Fixes #1785. Adds Pos.Align - Align sets of views horizontally or vertically

Terminal.Gui/Drawing/Thickness.cs

@@ -232,8 +232,8 @@ rect with
             var tf = new TextFormatter
             {
                 Text = label is null ? string.Empty : $"{label} {this}",
-                Alignment = TextAlignment.Centered,
-                VerticalAlignment = VerticalTextAlignment.Bottom,
+                Alignment = Alignment.Centered,
+                VerticalAlignment = Alignment.Bottom,
                 AutoSize = true
             };
             tf.Draw (rect, Application.Driver.CurrentAttribute, Application.Driver.CurrentAttribute, rect);

Terminal.Gui/Resources/config.json

@@ -24,7 +24,7 @@
   "Themes": [
     {
       "Default": {
-        "Dialog.DefaultButtonAlignment": "Center",
+        "Dialog.DefaultButtonAlignment": "Right",
         "FrameView.DefaultBorderStyle": "Single",
         "Window.DefaultBorderStyle": "Single",
         "ColorSchemes": [

Terminal.Gui/View/Layout/PosDim.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using static Terminal.Gui.Dim;
 
 namespace Terminal.Gui;
 
@@ -45,6 +46,14 @@ namespace Terminal.Gui;
 ///             </item>
 ///             <item>
 ///                 <term>
+///                     <see cref="Pos.Align()"/>
+///                 </term>
+///                 <description>
+///                     Creates a <see cref="Pos"/> object that aligns a set of views.
+///                 </description>
+///             </item>
+///             <item>
+///                 <term>
 ///                     <see cref="Pos.AnchorEnd()"/>
 ///                 </term>
 ///                 <description>
@@ -203,6 +212,15 @@ public static Pos AnchorEnd (int offset)
     /// <returns>The <see cref="Pos"/> returned from the function.</returns>
     public static Pos Function (Func<int> function) { return new PosFunc (function); }
 
+
+    /// <summary>
+    ///      Creates a <see cref="Pos"/> object that aligns a set of views according to the specified alignment setting.
+    /// </summary>
+    /// <param name="alignment"></param>
+    /// <param name="groupId">The optional, unique identifier for the set of views to align according to <paramref name="alignment"/>.</param>
+    /// <returns></returns>
+    public static Pos Align (Alignment alignment, int groupId = 0) { return new PosAlign (alignment, groupId); }
+
     /// <summary>Serves as the default hash function. </summary>
     /// <returns>A hash code for the current object.</returns>
     public override int GetHashCode () { return Anchor (0).GetHashCode (); }
@@ -484,6 +502,173 @@ internal class PosFactor (float factor) : Pos
         internal override int Anchor (int width) { return (int)(width * _factor); }
     }
 
+
+    /// <summary>
+    /// Enables alignment of a set of views.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    ///     The Group ID is used to identify a set of views that should be alignment together. When only a single
+    ///     set of views is aligned, setting the Group ID is not needed because it defaults to 0.
+    /// </para>
+    /// <para>
+    ///     The first view added to the Superview with a given Group ID is used to determine the alignment of the group.
+    ///     The alignment is applied to all views with the same Group ID.
+    /// </para>
+    /// </remarks>
+    public class PosAlign : Pos
+    {
+        /// <summary>
+        /// The cached location. Used to store the calculated location to avoid recalculating it.
+        /// </summary>
+        private int? _location;
+
+        /// <summary>
+        /// Gets the identifier of a set of views that should be aligned together. When only a single
+        /// set of views is aligned, setting the <see cref="_groupId"/> is not needed because it defaults to 0.
+        /// </summary>
+        private readonly int _groupId;
+
+        /// <summary>
+        /// Gets the alignment settings.
+        /// </summary>
+        public Aligner Aligner { get; } = new ();
+
+
+        /// <summary>
+        /// Aligns the views in <paramref name="views"/> that have the same group ID as <paramref name="groupId"/>.
+        /// </summary>
+        /// <param name="groupId"></param>
+        /// <param name="views"></param>
+        /// <param name="dimension"></param>
+        /// <param name="size"></param>
+        private static void AlignGroup (int groupId, IList<View> views, Dim.Dimension dimension, int size)
+        {
+            if (views is null)
+            {
+                return;
+            }
+            Aligner firstInGroup = null;
+            List<int> dimensionsList = new ();
+            List<View> viewsInGroup = views.Where (
+                                                   v =>
+                                                   {
+                                                       if (dimension == Dimension.Width && v.X is PosAlign alignX)
+                                                       {
+                                                           return alignX._groupId == groupId;
+                                                       }
+
+                                                       if (dimension == Dimension.Height && v.Y is PosAlign alignY)
+                                                       {
+                                                           return alignY._groupId == groupId;
+                                                       }
+
+                                                       return false;
+                                                   }).ToList ();
+            if (viewsInGroup.Count == 0)
+            {
+                return;
+            }
+
+            foreach (var view in viewsInGroup)
+            {
+                var posAlign = dimension == Dimension.Width ? view.X as PosAlign : view.Y as PosAlign;
+
+                if (posAlign is { })
+                {
+                    if (firstInGroup is null)
+                    {
+                        firstInGroup = posAlign.Aligner;
+                    }
+
+                    dimensionsList.Add (dimension == Dimension.Width ? view.Frame.Width : view.Frame.Height);
+                }
+            }
+
+            if (firstInGroup is null)
+            {
+                return;
+            }
+
+            firstInGroup.ContainerSize = size;
+            var locations = firstInGroup.Align (dimensionsList.ToArray ());
+
+            for (var index = 0; index < viewsInGroup.Count; index++)
+            {
+                View view = viewsInGroup [index];
+                PosAlign align = dimension == Dimension.Width ? view.X as PosAlign : view.Y as PosAlign;
+
+                if (align is { })
+                {
+                    align._location = locations [index];
+                }
+            }
+        }
+
+        /// <summary>
+        /// Enables alignment of a set of views.
+        /// </summary>
+        /// <param name="alignment"></param>
+        /// <param name="groupId">The unique identifier for the set of views to align according to <paramref name="alignment"/>.</param>
+        public PosAlign (Alignment alignment, int groupId = 0)
+        {
+            Aligner.PutSpaceBetweenItems = true;
+            Aligner.Alignment = alignment;
+            _groupId = groupId;
+            Aligner.PropertyChanged += Aligner_PropertyChanged;
+        }
+
+        private void Aligner_PropertyChanged (object sender, System.ComponentModel.PropertyChangedEventArgs e)
+        {
+            _location = null;
+        }
+
+        /// <inheritdoc />
+        public override bool Equals (object other)
+        {
+            return other is PosAlign align && _groupId == align._groupId && _location == align._location && align.Aligner.Alignment == Aligner.Alignment;
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode ()
+        {
+            return Aligner.GetHashCode () ^ _groupId.GetHashCode ();
+        }
+
+        /// <inheritdoc />
+        public override string ToString ()
+        {
+            return $"Align(groupId={_groupId}, alignment={Aligner.Alignment})";
+        }
+
+        internal override int Anchor (int width)
+        {
+            return _location ?? 0 - width;
+        }
+
+        internal override int Calculate (int superviewDimension, Dim dim, View us, Dim.Dimension dimension)
+        {
+            if (_location.HasValue && Aligner.ContainerSize == superviewDimension)
+            {
+                return _location.Value;
+            }
+
+            if (us?.SuperView is null)
+            {
+                return 0;
+            }
+
+            AlignGroup (_groupId, us.SuperView.Subviews, dimension, superviewDimension);
+
+            if (_location.HasValue)
+            {
+                return _location.Value;
+            }
+
+            return 0;
+        }
+
+    }
     // Helper class to provide dynamic value by the execution of a function that returns an integer.
     internal class PosFunc (Func<int> n) : Pos
     {

Terminal.Gui/View/ViewText.cs

@@ -87,7 +87,7 @@ public void OnTextChanged (string oldValue, string newValue)
     ///     <para> <see cref="View.Width"/> or <see cref="View.Height"/> are using <see cref="Dim.DimAutoStyle.Text"/>, the <see cref="ContentSize"/> will be adjusted to fit the text.</para>
     /// </remarks>
     /// <value>The text alignment.</value>
-    public virtual TextAlignment TextAlignment
+    public virtual Alignment TextAlignment
     {
         get => TextFormatter.Alignment;
         set
@@ -105,7 +105,7 @@ public virtual TextAlignment TextAlignment
     /// <remarks>
     ///     <para> <see cref="View.Width"/> or <see cref="View.Height"/> are using <see cref="Dim.DimAutoStyle.Text"/>, the <see cref="ContentSize"/> will be adjusted to fit the text.</para>
     /// </remarks>
-    /// <value>The text alignment.</value>
+    /// <value>The text direction.</value>
     public virtual TextDirection TextDirection
     {
         get => TextFormatter.Direction;
@@ -129,8 +129,8 @@ public virtual TextDirection TextDirection
     /// <remarks>
     ///     <para> <see cref="View.Width"/> or <see cref="View.Height"/> are using <see cref="Dim.DimAutoStyle.Text"/>, the <see cref="ContentSize"/> will be adjusted to fit the text.</para>
     /// </remarks>
-    /// <value>The text alignment.</value>
-    public virtual VerticalTextAlignment VerticalTextAlignment
+    /// <value>The vertical text alignment.</value>
+    public virtual Alignment VerticalTextAlignment
     {
         get => TextFormatter.VerticalAlignment;
         set

Terminal.Gui/Views/Button.cs

@@ -37,15 +37,15 @@ public class Button : View
     /// <remarks>The width of the <see cref="Button"/> is computed based on the text length. The height will always be 1.</remarks>
     public Button ()
     {
-        TextAlignment = TextAlignment.Centered;
-        VerticalTextAlignment = VerticalTextAlignment.Middle;
+        TextAlignment = Alignment.Centered;
+        VerticalTextAlignment = Alignment.Centered;
 
         _leftBracket = Glyphs.LeftBracket;
         _rightBracket = Glyphs.RightBracket;
         _leftDefault = Glyphs.LeftDefaultIndicator;
         _rightDefault = Glyphs.RightDefaultIndicator;
 
-        Height = 1;
+        Height = Dim.Auto (Dim.DimAutoStyle.Text);
         Width = Dim.Auto (Dim.DimAutoStyle.Text);
 
         CanFocus = true;

Terminal.Gui/Views/CheckBox.cs

@@ -155,13 +155,13 @@ protected override void UpdateTextFormatterText ()
     {
         switch (TextAlignment)
         {
-            case TextAlignment.Left:
-            case TextAlignment.Centered:
-            case TextAlignment.Justified:
+            case Alignment.Left:
+            case Alignment.Centered:
+            case Alignment.Justified:
                 TextFormatter.Text = $"{GetCheckedState ()} {GetFormatterText ()}";
 
                 break;
-            case TextAlignment.Right:
+            case Alignment.Right:
                 TextFormatter.Text = $"{GetFormatterText ()} {GetCheckedState ()}";
 
                 break;