modified CaretNative

CursorLang/Interop/CaretNative.cs

@@ -65,12 +65,21 @@ internal static class CaretNative
             return caret;
         }
 
+        return Validate(caret, window, GetDpiForWindow(hwndFocus) / 96.0);
+    }
+
+    /// <summary>
+    /// The same check over plain numbers: the input window bounds and the scale of
+    /// its monitor are already known.
+    /// </summary>
+    internal static PopupWindowNative.Rect? Validate(
+        PopupWindowNative.Rect caret, PopupWindowNative.Rect window, double scale)
+    {
         if (IsInside(caret, window))
         {
             return caret;
         }
 
-        double scale = GetDpiForWindow(hwndFocus) / 96.0;
         var scaled = new PopupWindowNative.Rect
         {
             Left = (int)(caret.Left * scale),
@@ -82,7 +91,7 @@ internal static class CaretNative
         return IsInside(scaled, window) ? scaled : null;
     }
 
-    private static bool IsInside(PopupWindowNative.Rect inner, PopupWindowNative.Rect outer) =>
+    internal static bool IsInside(PopupWindowNative.Rect inner, PopupWindowNative.Rect outer) =>
         inner.Left >= outer.Left && inner.Right <= outer.Right &&
         inner.Top >= outer.Top && inner.Bottom <= outer.Bottom;