Use BaseDirs for locating font directories

Identifying the correct platform-specific font directories can be done
mostly correctly most of the time just with a hardcoded list of places
to look (particularly on Apple systems). However, on Windows and
XDG-following (i.e. Linux and friends) systems the user and system font
directories can end up in other places, and accommodating these edge
cases takes some effort.

This effort has already been put in with the BaseDirs package, which is
a small zero-dependency package whose entire purpose is to find the
correct directories for different types of content on various platforms.
So, we can remove the current font-folder-finding code entirely and just
call BaseDirs.fonts() for a reduction in code here and an improvement in
compatibility.

Project.toml

@@ -3,12 +3,14 @@ uuid = "663a7486-cb36-511b-a19d-713bb74d65c9"
 version = "0.10.3"
 
 [deps]
+BaseDirs = "18cc8868-cbac-4acf-b575-c8ff214dc66f"
 ColorVectorSpace = "c3611d14-8923-5661-9e6a-0046d554d3a4"
 Colors = "5ae59095-9a9b-59fe-a467-6f913c188581"
 FreeType = "b38be410-82b0-50bf-ab77-7b57e271db43"
 GeometryBasics = "5c1252a2-5f33-56bf-86c9-59e7332b4326"
 
 [compat]
+BaseDirs = "1"
 ColorVectorSpace = "0.8, 0.9, 0.10"
 Colors = "0.11, 0.12"
 FreeType = "4"

src/FreeTypeAbstraction.jl

@@ -5,6 +5,7 @@ using Base.Iterators: Repeated, repeated
 import Base: /, *, ==, @lock
 import Base.Broadcast: BroadcastStyle, Style, broadcasted
 using GeometryBasics: StaticVector
+using BaseDirs
 
 include("types.jl")
 include("findfonts.jl")
@@ -25,15 +26,24 @@ fontpaths() = valid_fontpaths
 function __init__()
     ft_init()
     atexit(ft_done)
+    append!(valid_fontpaths, BaseDirs.fonts(existent=true))
+    @static if Sys.isunix() && !Sys.isapple()
+        i = firstindex(valid_fontpaths)
+        while i <= length(valid_fontpaths)
+            path = valid_fontpaths[i]
+            if isdir(path)
+                append!(valid_fontpaths, filter(isdir, readdir(path, join=true)))
+            end
+            i += 1
+        end
+    end
     # This method of finding fonts might not work for exotic platforms,
     # so we supply a way to help it with an environment variable.
-    paths = filter(isdir, _font_paths())
     if haskey(ENV, "FREETYPE_ABSTRACTION_FONT_PATH")
         path = ENV["FREETYPE_ABSTRACTION_FONT_PATH"]
         isdir(path) || error("Path in environment variable FREETYPE_ABSTRACTION_FONT_PATH is not a valid directory!")
-        push!(paths, path)
+        push!(valid_fontpaths, path)
     end
-    append!(valid_fontpaths, paths)
 end
 
 if Base.VERSION >= v"1.4.2"

src/findfonts.jl

@@ -1,47 +1,3 @@
-if Sys.isapple()
-    function _font_paths()
-        return [
-            "/Library/Fonts", # Additional fonts that can be used by all users. This is generally where fonts go if they are to be used by other applications.
-            joinpath(homedir(), "Library/Fonts"), # Fonts specific to each user.
-            "/Network/Library/Fonts", # Fonts shared for users on a network
-            "/System/Library/Fonts", # System specific fonts
-            "/System/Library/Fonts/Supplemental", # new location since Catalina
-        ]
-    end
-elseif Sys.iswindows()
-    function _font_paths()
-        return [
-            joinpath(get(ENV, "SYSTEMROOT", "C:\\Windows"), "Fonts"),
-            joinpath(homedir(), "AppData", "Local", "Microsoft", "Windows", "Fonts"),
-        ]
-    end
-else
-    function add_recursive(result, path)
-        for p in readdir(path)
-            pabs = joinpath(path, p)
-            if isdir(pabs)
-                push!(result, pabs)
-                add_recursive(result, pabs)
-            end
-        end
-    end
-    function _font_paths()
-        result = String[]
-        for p in (
-            "/usr/share/fonts",
-            joinpath(homedir(), ".fonts"),
-            joinpath(homedir(), ".local/share/fonts"),
-            "/usr/local/share/fonts"
-        )
-            if isdir(p)
-                push!(result, p)
-                add_recursive(result, p)
-            end
-        end
-        return result
-    end
-end
-
 family_name(x::FTFont) = lowercase(x.family_name)
 style_name(x::FTFont) = lowercase(x.style_name)