21dbc043"
+Preferences = "21216c6a-2e73-6563-6e65-726566657250"
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 REPL = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
@@ -62,6 +63,7 @@ PyCall = "1"
 PyPlot = "2"
 RecipesBase = "1.3.1"
 RecipesPipeline = "0.6.10"
+Preferences = "1"
 Reexport = "0.2, 1"
 RelocatableFolders = "0.3, 1"
 Requires = "1"

src/Plots.jl

@@ -35,6 +35,7 @@ using Base.Meta
 using Requires
 using Reexport
 using Unzip
+@reexport using Preferences
 @reexport using RecipesBase
 @reexport using PlotThemes
 @reexport using PlotUtils
@@ -204,9 +205,11 @@ include("init.jl")
 
 include("backends/plotly.jl")
 include("backends/web.jl")
-include("backends/gr.jl")
 
 include("shorthands.jl")
-include("precompile.jl")
+@static if backend(_pick_default_backend()) == GRBackend()
+    include("backends/gr.jl")
+    include("precompile.jl")
+end
 
 end

src/backends.jl

@@ -36,8 +36,6 @@ macro init_backend(s)
     end |> esc
 end
 
-# include("backends/web.jl")
-
 # ---------------------------------------------------------
 
 # don't do anything as a default
@@ -131,20 +129,19 @@ CurrentBackend(sym::Symbol) = CurrentBackend(sym, _backend_instance(sym))
 
 # ---------------------------------------------------------
 
-_fallback_default_backend() = backend(GRBackend())
+_fallback_default_backend() = "gr"
+function _default_backend()
+    Symbol(lowercase(@load_preference("default_backend", _fallback_default_backend())))
+end
 
 function _pick_default_backend()
-    if (env_default = get(ENV, "PLOTS_DEFAULT_BACKEND", "")) != ""
-        if (sym = Symbol(lowercase(env_default))) in _backends
-            backend(sym)
-        else
-            @warn """You have set PLOTS_DEFAULT_BACKEND=$env_default, but it is not a valid backend package.
-            Choose from: \n\t$(join(sort(_backends), "\n\t"))
-            """
-            _fallback_default_backend()
-        end
+    if (sym = _default_backend()) in _backends
+        backend(sym)
     else
-        _fallback_default_backend()
+        @warn """You have set $sym as the default backend, but it is not a valid backend package.
+        Choose from: \n\t$(join(sort(_backends), "\n\t"))
+        """
+        backend(_fallback_default_backend())
     end
 end
 
@@ -289,7 +286,7 @@ end
 # ------------------------------------------------------------------------------
 # gr
 
-_initialize_backend(pkg::GRBackend) = nothing  # COV_EXCL_LINE
+_initialize_backend(pkg::GRBackend) = @eval Plots import GR  # COV_EXCL_LINE
 
 const _gr_attr = merge_with_base_supported([
     :annotations,

src/backends/gr.jl

@@ -1231,8 +1231,8 @@ function gr_get_legend_geometry(vp, sp)
     span_hspace = span + pad  # part of the horizontal increment
     dx = (textw + (vertical ? 0 : span_hspace)) * get(ekw, :legend_wfactor, 1)
 
-    # This is to prevent that linestyle is obscured by large markers. 
-    # We are trying to get markers to not be larger than half the line length. 
+    # This is to prevent that linestyle is obscured by large markers.
+    # We are trying to get markers to not be larger than half the line length.
     # 1 / leg.dy translates base_factor to line length units (important in the context of size kwarg)
     # gr_legend_marker_to_line_factor is an empirical constant to translate between line length unit and marker size unit
     base_markersize = gr_legend_marker_to_line_factor[] * span / dy  # NOTE: arbitrarily based on horizontal measures !

src/init.jl

@@ -3,6 +3,7 @@ using Scratch
 using REPL
 
 const plotly_local_file_path = Ref{Union{Nothing,String}}(nothing)
+const BACKEND_PATH_GR = @path joinpath(@__DIR__, "backends", "gr.jl")
 const BACKEND_PATH_GASTON = @path joinpath(@__DIR__, "backends", "gaston.jl")
 const BACKEND_PATH_HDF5 = @path joinpath(@__DIR__, "backends", "hdf5.jl")
 const BACKEND_PATH_INSPECTDR = @path joinpath(@__DIR__, "backends", "inspectdr.jl")
@@ -63,6 +64,11 @@ function __init__()
             )
         end,
     )
+    if _default_backend() !== :gr
+        @require GR = "28b8d3ca-fb5f-59d9-8090-bfdbd6d07a71" begin
+            include(BACKEND_PATH_GR)
+        end
+    end
 
     @require HDF5 = "f67ccb44-e63f-5c2f-98bd-6dc0ccc4ba2f" begin
         include(BACKEND_PATH_HDF5)

test/runtests.jl

@@ -30,6 +30,7 @@ hdf5()
 gr()
 
 for name in (
+    "init",
     "quality",
     "misc",
     "utils",

test/test_init.jl

@@ -0,0 +1,23 @@
+using Plots, Test
+
+const plots_path = escape_string(pkgdir(Plots))
+
+@testset "Default Backend" begin
+    set_preferences!(Plots, "default_backend" => "plotly")
+    out = run(```
+           $(Base.julia_cmd()) -E """
+               using Pkg
+               Pkg.activate(; temp = true)
+               Pkg.develop(path = \"$(plots_path)\")
+               using Test
+               using Plots
+               @test backend() == Plots.PlotlyBackend()
+               """
+           ```)
+    @test out.exitcode == 0
+    set_preferences!(
+        Plots,
+        "default_backend" => Plots._fallback_default_backend(),
+        force = true,
+    )
+end