fonts: extra font folders from EFFECTCRAFT_FONT_DIRS

A tool can hand EffectCraft its own font library (a path list) without
installing the fonts system-wide; the folders are scanned like the
system ones.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/text/src/fonts.rs

@@ -94,10 +94,17 @@ impl DirectorySource {
                 dirs.push(h.join(".fonts"));
             }
         }
+        dirs.extend(extra_dirs(std::env::var_os("EFFECTCRAFT_FONT_DIRS").as_deref()));
         Self { dirs }
     }
 }
 
+/// Extra font folders from `EFFECTCRAFT_FONT_DIRS` (a path list, `:`-separated, `;` on Windows), so a
+/// tool can hand EffectCraft its own font library without installing the fonts system-wide.
+fn extra_dirs(var: Option<&std::ffi::OsStr>) -> Vec<PathBuf> {
+    var.map(|v| std::env::split_paths(v).filter(|p| !p.as_os_str().is_empty()).collect()).unwrap_or_default()
+}
+
 fn walk(dir: &std::path::Path, depth: u32, out: &mut Vec<PathBuf>) {
     let Ok(rd) = std::fs::read_dir(dir) else { return };
     for e in rd.flatten() {
@@ -824,6 +831,14 @@ fn system_fallback(c: char, style: &str) -> Option<FaceId> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn extra_font_dirs_come_from_a_path_list() {
+        assert!(extra_dirs(None).is_empty());
+        let v = std::env::join_paths(["/a/fonts", "/b/more"]).unwrap_or_default();
+        assert_eq!(extra_dirs(Some(&v)), vec![PathBuf::from("/a/fonts"), PathBuf::from("/b/more")]);
+        assert!(extra_dirs(Some(std::ffi::OsStr::new(""))).is_empty());
+    }
+
     #[test]
     fn bundled_families_and_resolution() {
         let fams = families();

docs/agents.md

@@ -495,6 +495,8 @@ styles, origin (`bundled`, `system`, `user`) and own-language name (`{"query":"g
 by name; `{"rescan":true}` first picks up fonts installed since launch). Pass a listed `family` and
 one of its `styles` to `layer.setText {"font", "style"}`; `text.fontFeatures` says which OpenType
 options a font draws with its own glyphs.
+A tool with its own font library can hand it over without installing it: folders listed in
+`EFFECTCRAFT_FONT_DIRS` (a path list, `:`-separated, `;` on Windows) are scanned like the system font folders.
 
 In expressions, `text.sourceText.style` / `getStyleAt(i, t)` read styles and the setters
 (`setFontSize(v, start?, count?)`, `setFillColor`, `setText`, `setJustification`…) return a