Added FlowModes enum

Terminal.Gui/Drawing/FlowModes.cs

@@ -0,0 +1,31 @@
+namespace Terminal.Gui;
+
+/// <summary>
+///     Determines how items will be arranged in a container when alignment is <see cref="Alignment.Start"/> or <see cref="Alignment.End"/>,
+/// </summary>
+[Flags]
+public enum FlowModes
+{
+    /// <summary>
+    ///     The items will be arranged from start (left/top) to end (right/bottom).
+    /// </summary>
+    StartToEnd = 0,
+
+    /// <summary>
+    ///     The items will be arranged from end (right/bottom) to start (left/top).
+    /// </summary>
+    /// <remarks>
+    ///     Not implemented.
+    /// </remarks>
+    EndToStart = 1,
+
+    /// <summary>
+    ///    When aligning via <see cref="Alignment.Start"/> or <see cref="Alignment.End"/>, the first item will be aligned at the opposite end.
+    /// </summary>
+    IgnoreFirst = 2,
+
+    /// <summary>
+    ///    When aligning via <see cref="Alignment.Start"/> or <see cref="Alignment.End"/>, the last item will be aligned at the opposite end.
+    /// </summary>
+    IgnoreLast = 4,
+}