refactor context menu and keyboard navigation handling for improved clarity and maintainability

dicom-viewer/src/App.tsx

@@ -1174,17 +1174,17 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
     };
   }, []);
 
-useEffect(() => {
-  const el = appRootRef.current;
-  if (!el) return;
-  const handleContextMenu = (e: MouseEvent) => {
-    e.preventDefault();
-  };
-  el.addEventListener("contextmenu", handleContextMenu);
-  return () => {
-    el.removeEventListener("contextmenu", handleContextMenu);
-  };
-}, []);
+  useEffect(() => {
+    const el = appRootRef.current;
+    if (!el) return;
+    const handleContextMenu = (e: MouseEvent) => {
+      e.preventDefault();
+    };
+    el.addEventListener("contextmenu", handleContextMenu);
+    return () => {
+      el.removeEventListener("contextmenu", handleContextMenu);
+    };
+  }, []);
 
   useEffect(() => {
     if (!referenceLinesEnabled) return;
@@ -1926,6 +1926,8 @@ useEffect(() => {
 
 
   useEffect(() => {
+    const el = appRootRef.current;
+    if (!el) return;
     function handleArrowKeyNavigation(e: KeyboardEvent) {
       console.log("Handling arrow key navigation", e.key);
       console.log("activeViewport", activeViewport);
@@ -1975,8 +1977,11 @@ useEffect(() => {
       }
     }
 
-    window.addEventListener("keydown", handleArrowKeyNavigation);
-    return () => window.removeEventListener("keydown", handleArrowKeyNavigation);
+    el.addEventListener("keydown", handleArrowKeyNavigation);
+
+    return () => {
+      el.removeEventListener("keydown", handleArrowKeyNavigation);
+    };
   }, [activeViewport, viewportModes, viewportImageIds, updateOverlay]);
 
 
@@ -2401,98 +2406,98 @@ useEffect(() => {
         </div>
 
         {/* Preset menu (bottom right of viewport) */}
-<div
-  style={{
-    position: "absolute",
-    right: 8,
-    bottom: 8,
-    zIndex: 10,
-    pointerEvents: "auto", // <-- ensure pointer events are enabled
-  }}
->
-  <div
-    className="preset-menu"
-    style={{
-      background: "rgba(0,0,0,0.7)",
-      color: "#fff",
-      borderRadius: "4px",
-      fontSize: "14px",
-      minWidth: "120px",
-      overflow: "hidden",
-      cursor: "pointer",
-      position: "relative",
-      boxShadow: presetsOpenArr[i] ? "0 2px 8px rgba(0,0,0,0.3)" : undefined,
-      pointerEvents: "auto", // <-- ensure pointer events are enabled
-    }}
-    onClick={e => e.stopPropagation()} // <-- prevent bubbling to viewport
-  >
-    <div
-      style={{
-        padding: "6px 12px",
-        fontWeight: "bold",
-        userSelect: "none",
-      }}
-      onClick={e => {
-        e.stopPropagation(); // <-- prevent bubbling to viewport
-        setPresetsOpenArr(prev => {
-          const next = [...prev];
-          next[i] = !next[i];
-          return next;
-        });
-      }}
-    >
-      Presets
-      <span style={{ float: "right", fontWeight: "normal" }}>
-        {presetsOpenArr[i] ? "▲" : "▼"}
-      </span>
-    </div>
-    {presetsOpenArr[i] && (
-      <div
-        className="preset-menu-content"
-        style={{
-          background: "rgba(0,0,0,0.95)",
-          borderRadius: "0 0 4px 4px",
-          padding: "6px 0 6px 0",
-          display: "flex",
-          flexDirection: "column",
-          zIndex: 11,
-          pointerEvents: "auto", // <-- ensure pointer events are enabled
-        }}
-        onClick={e => e.stopPropagation()} // <-- prevent bubbling to viewport
-      >
-        {WINDOW_LEVEL_PRESETS.map((preset) => (
-          <button
-            key={preset.name}
+        <div
+          style={{
+            position: "absolute",
+            right: 8,
+            bottom: 8,
+            zIndex: 10,
+            pointerEvents: "auto", // <-- ensure pointer events are enabled
+          }}
+        >
+          <div
+            className="preset-menu"
             style={{
-              display: "block",
-              width: "100%",
-              margin: "2px 0",
-              background: "#333",
+              background: "rgba(0,0,0,0.7)",
               color: "#fff",
-              border: "none",
-              borderRadius: "3px",
+              borderRadius: "4px",
+              fontSize: "14px",
+              minWidth: "120px",
+              overflow: "hidden",
               cursor: "pointer",
-              padding: "4px 0",
-              fontSize: "13px",
-              opacity: 0.9,
-            }}
-            onClick={e => {
-              e.stopPropagation(); // <-- prevent bubbling to viewport
-              handleApplyPreset(i, preset.center, preset.width);
-              setPresetsOpenArr(prev => {
-                const next = [...prev];
-                next[i] = false;
-                return next;
-              });
+              position: "relative",
+              boxShadow: presetsOpenArr[i] ? "0 2px 8px rgba(0,0,0,0.3)" : undefined,
+              pointerEvents: "auto", // <-- ensure pointer events are enabled
             }}
+            onClick={e => e.stopPropagation()} // <-- prevent bubbling to viewport
           >
-            {preset.name}
-          </button>
-        ))}
-      </div>
-    )}
-  </div>
-</div>
+            <div
+              style={{
+                padding: "6px 12px",
+                fontWeight: "bold",
+                userSelect: "none",
+              }}
+              onClick={e => {
+                e.stopPropagation(); // <-- prevent bubbling to viewport
+                setPresetsOpenArr(prev => {
+                  const next = [...prev];
+                  next[i] = !next[i];
+                  return next;
+                });
+              }}
+            >
+              Presets
+              <span style={{ float: "right", fontWeight: "normal" }}>
+                {presetsOpenArr[i] ? "▲" : "▼"}
+              </span>
+            </div>
+            {presetsOpenArr[i] && (
+              <div
+                className="preset-menu-content"
+                style={{
+                  background: "rgba(0,0,0,0.95)",
+                  borderRadius: "0 0 4px 4px",
+                  padding: "6px 0 6px 0",
+                  display: "flex",
+                  flexDirection: "column",
+                  zIndex: 11,
+                  pointerEvents: "auto", // <-- ensure pointer events are enabled
+                }}
+                onClick={e => e.stopPropagation()} // <-- prevent bubbling to viewport
+              >
+                {WINDOW_LEVEL_PRESETS.map((preset) => (
+                  <button
+                    key={preset.name}
+                    style={{
+                      display: "block",
+                      width: "100%",
+                      margin: "2px 0",
+                      background: "#333",
+                      color: "#fff",
+                      border: "none",
+                      borderRadius: "3px",
+                      cursor: "pointer",
+                      padding: "4px 0",
+                      fontSize: "13px",
+                      opacity: 0.9,
+                    }}
+                    onClick={e => {
+                      e.stopPropagation(); // <-- prevent bubbling to viewport
+                      handleApplyPreset(i, preset.center, preset.width);
+                      setPresetsOpenArr(prev => {
+                        const next = [...prev];
+                        next[i] = false;
+                        return next;
+                      });
+                    }}
+                  >
+                    {preset.name}
+                  </button>
+                ))}
+              </div>
+            )}
+          </div>
+        </div>
         {/* Position bar inside each viewport */}
         {viewportModes[i] === "stack" && viewportImageIds[i] && (
           <div
@@ -2856,18 +2861,18 @@ useEffect(() => {
 
   return (
     // App root
-    <div 
-    ref={appRootRef}
-    style={{
-      position: "relative",
-      inset: 0,
-      width: "100%",
-      height: "100%",
-      boxSizing: "border-box",
-      background: "#222",
-      padding: "12px",
-      overflow: "hidden",
-    }}>
+    <div
+      ref={appRootRef}
+      style={{
+        position: "relative",
+        inset: 0,
+        width: "100%",
+        height: "100%",
+        boxSizing: "border-box",
+        background: "#222",
+        padding: "12px",
+        overflow: "hidden",
+      }}>
       {/* Loading overlay */}
       {loadingState && (
         <div
@@ -3086,23 +3091,23 @@ useEffect(() => {
                   ? "Disable Alt Key for Reference Cursors"
                   : "Enable Alt Key for Reference Cursors"}
               </button>
-      <button
-        style={{
-          padding: "10px 18px",
-          background: annotationNavEnabled ? "#1976d2" : "#333",
-          color: "#fff",
-          border: "none",
-          borderRadius: "4px",
-          fontWeight: "bold",
-          cursor: "pointer",
-          fontSize: "15px",
-          marginBottom: "18px",
-          width: "100%",
-        }}
-        onClick={() => setAnnotationNavEnabled((prev) => !prev)}
-      >
-        {annotationNavEnabled ? "Hide" : "Show"} Annotation Navigation
-      </button>
+              <button
+                style={{
+                  padding: "10px 18px",
+                  background: annotationNavEnabled ? "#1976d2" : "#333",
+                  color: "#fff",
+                  border: "none",
+                  borderRadius: "4px",
+                  fontWeight: "bold",
+                  cursor: "pointer",
+                  fontSize: "15px",
+                  marginBottom: "18px",
+                  width: "100%",
+                }}
+                onClick={() => setAnnotationNavEnabled((prev) => !prev)}
+              >
+                {annotationNavEnabled ? "Hide" : "Show"} Annotation Navigation
+              </button>
               {/* Add more menu items here if needed */}
 
             </div>