From 5c9aaa576ef3adac6ce5879ed6c90139e06f6c42 Mon Sep 17 00:00:00 2001
From: Lucas Garron <code@garron.net>
Date: Sat, 12 Aug 2023 08:31:51 +0900
Subject: [PATCH] Add a missing `potrace` help message.

See: https://github.com/cubing/icons/issues/102
---
 gulpfile.babel.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/gulpfile.babel.js b/gulpfile.babel.js
index 4e3a7d9..71238a4 100644
--- a/gulpfile.babel.js
+++ b/gulpfile.babel.js
@@ -116,12 +116,20 @@ function fontCssPipe() {
 
 function bmp2svg() {
   return through.obj(function(file, enc, next) {
-
     var potraceProcess = child_process.spawn(
       'potrace', ['-o', '-', '-b', 'svg'], {
          stdio: [ 'pipe', 'pipe', 'inherit' ]
        }
     );
+    potraceProcess.on("error", () => {
+      console.error(`
+Could not run \`potrace\`.
+Please ensure that the \`potrace\` binary is available on your \`$PATH\`. For example, install using one of the following:
+
+- apt install potrace (on Linux)
+- brew install potrace (on macOS using Homebrew)
+`)
+    });
 
     potraceProcess.stdin.write(file.contents);
     potraceProcess.stdin.end();