Cmd/Ctrl+= and - zoom the canvas only, not the whole interface (fixes #580)

crates/ui-egui/src/lib.rs

@@ -902,6 +902,9 @@ impl FigApp {
             self.language = Some(self.session.prefs.language.clone());
         }
         if !self.fonts_installed {
+            // Cmd/Ctrl+= / - / 0 zoom the canvas (view.zoomIn, view.zoomOut, view.zoom100): egui's
+            // own keyboard zoom would scale the whole interface on the same keys.
+            ctx.options_mut(|o| o.zoom_with_keyboard = false);
             theme::install_fonts(ctx, false, 0);
             self.fonts_installed = true;
         } else if figcraft_text::system_fonts_scanned() {

crates/ui-egui/src/shortcut_keys_tests.rs

@@ -2,7 +2,8 @@
 //! headless: arrows pan with nothing selected, the keyboard box selection key and Cmd/Ctrl+arrows
 //! drawing it out, list indentation while editing text, symbols another keyboard layout types with
 //! Shift, the presentation keys (Space and N forward, C comments, F full screen), Alt+R for the
-//! rotation origin and Enter placing a shape with its tool chosen.
+//! rotation origin, Enter placing a shape with its tool chosen and Cmd/Ctrl+= and - zooming the
+//! canvas, not the interface.
 
 use egui::{Event, Key, Modifiers, ViewportCommand, ViewportId};
 use figcraft_doc::NodeId;
@@ -211,3 +212,19 @@ fn full_screen_key_and_command_toggle_the_window() {
     u.app.run("view.fullscreen", json!({"on": "yes"}));
     u.frame(vec![]);
 }
+
+#[test]
+fn cmd_plus_and_minus_zoom_the_canvas_not_the_interface() {
+    let mut u = Ui::new(Session::new());
+    u.app.run("view.set", json!({"zoom": 1.0, "cx": 0, "cy": 0}));
+    press(&mut u, Key::Equals, cmd());
+    // egui applies a new zoom factor at the start of the next frame.
+    u.frame(vec![]);
+    assert!(view(&u).2 > 1.0, "Cmd/Ctrl+= zooms the canvas in: {}", view(&u).2);
+    assert_eq!(u.ctx.zoom_factor(), 1.0, "and leaves the interface at its size");
+    press(&mut u, Key::Minus, cmd());
+    press(&mut u, Key::Minus, cmd());
+    u.frame(vec![]);
+    assert!(view(&u).2 < 1.0, "Cmd/Ctrl+- zooms the canvas out: {}", view(&u).2);
+    assert_eq!(u.ctx.zoom_factor(), 1.0);
+}