options: fonts and plot styles can live in a chosen folder

Options > Files lets the fonts and plot style folders move elsewhere,
such as a share a whole team uses (Change... / Default). Fonts are then
looked up and downloaded there, and plot style tables listed and saved
there; the choice is kept in the profile.

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

src/app/mod.rs

@@ -2694,6 +2694,11 @@ pub enum Message {
     SelectionCyclingChanged(bool),
     /// Reveal one of the application's own folders in the system file manager.
     OpenFolder(String),
+    /// Choose another folder for fonts or plot styles (`None` result:
+    /// cancelled).
+    ChooseFolder(crate::ui::window::options::MovableFolder),
+    /// Use this folder, or the default one for `None`.
+    FolderChosen(crate::ui::window::options::MovableFolder, Option<std::path::PathBuf>),
     /// Change isolines per surface in the current drawing (ISOLINES).
     IsolinesChanged(i16),
     /// The isolines slider was released; rebuild the meshes if it moved.

src/app/settings.rs

@@ -443,6 +443,9 @@ pub struct UserSettings {
     pub file_dia: bool,
     /// TRIMEXTENDMODE: TRIM and EXTEND start in Quick mode (else Standard).
     pub trim_extend_quick: bool,
+    /// Fonts and plot styles kept in a chosen folder (`None`: the default).
+    pub fonts_folder: Option<String>,
+    pub plot_styles_folder: Option<String>,
     /// The file type ATTACH's picker was last left on (1-based).
     pub attach_filter: u32,
     /// SURFACEASSOCIATIVITY: new surfaces stay associative to their sources.
@@ -918,6 +921,8 @@ impl Default for UserSettings {
             xref_fade: 50,
             file_dia: true,
             trim_extend_quick: true,
+            fonts_folder: None,
+            plot_styles_folder: None,
             attach_filter: 7,
             surface_associativity: true,
             ucs_ortho: true,

src/app/update/file.rs

@@ -811,6 +811,15 @@ impl OpenCADStudio {
             xref_fade: crate::scene::cache::block_cache::xref_fade_ctl(),
             file_dia: crate::sys::file_dia(),
             trim_extend_quick: crate::modules::draw::modify::trim::quick_mode(),
+            #[cfg(not(target_arch = "wasm32"))]
+            fonts_folder: crate::io::font_repo::fonts_folder().map(|p| p.display().to_string()),
+            #[cfg(not(target_arch = "wasm32"))]
+            plot_styles_folder: crate::io::plot_style::plot_styles_folder()
+                .map(|p| p.display().to_string()),
+            #[cfg(target_arch = "wasm32")]
+            fonts_folder: None,
+            #[cfg(target_arch = "wasm32")]
+            plot_styles_folder: None,
             attach_filter: crate::sys::attach_filter(),
             surface_associativity: crate::scene::model::sweep_model::surface_associativity(),
             ucs_ortho: crate::modules::view::view_cmd::ucs_ortho(),
@@ -948,6 +957,13 @@ impl OpenCADStudio {
         self.ribbon.xref_fade = crate::scene::cache::block_cache::xref_fade_ctl();
         crate::sys::set_file_dia(s.file_dia);
         crate::modules::draw::modify::trim::set_quick_mode(s.trim_extend_quick);
+        #[cfg(not(target_arch = "wasm32"))]
+        {
+            crate::io::font_repo::set_fonts_folder(s.fonts_folder.as_ref().map(Into::into));
+            crate::io::plot_style::set_plot_styles_folder(
+                s.plot_styles_folder.as_ref().map(Into::into),
+            );
+        }
         crate::sys::set_attach_filter(s.attach_filter);
         crate::scene::model::sweep_model::set_surface_associativity(s.surface_associativity);
         crate::modules::view::view_cmd::set_ucs_ortho(s.ucs_ortho);

src/app/update/mod.rs

@@ -9369,6 +9369,34 @@ impl OpenCADStudio {
                 crate::sys::open_url(&path, None)
             }
 
+            #[cfg(target_arch = "wasm32")]
+            Message::ChooseFolder(_) | Message::FolderChosen(..) => Task::none(),
+            #[cfg(not(target_arch = "wasm32"))]
+            Message::ChooseFolder(folder) => Task::perform(
+                async {
+                    rfd::AsyncFileDialog::new()
+                        .pick_folder()
+                        .await
+                        .map(|handle| crate::sys::handle_path(&handle))
+                },
+                move |picked| match picked {
+                    Some(path) => Message::FolderChosen(folder, Some(path)),
+                    None => Message::Noop,
+                },
+            ),
+            #[cfg(not(target_arch = "wasm32"))]
+            Message::FolderChosen(folder, path) => {
+                use crate::ui::window::options::MovableFolder;
+                match folder {
+                    MovableFolder::Fonts => crate::io::font_repo::set_fonts_folder(path),
+                    MovableFolder::PlotStyles => {
+                        crate::io::plot_style::set_plot_styles_folder(path)
+                    }
+                }
+                self.save_config();
+                Task::none()
+            }
+
             Message::PickDragRectToggled(rectangle) => {
                 self.pick_drag_rect = rectangle;
                 self.persist_settings_if_changed();

src/app/view/modal.rs

@@ -375,6 +375,9 @@ impl OpenCADStudio {
                                         .map(|p| p.display().to_string()),
                                     color_books: crate::ui::color_select::book::folder()
                                         .map(|p| p.display().to_string()),
+                                    fonts_moved: crate::io::font_repo::fonts_folder().is_some(),
+                                    plot_styles_moved: crate::io::plot_style::plot_styles_folder()
+                                        .is_some(),
                                 }
                             }
                             #[cfg(target_arch = "wasm32")]