Add configuration for captured mime types.

Fixes fredrikekre#182.

src/Literate.jl

@@ -260,6 +260,7 @@ 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["mime_extensions"] = [(MIME("image/png"), ".png"), (MIME("image/jpeg"), ".jpeg")]
     # 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 +371,10 @@ 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).
+- `mime_extensions`: A vector of `(mime, ext)` tuples, with the default
+  `[(MIME("image/png"), ".png"), (MIME("image/jpeg"), ".jpeg")]`. 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 +528,9 @@ 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"],
+                                  mime_extensions=config["mime_extensions"])
             end
         end
         write(iomd, '\n') # add a newline between each chunk
@@ -538,7 +545,8 @@ 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,
+                           mime_extensions::Vector)
     # TODO: Deal with explicit display(...) calls
     r, str, _ = execute_block(sb, block; inputfile=inputfile)
     # issue #101: consecutive codefenced blocks need newline
@@ -553,7 +561,7 @@ 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 mime_extensions
             if showable(mime, r)
                 file = string(hash(block) % UInt32) * ext
                 open(joinpath(outputdir, file), "w") do io

test/runtests.jl

@@ -840,6 +840,17 @@ end end
             write(f, "1 + 1")
             Literate.markdown(f, outdir)
             @test occursin("file_with_space", read(joinpath(outdir, "file with space.md"), String))
+
+            # fredrikekre/Literate.jl#182
+            write(inputfile, """
+                struct SVG end
+                Base.show(io::IO, mime::MIME"image/svg", ::SVG) = print(io, "SVG")
+                SVG()
+            """)
+            Literate.markdown(inputfile, outdir; execute=true,
+                              config = Dict("mime_extensions" => [(MIME("image/svg"), ".svg")]))
+            markdown = read(joinpath(outdir, "inputfile.md"), String)
+            @test occursin(r"!\[\]\(\d+\.svg\)", markdown) # image/svg
         end
     end
 end end