Restore frozen panes when showing a custom view (#577)

crates/engine/src/cmd/extra.rs

@@ -743,6 +743,17 @@ fn custom_views(s: &mut Session, p: &Json) -> Result<Json> {
         if let Some(z) = v["zoom"].as_u64() {
             s.execute("view.zoom", json!({"percent": z}))?;
         }
+        if let Some(f) = v.get("freeze") {
+            let freeze = match (f[0].as_u64(), f[1].as_u64()) {
+                (Some(r), Some(c)) => u32::try_from(r).ok().zip(u32::try_from(c).ok()),
+                _ => None,
+            };
+            edit(s, |cx| {
+                let si = cx.sheet_index();
+                cx.sheet_mut(si)?.freeze = freeze;
+                Ok(())
+            })?;
+        }
     } else if let Some(name) = str_param(p, "delete") {
         if let Some(o) = views.as_object_mut() {
             o.remove(name);

crates/engine/tests/custom_view_freeze.rs

@@ -0,0 +1,28 @@
+use gridcraft_engine::Session;
+use serde_json::json;
+
+fn freeze(s: &Session) -> Option<(u32, u32)> {
+    s.doc().unwrap().wb.active().unwrap().freeze
+}
+
+#[test]
+fn showing_a_custom_view_restores_its_frozen_panes() {
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("view.freezePanes", json!({"cell": "B2"})).unwrap();
+    s.execute("view.customViews", json!({"save": "Frozen"})).unwrap();
+    s.execute("view.unfreezePanes", json!({})).unwrap();
+    assert_eq!(freeze(&s), None);
+    s.execute("view.customViews", json!({"show": "Frozen"})).unwrap();
+    assert_eq!(freeze(&s), Some((1, 1)));
+}
+
+#[test]
+fn showing_an_unfrozen_custom_view_clears_current_panes() {
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("view.customViews", json!({"save": "Plain"})).unwrap();
+    s.execute("view.freezePanes", json!({"cell": "B2"})).unwrap();
+    s.execute("view.customViews", json!({"show": "Plain"})).unwrap();
+    assert_eq!(freeze(&s), None);
+}