Links open in the system browser via a platform service (#14) (#20)

ctx.open_url is unreliable on native (notably Windows), so the Help menu,
the Discord buttons, and the start-page links did nothing. Added an open_url
Service hook wired to the `open` crate on native (ShellExecute on Windows);
links::open prefers it and falls back to ctx.open_url (web). link_row now
routes clicks through it instead of ui.hyperlink_to. Test drives every Help
link id + the open() helper through a mock service.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Cargo.lock

@@ -3241,6 +3241,7 @@ dependencies = [
  "eframe",
  "egui",
  "log",
+ "open",
  "photocraft-codecs",
  "photocraft-color",
  "photocraft-compose",

apps/photocraft/Cargo.toml

@@ -29,6 +29,7 @@ log = { workspace = true }
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 rfd = { workspace = true }
 arboard = "3"
+open = "5"
 
 [build-dependencies]
 # Icon + VERSIONINFO for photocraft.exe; build.rs only uses it when targeting Windows.

apps/photocraft/src/services.rs

@@ -80,6 +80,7 @@ pub fn native() -> Services {
             photocraft_codecs::encode(&img, photocraft_codecs::Format::Png, &EncodeOptions::default()).map_err(|e| e.to_string())
         })),
         inbox: None,
+        open_url: Some(Box::new(|url: &str| open::that(url).map_err(|e| e.to_string()))),
         clipboard_set_image: Some(Box::new(|w: u32, h: u32, px: &[u8]| {
             let mut cb = arboard::Clipboard::new().map_err(|e| e.to_string())?;
             cb.set_image(arboard::ImageData { width: w as usize, height: h as usize, bytes: std::borrow::Cow::Borrowed(px) }).map_err(|e| e.to_string())

crates/ui-egui/src/canvas.rs

@@ -597,7 +597,7 @@ fn start_screen(app: &mut PhotocraftApp, ui: &mut egui::Ui) {
             ui.add_space(26.0);
             crate::links::discord_button(app, ui, 190.0);
             ui.add_space(10.0);
-            crate::links::link_row(ui);
+            crate::links::link_row(app, ui);
         });
     });
 }

crates/ui-egui/src/dialogs.rs

@@ -46,7 +46,7 @@ pub fn show(app: &mut PhotocraftApp, ctx: &egui::Context) {
                     ui.vertical_centered(|ui| {
                         crate::links::discord_button(app, ui, 220.0);
                         ui.add_space(8.0);
-                        crate::links::link_row(ui);
+                        crate::links::link_row(app, ui);
                     });
                     ui.add_space(10.0);
                     ui.weak("egui · wgpu · photocraft-engine");

crates/ui-egui/src/lib.rs

@@ -90,6 +90,8 @@ pub type ExportFn = Box<dyn Fn(&Document, &str, &ExportSettings) -> Result<Vec<u
 pub type PickOpenFn = Box<dyn FnMut() -> Option<(String, Vec<u8>)>>;
 pub type PickSaveFn = Box<dyn FnMut(&str) -> Option<String>>;
 pub type WriteFn = Box<dyn FnMut(&str, &[u8]) -> Result<(), String>>;
+/// Open a URL in the system browser (native) — reliable cross-platform, unlike `ctx.open_url`.
+pub type OpenUrlFn = Box<dyn Fn(&str) -> Result<(), String>>;
 pub type EncodePngFn = Box<dyn Fn(u32, u32, &[u8]) -> Result<Vec<u8>, String>>;
 /// Put an RGBA8 image (width, height, pixels) on the OS clipboard.
 pub type ClipboardSetFn = Box<dyn FnMut(u32, u32, &[u8]) -> Result<(), String>>;
@@ -126,6 +128,8 @@ pub struct Services {
     pub write: Option<WriteFn>,
     /// Encode an RGBA8 image as PNG (used for screenshots and `ui.render`).
     pub encode_png: Option<EncodePngFn>,
+    /// Open a URL in the system browser (native). Falls back to `ctx.open_url` (web) when unset.
+    pub open_url: Option<OpenUrlFn>,
     /// Files delivered asynchronously (web file pickers, drag-and-drop): drained every frame.
     pub inbox: Option<Inbox>,
     /// OS clipboard images: copies go out, screenshots and images from other apps come in.

crates/ui-egui/src/links.rs

@@ -25,9 +25,13 @@ pub fn url_for(id: &str) -> Option<&'static str> {
     COMMANDS.iter().find(|c| c.0 == id).map(|c| c.1)
 }
 
-/// Open `url` in the system browser (a new tab on the web) and note it in the status bar.
+/// Open `url` in the system browser (a new tab on the web) and note it in the status bar. Prefers
+/// the platform `open_url` service (reliable on Windows/macOS/Linux); falls back to `ctx.open_url`.
 pub fn open(app: &mut PhotocraftApp, ctx: &egui::Context, url: &str) -> Value {
-    ctx.open_url(egui::OpenUrl::new_tab(url));
+    let opened = app.services.open_url.as_ref().map(|f| f(url).is_ok()).unwrap_or(false);
+    if !opened {
+        ctx.open_url(egui::OpenUrl::new_tab(url));
+    }
     app.ui.status = format!("Opened {url}");
     json!({"url": url})
 }
@@ -41,14 +45,16 @@ pub fn discord_button(app: &mut PhotocraftApp, ui: &mut egui::Ui, min_width: f32
     r
 }
 
-/// "PhotoCraft website · GitHub · ArtCraft" as hyperlinks, centred in the available width.
-pub fn link_row(ui: &mut egui::Ui) {
+/// "PhotoCraft website · GitHub · ArtCraft" as links, centred. Clicks route through [`open`] (the
+/// platform browser service) rather than `ui.hyperlink_to`, which uses the unreliable `ctx.open_url`.
+pub fn link_row(app: &mut PhotocraftApp, ui: &mut egui::Ui) {
     let t = crate::theme::Tokens::get(ui.ctx());
     let links = [("PhotoCraft website", APP_PAGE), ("GitHub", GITHUB), ("ArtCraft", ARTCRAFT_WEBSITE)];
     let font = egui::FontId::proportional(12.5);
     let sep = "  ·  ";
     let width: f32 = links.iter().map(|(l, _)| ui.painter().layout_no_wrap((*l).into(), font.clone(), t.text).size().x).sum::<f32>()
         + 2.0 * ui.painter().layout_no_wrap(sep.into(), font.clone(), t.text).size().x;
+    let mut clicked: Option<&str> = None;
     ui.horizontal(|ui| {
         ui.spacing_mut().item_spacing.x = 0.0;
         ui.add_space(((ui.available_width() - width) / 2.0).max(0.0));
@@ -56,15 +62,46 @@ pub fn link_row(ui: &mut egui::Ui) {
             if i > 0 {
                 ui.label(egui::RichText::new(sep).font(font.clone()).color(t.text_faint));
             }
-            ui.hyperlink_to(egui::RichText::new(*label).font(font.clone()), *url).on_hover_text(*url);
+            if ui.link(egui::RichText::new(*label).font(font.clone()).color(t.accent)).on_hover_text(*url).clicked() {
+                clicked = Some(url);
+            }
         }
     });
+    if let Some(url) = clicked {
+        open(app, ui.ctx(), url);
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    #[test]
+    fn links_open_through_the_platform_service() {
+        // Issue #14: links (Help menu, Discord button, start-page links) must open in the browser.
+        // They route through the `open_url` service rather than the unreliable `ctx.open_url`.
+        use std::sync::{Arc, Mutex};
+        let opened: Arc<Mutex<Vec<String>>> = Arc::new(Mutex::new(Vec::new()));
+        let rec = opened.clone();
+        let services = crate::Services {
+            open_url: Some(Box::new(move |u: &str| {
+                rec.lock().unwrap().push(u.to_string());
+                Ok(())
+            })),
+            ..Default::default()
+        };
+        let mut app = PhotocraftApp::new(photocraft_engine::Session::new(), services);
+        let ctx = egui::Context::default();
+        // Every Help-menu link id reaches the service with its URL.
+        for (id, url) in COMMANDS {
+            crate::menus::invoke(&mut app, &ctx, id, json!({})).unwrap();
+            assert_eq!(opened.lock().unwrap().last().map(String::as_str), Some(*url), "{id}");
+        }
+        // The direct open() helper (Discord button / start-page links) also uses it.
+        open(&mut app, &ctx, DISCORD);
+        assert_eq!(opened.lock().unwrap().last().map(String::as_str), Some(DISCORD));
+    }
+
     #[test]
     fn help_menu_lists_links_then_separator_then_about() {
         let app = PhotocraftApp::new(photocraft_engine::Session::new(), Default::default());