Added Kludgine::rebuild_font_system

CHANGELOG.md

@@ -38,6 +38,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - A new feature `plotters` enables integration with the excellent
   [plotters][plotters] crate. `Renderer::as_plot_area()` is a new function that
   returns a `plotters::DrawingArea`.
+- `Kludgine::rebuild_font_system()` is a new function that recreates the
+  `cosmic_text::FontSystem`, which has the net effect of clearing font-database
+  related caches.
 
 [plotters]: https://github.com/plotters-rs/plotters
 

src/text.rs

@@ -24,6 +24,20 @@ impl Kludgine {
         &mut self.text.fonts
     }
 
+    /// Rebuilds the font system, invalidating font database caches.
+    ///
+    /// This function can be invoked after loading fonts into the font database
+    /// to ensure that all future text rendering considers the newly loaded
+    /// fonts.
+    pub fn rebuild_font_system(&mut self) {
+        let existing_system = std::mem::replace(
+            &mut self.text.fonts,
+            cosmic_text::FontSystem::new_with_fonts([]),
+        );
+        let (locale, db) = existing_system.into_locale_and_db();
+        self.text.fonts = cosmic_text::FontSystem::new_with_locale_and_db(locale, db);
+    }
+
     pub(crate) fn update_scratch_buffer(&mut self, text: &str, width: Option<Px>) {
         self.text.update_scratch_buffer(text, self.scale, width);
     }