Fixing the use of Ghostscript gs command

.gitignore

@@ -8,3 +8,4 @@
 /docs/site/
 /docs/Manifest.toml
 test/test_images
+examples/out

examples/README.md

@@ -0,0 +1,13 @@
+# Examples
+
+To run those examples, clone the project, resolve Julia dependencies and run from the root of this directory:
+
+Example 1:
+```
+julia examples/readme_example_2.jl
+```
+
+Example 2:
+```
+julia examples/readme_example_2.jl
+```

examples/readme_example_1.jl

@@ -0,0 +1,39 @@
+using Makie
+include("../src/MakieTeX.jl")
+using .MakieTeX
+using CairoMakie # or whichever other backend
+
+# Get Ghostscript path from the environment variable
+ghostscript_path = get(ENV, "GHOSTSCRIPT_PATH", "/usr/bin/gs")  # Fallback to a default path if not set
+
+# Set MakieTeX to use the custom Ghostscript path
+MakieTeX.Ghostscript_jll.gs() = ghostscript_path
+
+# Print to confirm the overridden path
+println("Using Ghostscript at: ", MakieTeX.Ghostscript_jll.gs())
+
+fig = Figure()
+l1 = LTeX(
+    fig[1, 1], L"A \emph{convex} function $f \in C$ is \textcolor{blue}{denoted} as \tikz{\draw[line width=1pt, >->] (0, -2pt) arc (-180:0:8pt);}";
+    tellwidth = false, tellheight = true
+)
+ax1 = Axis(
+    fig[2, 1];
+)
+heatmap!(ax1, Makie.peaks())
+
+display(fig)
+
+# Save the figure to a file in the current directory
+output_dir = "examples/out"
+output_filename = "output_image_1.png"
+img_output_path = joinpath(output_dir, output_filename)
+
+# Check if the directory exists, else create it
+if !isdir(output_dir)
+    println("Directory $output_dir does not exist. Creating it...")
+    mkdir(output_dir)
+end
+
+println("Saving the figure to $img_output_path")
+save(img_output_path, fig)

examples/readme_example_2.jl

@@ -0,0 +1,37 @@
+using Makie
+include("../src/MakieTeX.jl")
+using .MakieTeX
+using CairoMakie # or whichever other backend
+
+println("testing MakieTeX")
+
+# log which tex engine is being used
+println("Using TeX engine: $(MakieTeX.CURRENT_TEX_ENGINE[])")
+
+fig = Figure(size = (400, 300), pt_per_unit = 2);
+tex1 = LTeX(
+    fig[1, 1], 
+    L"\int \mathbf E \cdot d\mathbf a = \frac{Q_{encl}}{4\pi\epsilon_0}", 
+    scale=1,
+    render_density = 2,
+);
+tex2 = LTeX(
+    fig[2, 1], 
+    L"\int \mathbf E \cdot d\mathbf a = \frac{Q_{encl}}{4\pi\epsilon_0}", 
+    scale=2,
+    render_density = 2,
+);
+
+# Save the figure to a file in the current directory
+output_dir = "examples/out"
+output_filename = "output_image_2.png"
+img_output_path = joinpath(output_dir, output_filename)
+
+# Check if the directory exists, else create it
+if !isdir(output_dir)
+    println("Directory $output_dir does not exist. Creating it...")
+    mkdir(output_dir)
+end
+
+println("Saving the figure to $img_output_path")
+save(img_output_path, fig)

flake.nix

@@ -0,0 +1,41 @@
+{
+  description = "Julia environment";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = github:numtide/flake-utils;
+  };
+
+  outputs = { self, nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        # Override the Nix package set to allow unfree packages
+        pkgs = import nixpkgs {
+          system = system; 
+          config.allowUnfree = true; 
+        };
+        # WARN: Nix packaging system doesn't support all packages, so rely on Julia package manager instead.
+        # Use Julia in REPL mode, then package mode and install packages that way.
+        julia = pkgs.julia-bin.overrideDerivation (oldAttrs: { doInstallCheck = false; });
+      in
+      {
+        # development environment
+        devShells.default = pkgs.mkShell {
+          packages = [
+            julia
+            pkgs.ghostscript
+            # LaTeX
+            pkgs.texlive.combined.scheme-full
+          ];
+
+          shellHook = ''
+            export JULIA_NUM_THREADS="auto"
+            export JULIA_PROJECT="."
+            export JULIA_BINDIR=${julia}/bin
+            export JULIA_EDITOR="code"
+            echo "Nix shell loaded."
+          '';
+        };
+      }
+    );
+}

src/MakieTeX.jl

@@ -17,7 +17,7 @@ using DocStringExtensions
 using Poppler_jll, Ghostscript_jll, Glib_jll, tectonic_jll
 using Rsvg, Cairo
 
-# Define some constants for configuration
+# Define some constant references for configuration
 "Render with Poppler pipeline (true) or Cairo pipeline (false)"
 const RENDER_EXTRASAFE = Ref(false)
 "The current `TeX` engine which MakieTeX uses."
@@ -27,6 +27,15 @@ const _PDFCROP_DEFAULT_MARGINS = Ref{Vector{UInt8}}([0,0,0,0])
 "Default density when rendering images"
 const RENDER_DENSITY = Ref(3)
 
+# Runtime checks
+"Boolean that determines whether the command `gs` (Ghostscript) is available in the shell or not."
+const GHOSTSCRIPT_AVAILABLE = if isnothing(Sys.which("gs"))
+    @warn "Failed to find 'gs' in shell path. Defaulting to use Ghostscript_jll. If this fails, please include Ghostscript command `gs` in current shell." 
+    false 
+else 
+    true 
+end
+
 @deprecate TEXT_RENDER_DENSITY RENDER_DENSITY
 
 

src/rendering/pdf_utils.jl

@@ -5,6 +5,18 @@ This file contains a common core for working with PDFs.  It does not contain any
 but functions from here are used in the PDF and TeX rendering pipelines.
 =#
 
+"""
+    ghostscript_gs(command_string::String)
+
+Run a Ghostscript command string.  If the `gs` command is available in the shell, it will be used.  Otherwise, the Ghostscript executable from the `Ghostscript_jll` package will be used.
+"""
+function ghostscript_gs(command_string::Cmd)
+    if GHOSTSCRIPT_AVAILABLE
+        return `gs $command_string`
+    else
+        return `$(Ghostscript_jll.gs()) $command_string`
+    end
+end
 
 """
     pdf_num_pages(filename::String)::Int
@@ -89,11 +101,9 @@ function split_pdf(pdf::Union{Vector{UInt8}, String})
             redirect_stderr(devnull) do
                 redirect_stdout(devnull) do
                     for i in 1:num_pages
-                        Ghostscript_jll.gs() do gs
-                            run(`$gs -q -dBATCH -dNOPAUSE -dFirstPage=$i -dLastPage=$i -sOutputFile=temp_$(lpad(i, 4, '0')).pdf -sDEVICE=pdfwrite temp.pdf`)
-                            push!(pdfs, read("temp_$(lpad(i, 4, '0')).pdf"))
-                            rm("temp_$(lpad(i, 4, '0')).pdf")
-                        end
+                        run(ghostscript_gs(`-q -dBATCH -dNOPAUSE -dFirstPage=$i -dLastPage=$i -sOutputFile=temp_$(lpad(i, 4, '0')).pdf -sDEVICE=pdfwrite temp.pdf`))
+                        push!(pdfs, read("temp_$(lpad(i, 4, '0')).pdf"))
+                        rm("temp_$(lpad(i, 4, '0')).pdf")
                     end
                 end
             end
@@ -114,7 +124,7 @@ function get_pdf_bbox(path::String)
     !isfile(path) && error("File $(path) does not exist!")
     out = Pipe()
     err = Pipe()
-    succ = success(pipeline(`$(Ghostscript_jll.gs()) -q -dBATCH -dNOPAUSE -sDEVICE=bbox $path`, stdout=out, stderr=err))
+    succ = success(pipeline(ghostscript_gs(`-q -dBATCH -dNOPAUSE -sDEVICE=bbox $path`), stdout=out, stderr=err))
 
     close(out.in)
     close(err.in)
@@ -164,9 +174,7 @@ function crop_pdf(path::String; margin = _PDFCROP_DEFAULT_MARGINS[])
     try
         redirect_stderr(err) do
             redirect_stdout(out) do
-                Ghostscript_jll.gs() do gs_exe
-                    run(`$gs_exe -o temp_cropped.pdf -sDEVICE=pdfwrite -c "[/CropBox [$crop_cmd]" -c "/PAGES pdfmark" -f $path`)
-                end
+                run(ghostscript_gs(`-o temp_cropped.pdf -sDEVICE=pdfwrite -c "[/CropBox [$crop_cmd]" -c "/PAGES pdfmark" -f $path`))
             end
         end
     catch e