Fix #683: Preferences > Type > Additional Fonts Folder

VectorCraft found fonts only in the system's font folders (and, on Windows,
those font services activate). A new preference names one more folder, read
with its subfolders after the platform's: its fonts are listed in the font
menus and used as if installed, without installing them.

- vectorcraft_text::set_user_font_dirs / user_font_dirs: folders
  system_font_dirs adds to every scan (none on wasm).
- prefs fontsFolder (Type > Options > Additional Fonts Folder), trimmed; when
  it changes after the first scan, the fonts are scanned again at once, so the
  folder's fonts appear (or go) and type in them lays out again.
- The label is translated where Additional Plug-ins Folder is.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/fonts.rs

@@ -247,7 +247,7 @@ fn font_list(_: &mut Session, p: &Value) -> Result<Value> {
     }
 }
 
-fn rescan(s: &mut Session, _: &Value) -> Result<Value> {
+pub(crate) fn rescan(s: &mut Session, _: &Value) -> Result<Value> {
     let db = vectorcraft_text::FontDb::global();
     #[cfg(not(target_arch = "wasm32"))]
     let faces = db.load_system_fonts();
@@ -283,6 +283,21 @@ fn rescan(s: &mut Session, _: &Value) -> Result<Value> {
 mod tests {
     use super::*;
 
+    /// Type › Options › Additional Fonts Folder (#683) adds its folder to the system font scan,
+    /// trimmed; clearing it takes the folder out again.
+    #[test]
+    fn the_additional_fonts_folder_joins_the_font_scan() {
+        let mut s = Session::new();
+        let dir = std::env::temp_dir().join("vectorcraft-fonts-folder-pref");
+        s.execute("prefs.set", &json!({"key": "fontsFolder", "value": format!("  {}  ", dir.display())})).unwrap();
+        assert_eq!(vectorcraft_text::user_font_dirs(), std::slice::from_ref(&dir));
+        if !cfg!(target_arch = "wasm32") {
+            assert!(vectorcraft_text::system_font_dirs().contains(&dir));
+        }
+        s.execute("prefs.set", &json!({"key": "fontsFolder", "value": ""})).unwrap();
+        assert!(vectorcraft_text::user_font_dirs().is_empty() && !vectorcraft_text::system_font_dirs().contains(&dir));
+    }
+
     #[test]
     fn list_flag_missing_replace_and_select() {
         let mut s = Session::new();

crates/engine/src/cmd/prefscmds.rs

@@ -187,6 +187,7 @@ pub const PREF_SPECS: &[PrefSpec] = &[
     p!("missingGlyphProtection", "Type", "Options", "Enable Missing Glyph Protection", bool),
     p!("highlightAlternateGlyphs", "Type", "Options", "Highlight Alternate Glyphs", bool),
     p!("placeholderText", "Type", "Options", "Fill New Type Objects With Placeholder Text", bool),
+    p!("fontsFolder", "Type", "Options", "Additional Fonts Folder", text),
     // Units
     p!("unitsGeneral", "Units", "", "General", choice(UNITS)),
     p!("unitsStroke", "Units", "", "Stroke", choice(UNITS)),
@@ -460,7 +461,18 @@ impl Session {
         let grid_changed = p.gridline_every != self.prefs.gridline_every || p.grid_subdivisions != self.prefs.grid_subdivisions;
         let history_changed = p.history_states != self.prefs.history_states;
         let tile_edge_changed = p.pattern_tile_edge_color != self.prefs.pattern_tile_edge_color;
+        let fonts_folder_changed = p.fonts_folder != self.prefs.fonts_folder;
         self.prefs = p;
+        if fonts_folder_changed {
+            let folder = self.prefs.fonts_folder.trim();
+            vectorcraft_text::set_user_font_dirs(if folder.is_empty() { vec![] } else { vec![folder.into()] });
+            // Once the fonts were scanned, scan again now: the folder's fonts appear (or go) in the
+            // font menus, and type in them lays out again. The first scan reads it anyway.
+            if vectorcraft_text::FontDb::global().installed_fonts_changed() {
+                // Its result only counts the faces cataloged.
+                let _ = super::fonts::rescan(self, &serde_json::Value::Null);
+            }
+        }
         vectorcraft_render::set_default_threads(u16::try_from(self.prefs.render_threads).ok());
         for st in &mut self.docs {
             if history_changed {

crates/engine/src/lib.rs

@@ -480,6 +480,9 @@ pub struct Prefs {
     // Hyphenation
     pub hyphenation_language: String,
     pub hyphenation_exceptions: String,
+    /// Type › Options › Additional Fonts Folder: a folder (read with its subfolders) whose fonts
+    /// are listed and used as if installed (#683); empty for none.
+    pub fonts_folder: String,
     // Performance & Storage (Plug-ins & Scratch Disks)
     pub plugins_folder: String,
     pub scratch_primary: String,
@@ -696,6 +699,7 @@ impl Default for Prefs {
             slice_line_color: s("#ff3f3f"),
             hyphenation_language: s("English: USA"),
             hyphenation_exceptions: String::new(),
+            fonts_folder: String::new(),
             plugins_folder: String::new(),
             scratch_primary: s("Startup"),
             scratch_secondary: s("None"),

crates/text/src/fontdb.rs

@@ -878,6 +878,31 @@ pub fn set_platform_font_files(list: PlatformFontFiles) {
     let _ = list;
 }
 
+/// Folders the user adds to the font scan (Preferences › Type › Additional Fonts Folder, #683),
+/// read with their subfolders after the platform's.
+#[cfg(not(target_arch = "wasm32"))]
+static USER_FONT_DIRS: std::sync::RwLock<Vec<PathBuf>> = std::sync::RwLock::new(Vec::new());
+
+/// Have [`system_font_dirs`] also read `dirs` (#683), so the fonts in them are listed and used as
+/// if installed. The next check for installed fonts ([`FontDb::installed_fonts_changed`]) then
+/// reports the change, and a scan catalogs them.
+pub fn set_user_font_dirs(dirs: Vec<PathBuf>) {
+    #[cfg(not(target_arch = "wasm32"))]
+    {
+        *USER_FONT_DIRS.write().unwrap_or_else(std::sync::PoisonError::into_inner) = dirs;
+    }
+    #[cfg(target_arch = "wasm32")]
+    let _ = dirs;
+}
+
+/// The folders [`set_user_font_dirs`] added (none on wasm).
+pub fn user_font_dirs() -> Vec<PathBuf> {
+    #[cfg(not(target_arch = "wasm32"))]
+    return USER_FONT_DIRS.read().unwrap_or_else(std::sync::PoisonError::into_inner).clone();
+    #[cfg(target_arch = "wasm32")]
+    Vec::new()
+}
+
 /// The platform's font folders (the system's and the user's) and the font files known to it
 /// outside them (on Windows those registered with it, and those [`set_platform_font_files`]
 /// lists), scanned by [`FontDb::global`].
@@ -926,6 +951,7 @@ pub fn system_font_dirs() -> Vec<PathBuf> {
         let files = fonts_outside(list(), &dirs);
         dirs.extend(files);
     }
+    dirs.extend(user_font_dirs());
     dirs
 }
 

crates/text/src/lib.rs

@@ -25,8 +25,8 @@ pub mod thread;
 pub use craft_fonts::{CRAFT_FONTS, CraftFont};
 pub use features::{LIGATURE_TRACKING_LIMITS, OtFeatures, explicit_ligatures, ligatures_suppressed_by};
 pub use fontdb::{
-    FALLBACK_FAMILY, FontClass, FontDb, FontFace, FontMatch, FontTraits, IcfMargins, PlatformFontFiles, set_platform_font_files, style_weight,
-    system_font_dirs,
+    FALLBACK_FAMILY, FontClass, FontDb, FontFace, FontMatch, FontTraits, IcfMargins, PlatformFontFiles, set_platform_font_files, set_user_font_dirs,
+    style_weight, system_font_dirs, user_font_dirs,
 };
 use kurbo::{Affine, BezPath, Point, Rect, Vec2};
 pub use layout::{layout, layout_with};

crates/ui-egui/src/i18n/es.tsv

@@ -76,6 +76,7 @@
 	Add to Swatches	Agregar a muestras
 	Add Used Colors	Agregar colores usados
 	Additional Plug-ins Folder	Carpeta de plugins adicionales
+	Additional Fonts Folder	Carpeta de fuentes adicionales
 	Adjust Adjoining Width Points	Ajustar puntos de anchura contiguos
 	Adjust Color Balance…	Ajustar equilibrio de color…
 	Adjust Colors	Ajustar colores

crates/ui-egui/src/i18n/fr.tsv

@@ -77,6 +77,7 @@
 	Add to Swatches	Ajouter au nuancier
 	Add Used Colors	Ajouter les couleurs utilisées
 	Additional Plug-ins Folder	Dossier de modules externes supplémentaires
+	Additional Fonts Folder	Dossier de polices supplémentaires
 	Adjust Adjoining Width Points	Ajuster les points de largeur adjacents
 	Adjust Color Balance…	Régler la balance des couleurs…
 	Adjust Colors	Régler les couleurs

crates/ui-egui/src/i18n/it.tsv

@@ -76,6 +76,7 @@
 	Add to Swatches	Aggiungi ai campioni
 	Add Used Colors	Aggiungi colori usati
 	Additional Plug-ins Folder	Cartella plug-in aggiuntivi
+	Additional Fonts Folder	Cartella font aggiuntivi
 	Adjust Adjoining Width Points	Regola punti di larghezza adiacenti
 	Adjust Color Balance…	Regola bilanciamento colore…
 	Adjust Colors	Regola colori

crates/ui-egui/src/i18n/ja.tsv

@@ -724,6 +724,7 @@
 	Add to Selection	選択範囲に追加
 	Add to Swatches	スウォッチに追加
 	Additional Plug-ins Folder	追加プラグインフォルダー
+	Additional Fonts Folder	追加フォントフォルダー
 	Adjust Adjoining Width Points	隣接する幅ポイントを調整
 	Adjust Colors	カラーを調整
 	Adjust Options:	調整オプション:

crates/ui-egui/src/i18n/pt-br.tsv

@@ -138,6 +138,7 @@
 	Add to Selection	Adicionar à Seleção
 	Add to Swatches	Adicionar às Amostras
 	Additional Plug-ins Folder	Pasta Adicional de Plug-ins
+	Additional Fonts Folder	Pasta Adicional de Fontes
 	Adjust Adjoining Width Points	Ajustar Pontos de Largura Adjacentes
 	Adjust Color Balance…	Ajustar Equilíbrio de Cores…
 	Adjust Colors	Ajustar Cores

crates/ui-egui/src/i18n/ru.tsv

@@ -74,6 +74,7 @@
 	Add to Swatches	Добавить в образцы
 	Add Used Colors	Добавить использованные цвета
 	Additional Plug-ins Folder	Папка дополнительных модулей
+	Additional Fonts Folder	Папка дополнительных шрифтов
 	Adjust Adjoining Width Points	Настроить смежные точки ширины
 	Adjust Color Balance…	Настроить цветовой баланс…
 	Adjust Colors	Настроить цвета

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -79,6 +79,7 @@
 	Add to Swatches	添加到色板
 	Add Used Colors	添加已用颜色
 	Additional Plug-ins Folder	附加增效工具文件夹
+	Additional Fonts Folder	附加字体文件夹
 	Adjust Adjoining Width Points	调整相邻宽度点
 	Adjust Color Balance…	调整色彩平衡…
 	Adjust Colors	调整颜色

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -87,6 +87,7 @@
 	Add to Swatches	新增至色票
 	Add Used Colors	新增使用中的顏色
 	Additional Plug-ins Folder	額外的增效模組資料夾
+	Additional Fonts Folder	額外的字體資料夾
 	Adjust Adjoining Width Points	調整相鄰寬度點
 	Adjust Color Balance…	調整色彩平衡…
 	Adjust Colors	調整顏色