Merge pull request #3376 from tig/v2_2144-3D-effect

Fixes #2114. Adds `View.ShadowStyle` - Enabled but not turned on by default

Terminal.Gui/Application/Application.cs

@@ -973,6 +973,7 @@ public static void RunIteration (ref RunState state, ref bool firstIteration)
 
         if (state.Toplevel.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || OverlappedChildNeedsDisplay ())
         {
+            state.Toplevel.SetNeedsDisplay();
             state.Toplevel.Draw ();
             Driver.UpdateScreen ();
 

Terminal.Gui/Configuration/ConfigurationManager.cs

@@ -4,6 +4,7 @@
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
+using System.Runtime.Versioning;
 using System.Text.Encodings.Web;
 using System.Text.Json;
 using System.Text.Json.Serialization;
@@ -49,6 +50,7 @@ namespace Terminal.Gui;
 ///         Lowest Precedence.
 ///     </para>
 /// </summary>
+[ComponentGuarantees (ComponentGuaranteesOptions.None)]
 public static class ConfigurationManager
 {
     /// <summary>

Terminal.Gui/Drawing/Cell.cs

@@ -4,18 +4,19 @@
 ///     Represents a single row/column in a Terminal.Gui rendering surface (e.g. <see cref="LineCanvas"/> and
 ///     <see cref="ConsoleDriver"/>).
 /// </summary>
-public class Cell
+public record struct Cell ()
 {
-    private Rune _rune;
 
     /// <summary>The attributes to use when drawing the Glyph.</summary>
-    public Attribute? Attribute { get; set; }
+    public Attribute? Attribute { get; set; } = null;
 
     /// <summary>
     ///     Gets or sets a value indicating whether this <see cref="T:Terminal.Gui.Cell"/> has been modified since the
     ///     last time it was drawn.
     /// </summary>
-    public bool IsDirty { get; set; }
+    public bool IsDirty { get; set; } = false;
+
+    private Rune _rune = default;
 
     /// <summary>The character to display. If <see cref="Rune"/> is <see langword="null"/>, then <see cref="Rune"/> is ignored.</summary>
     public Rune Rune

Terminal.Gui/Drawing/Color.cs

@@ -259,6 +259,27 @@ public Color GetHighlightColor ()
 
     }
 
+    /// <summary>
+    /// Gets a color that is the same hue as the current color, but with a different lightness.
+    /// </summary>
+    /// <returns></returns>
+    public Color GetDarkerColor ()
+    {
+        // TODO: This is a temporary implementation; just enough to show how it could work. 
+        var hsl = ColorHelper.ColorConverter.RgbToHsl (new RGB (R, G, B));
+
+        var amount = .3;
+        if (hsl.L <= 5)
+        {
+            return DarkGray;
+        }
+        hsl.L = (byte)(hsl.L * amount);
+
+        var rgb = ColorHelper.ColorConverter.HslToRgb (hsl);
+        return new (rgb.R, rgb.G, rgb.B);
+
+    }
+
     #region Legacy Color Names
 
     /// <summary>The black color.</summary>

Terminal.Gui/Drawing/Glyphs.cs

@@ -437,4 +437,24 @@ public class GlyphDefinitions
     public Rune CrossHv { get; set; } = (Rune)'╋';
 
     #endregion
+
+    #region ----------------- ShadowStyle -----------------
+
+
+    /// <summary>Shadow - Vertical Start - Left Half Block - ▌ U+0258c</summary>
+    public Rune ShadowVerticalStart { get; set; } =  (Rune)'▌'; // Half: '\u2596'  ▖;
+
+    /// <summary>Shadow - Vertical - Left Half Block - ▌ U+0258c</summary>
+    public Rune ShadowVertical { get; set; } = (Rune)'▌';
+
+    /// <summary>Shadow - Horizontal Start - Upper Half Block - ▀ U+02580</summary>
+    public Rune ShadowHorizontalStart { get; set; } = (Rune)'▀'; // Half: ▝ U+0259d;
+
+    /// <summary>Shadow - Horizontal - Upper Half Block - ▀ U+02580</summary>
+    public Rune ShadowHorizontal { get; set; } = (Rune)'▀';
+
+    /// <summary>Shadow - Horizontal End - Quadrant Upper Left - ▘ U+02598</summary>
+    public Rune ShadowHorizontalEnd { get; set; } = (Rune)'▘';
+
+    #endregion
 }

Terminal.Gui/Drawing/LineCanvas.cs

@@ -165,9 +165,9 @@ public void Clear ()
     ///     intersection symbols.
     /// </summary>
     /// <returns>A map of all the points within the canvas.</returns>
-    public Dictionary<Point, Cell> GetCellMap ()
+    public Dictionary<Point, Cell?> GetCellMap ()
     {
-        Dictionary<Point, Cell> map = new ();
+        Dictionary<Point, Cell?> map = new ();
 
         // walk through each pixel of the bitmap
         for (int y = Viewport.Y; y < Viewport.Y + Viewport.Height; y++)

Terminal.Gui/Resources/config.json

@@ -20,6 +20,7 @@
   "Application.AlternateBackwardKey": "Ctrl+PageUp",
   "Application.AlternateForwardKey": "Ctrl+PageDown",
   "Application.QuitKey": "Esc",
+
   "Theme": "Default",
   "Themes": [
     {
@@ -28,6 +29,9 @@
         "Dialog.DefaultButtonAlignmentModes": "AddSpaceBetweenItems",
         "FrameView.DefaultBorderStyle": "Single",
         "Window.DefaultBorderStyle": "Single",
+        "Dialog.DefaultBorderStyle": "Single",
+        "MessageBox.DefaultBorderStyle": "Double",
+        "Button.DefaultShadow": "None",
         "ColorSchemes": [
           {
             "TopLevel": {

Terminal.Gui/View/Adornment/Margin.cs

@@ -1,4 +1,8 @@
-namespace Terminal.Gui;
+#nullable enable
+
+using System.Drawing;
+
+namespace Terminal.Gui;
 
 /// <summary>The Margin for a <see cref="View"/>.</summary>
 /// <remarks>
@@ -15,6 +19,102 @@ public Margin ()
     public Margin (View parent) : base (parent)
     {
         /* Do nothing; View.CreateAdornment requires a constructor that takes a parent */
+
+        HighlightStyle |= HighlightStyle.Pressed;
+        Highlight += Margin_Highlight;
+        LayoutStarted += Margin_LayoutStarted;
+
+        // Margin should not be focusable
+        CanFocus = false;
+    }
+
+    private void Margin_LayoutStarted (object? sender, LayoutEventArgs e)
+    {
+        // Adjust the shadow such that it is drawn aligned with the Border
+        if (ShadowStyle != Gui.ShadowStyle.None && _rightShadow is { } && _bottomShadow is { })
+        {
+            _rightShadow.Y = Parent.Border.Thickness.Top > 0 ? Parent.Border.Thickness.Top - (Parent.Border.Thickness.Top > 2 && Parent.Border.ShowTitle ? 1 : 0) : 1;
+            _bottomShadow.X = Parent.Border.Thickness.Left > 0 ? Parent.Border.Thickness.Left : 1;
+        }
+    }
+
+    private bool _pressed;
+    private void Margin_Highlight (object? sender, HighlightEventArgs e)
+    {
+        if (ShadowStyle != Gui.ShadowStyle.None)
+        {
+            if (_pressed && e.HighlightStyle == HighlightStyle.None)
+            {
+                Thickness = new (Thickness.Left - 1, Thickness.Top, Thickness.Right + 1, Thickness.Bottom);
+
+                if (_rightShadow is { })
+                {
+                    _rightShadow.Visible = true;
+                }
+
+                if (_bottomShadow is { })
+                {
+                    _bottomShadow.Visible = true;
+                }
+
+                _pressed = false;
+                return;
+            }
+
+            if (!_pressed && (e.HighlightStyle.HasFlag (HighlightStyle.Pressed) /*|| e.HighlightStyle.HasFlag (HighlightStyle.PressedOutside)*/))
+            {
+                Thickness = new (Thickness.Left + 1, Thickness.Top, Thickness.Right - 1, Thickness.Bottom);
+                _pressed = true;
+                if (_rightShadow is { })
+                {
+                    _rightShadow.Visible = false;
+                }
+
+                if (_bottomShadow is { })
+                {
+                    _bottomShadow.Visible = false;
+                }
+            }
+        }
+
+    }
+
+    /// <inheritdoc />
+    public override void OnDrawContent (Rectangle viewport)
+    {
+        Rectangle screen = ViewportToScreen (viewport);
+        Attribute normalAttr = GetNormalColor ();
+
+        Driver?.SetAttribute (normalAttr);
+
+
+        // This just draws/clears the thickness, not the insides.
+        if (ShadowStyle != ShadowStyle.None)
+        {
+            screen = Rectangle.Inflate (screen, -1, -1);
+        }
+        Thickness.Draw (screen, ToString ());
+
+        if (Subviews.Count > 0)
+        {
+            // Draw subviews
+            // TODO: Implement OnDrawSubviews (cancelable);
+            if (Subviews is { } && SubViewNeedsDisplay)
+            {
+                IEnumerable<View> subviewsNeedingDraw = Subviews.Where (
+                                                                        view => view.Visible
+                                                                                && (view.NeedsDisplay || view.SubViewNeedsDisplay || view.LayoutNeeded)
+                                                                       );
+                foreach (View view in subviewsNeedingDraw)
+                {
+                    if (view.LayoutNeeded)
+                    {
+                        view.LayoutSubviews ();
+                    }
+                    view.Draw ();
+                }
+            }
+        }
     }
 
     /// <summary>
@@ -30,12 +130,93 @@ public override ColorScheme ColorScheme
                 return base.ColorScheme;
             }
 
-            return Parent?.SuperView?.ColorScheme ?? Colors.ColorSchemes ["TopLevel"];
+            return (Parent?.SuperView?.ColorScheme ?? Colors.ColorSchemes ["TopLevel"])!;
         }
         set
         {
             base.ColorScheme = value;
             Parent?.SetNeedsDisplay ();
         }
     }
-}
+
+    /// <inheritdoc />
+    public override ShadowStyle ShadowStyle
+    {
+        get => base.ShadowStyle;
+        set
+        {
+            base.ShadowStyle = SetShadow (value);
+        }
+    }
+
+    /// <summary>
+    ///    Sets whether the Margin includes a shadow effect. The shadow is drawn on the right and bottom sides of the
+    ///     Margin.
+    /// </summary>
+    public ShadowStyle SetShadow (ShadowStyle style)
+    {
+        if (ShadowStyle == style)
+        {
+            // return style;
+        }
+
+        if (ShadowStyle != ShadowStyle.None)
+        {
+            // Turn off shadow
+            Thickness = new (Thickness.Left, Thickness.Top, Thickness.Right - 1, Thickness.Bottom - 1);
+        }
+
+        if (style != ShadowStyle.None)
+        {
+            // Turn on shadow
+            Thickness = new (Thickness.Left, Thickness.Top, Thickness.Right + 1, Thickness.Bottom + 1);
+        }
+
+        if (_rightShadow is { })
+        {
+            _rightShadow.ShadowStyle = style;
+        }
+
+        if (_bottomShadow is { })
+        {
+            _bottomShadow.ShadowStyle = style;
+        }
+        return style;
+    }
+
+    private ShadowView? _bottomShadow;
+    private ShadowView? _rightShadow;
+
+    /// <inheritdoc/>
+    public override void BeginInit ()
+    {
+        base.BeginInit ();
+
+        if (Parent is null)
+        {
+            return;
+        }
+
+        ShadowStyle = base.ShadowStyle;
+        Add (
+             _rightShadow = new ShadowView
+             {
+                 X = Pos.AnchorEnd (1),
+                 Y = 0,
+                 Width = 1,
+                 Height = Dim.Fill (),
+                 ShadowStyle = ShadowStyle,
+                 Orientation = Orientation.Vertical
+             },
+             _bottomShadow = new ShadowView
+             {
+                 X = 0,
+                 Y = Pos.AnchorEnd (1),
+                 Width = Dim.Fill (),
+                 Height = 1,
+                 ShadowStyle = ShadowStyle,
+                 Orientation = Orientation.Horizontal
+             }
+            );
+    }
+}

Terminal.Gui/View/Adornment/ShadowStyle.cs

@@ -0,0 +1,22 @@
+namespace Terminal.Gui;
+
+/// <summary>
+///     Defines the style of shadow to be drawn on the right and bottom sides of the <see cref="View"/>.
+/// </summary>
+public enum ShadowStyle
+{
+    /// <summary>
+    ///     No shadow.
+    /// </summary>
+    None,
+
+    /// <summary>
+    ///     A shadow that is drawn using block elements. Ideal for smaller views such as buttons.
+    /// </summary>
+    Opaque,
+
+    /// <summary>
+    ///     A shadow that is drawn using the underlying text with a darker background. Ideal for larger views such as windows.
+    /// </summary>
+    Transparent
+}