Support image/svg+xml for markdown execution. (#183)

src/Literate.jl

@@ -224,6 +224,9 @@ end
 filename(str) = first(splitext(last(splitdir(str))))
 isdocumenter(cfg) = cfg["flavor"]::AbstractFlavor isa DocumenterFlavor
 
+_DEFAULT_IMAGE_FORMATS = [(MIME("image/svg+xml"), ".svg"), (MIME("image/png"), ".png"),
+                          (MIME("image/jpeg"), ".jpeg")]
+
 function create_configuration(inputfile; user_config, user_kwargs, type=nothing)
     # Combine user config with user kwargs
     user_config = Dict{String,Any}(string(k) => v for (k, v) in user_config)
@@ -260,6 +263,7 @@ function create_configuration(inputfile; user_config, user_kwargs, type=nothing)
                        !get(user_config, "execute", cfg["execute"]) ?
                        ("````@example $(get(user_config, "name", replace(cfg["name"], r"\s" => "_")))" => "````") :
                        ("````julia" => "````")
+    cfg["image_formats"] = _DEFAULT_IMAGE_FORMATS
     # Guess the package (or repository) root url
     edit_commit = "master" # TODO: Make this configurable like Documenter?
     deploy_branch = "gh-pages" # TODO: Make this configurable like Documenter?
@@ -370,6 +374,9 @@ Available options:
 - `repo_root_path`: Filepath to the root of the repository. Determined automatically on
   Travis CI, GitHub Actions and GitLab CI. Used for computing
   [Documenters `EditURL`](@ref Interaction-with-Documenter).
+- `image_formats`: A vector of `(mime, ext)` tuples, with the default
+  `$(_DEFAULT_IMAGE_FORMATS)`. Results which are `showable` with a MIME type are saved with
+  the first match, with the corresponding extension.
 """
 const DEFAULT_CONFIGURATION=nothing # Dummy const for documentation
 
@@ -523,7 +530,9 @@ function markdown(inputfile, outputdir=pwd(); config::Dict=Dict(), kwargs...)
             write_code && write(iomd, seekstart(iocode))
             if config["execute"]::Bool
                 execute_markdown!(iomd, sb, join(chunk.lines, '\n'), outputdir;
-                                  inputfile=config["literate_inputfile"], flavor=config["flavor"])
+                                  inputfile=config["literate_inputfile"],
+                                  flavor=config["flavor"],
+                                  image_formats=config["image_formats"])
             end
         end
         write(iomd, '\n') # add a newline between each chunk
@@ -538,7 +547,8 @@ function markdown(inputfile, outputdir=pwd(); config::Dict=Dict(), kwargs...)
 end
 
 function execute_markdown!(io::IO, sb::Module, block::String, outputdir;
-                           inputfile::String="<unknown>", flavor::AbstractFlavor)
+                           inputfile::String="<unknown>", flavor::AbstractFlavor,
+                           image_formats::Vector)
     # TODO: Deal with explicit display(...) calls
     r, str, _ = execute_block(sb, block; inputfile=inputfile)
     # issue #101: consecutive codefenced blocks need newline
@@ -553,7 +563,7 @@ function execute_markdown!(io::IO, sb::Module, block::String, outputdir;
             write(io, "\n", htmlfence.second, "\n")
             return
         end
-        for (mime, ext) in [(MIME("image/png"), ".png"), (MIME("image/jpeg"), ".jpeg")]
+        for (mime, ext) in image_formats
             if showable(mime, r)
                 file = string(hash(block) % UInt32) * ext
                 open(joinpath(outputdir, file), "w") do io

test/runtests.jl

@@ -778,6 +778,10 @@ end end
                 Base.show(io::IO, mime::MIME"image/jpeg", ::JPEG) = print(io, "JPEG")
                 JPEG()
                 #-
+                struct SVG end
+                Base.show(io::IO, mime::MIME"image/svg+xml", ::SVG) = print(io, "SVG")
+                SVG()
+                #-
                 struct MD end
                 Base.show(io::IO, mime::MIME"text/markdown", ::MD) = print(io, "# " * "MD")
                 Base.show(io::IO, mime::MIME"text/html", ::MD) =
@@ -805,6 +809,7 @@ end end
             @test occursin("```\n2×2 $(Matrix{Int}):\n 1  2\n 3  4\n```", markdown) # text/plain
             @test occursin(r"!\[\]\(\d+\.png\)", markdown) # image/png
             @test occursin(r"!\[\]\(\d+\.jpeg\)", markdown) # image/jpeg
+            @test occursin(r"!\[\]\(\d+\.svg\)", markdown) # image/svg+xml, fredrikekre/Literate.jl#182
             @test occursin("# MD", markdown) # text/markdown
             @test occursin("```@raw html\n<h1>MD</h1>\n```", markdown) # text/html
             @test occursin("```\nhello, world\n```", markdown) # stdout/stderr