From 5618cc03e46c044f083c3880be44ad072a7dffb0 Mon Sep 17 00:00:00 2001
From: Brett Story <brettmstory@gmail.com>
Date: Sun, 15 May 2022 11:03:02 -0500
Subject: [PATCH] Utilizing TextLayout's LineHeight in TextBox and
 TextPresenter

---
 samples/ControlCatalog/Pages/TextBoxPage.xaml |  6 +++++
 .../Presenters/TextPresenter.cs               | 25 +++++++++++++++----
 src/Avalonia.Controls/TextBox.cs              | 19 ++++++++++++--
 .../Controls/TextBox.xaml                     |  1 +
 .../Controls/TextBox.xaml                     |  1 +
 5 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/samples/ControlCatalog/Pages/TextBoxPage.xaml b/samples/ControlCatalog/Pages/TextBoxPage.xaml
index dec5f74da8..e3d0c5e4e2 100644
--- a/samples/ControlCatalog/Pages/TextBoxPage.xaml
+++ b/samples/ControlCatalog/Pages/TextBoxPage.xaml
@@ -66,6 +66,12 @@
                  FontFamily="Comic Sans MS"
                  InputMethod.IsInputMethodEnabled="False"
                  Foreground="Red"/>
+        <TextBox AcceptsReturn="True" 
+                 TextWrapping="Wrap" 
+                 Width="200" 
+                 Height="125"
+                 LineHeight="32"
+                 Text="Multiline TextBox with TextWrapping and increased LineHeight.&#xD;&#xD;Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est." />
       </StackPanel>
       <StackPanel Orientation="Vertical" Spacing="8" Margin="8">
         <Label Classes="h2" Target="{Binding #firstResMFont}">res_m fonts</Label>
diff --git a/src/Avalonia.Controls/Presenters/TextPresenter.cs b/src/Avalonia.Controls/Presenters/TextPresenter.cs
index 07061940b5..b0f8752d65 100644
--- a/src/Avalonia.Controls/Presenters/TextPresenter.cs
+++ b/src/Avalonia.Controls/Presenters/TextPresenter.cs
@@ -33,7 +33,7 @@ namespace Avalonia.Controls.Presenters
 
         public static readonly StyledProperty<IBrush?> CaretBrushProperty =
             AvaloniaProperty.Register<TextPresenter, IBrush?>(nameof(CaretBrush));
-
+        
         public static readonly DirectProperty<TextPresenter, int> SelectionStartProperty =
             TextBox.SelectionStartProperty.AddOwner<TextPresenter>(
                 o => o.SelectionStart,
@@ -43,7 +43,7 @@ namespace Avalonia.Controls.Presenters
             TextBox.SelectionEndProperty.AddOwner<TextPresenter>(
                 o => o.SelectionEnd,
                 (o, v) => o.SelectionEnd = v);
-
+        
         /// <summary>
         /// Defines the <see cref="Text"/> property.
         /// </summary>
@@ -65,6 +65,12 @@ namespace Avalonia.Controls.Presenters
         public static readonly StyledProperty<TextWrapping> TextWrappingProperty =
             TextBlock.TextWrappingProperty.AddOwner<TextPresenter>();
 
+        /// <summary>
+        /// Defines the <see cref="LineHeight"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> LineHeightProperty =
+            AvaloniaProperty.Register<TextPresenter, double>(nameof(LineHeight), defaultValue: double.NaN);
+        
         /// <summary>
         /// Defines the <see cref="Background"/> property.
         /// </summary>
@@ -179,6 +185,15 @@ namespace Avalonia.Controls.Presenters
             get => GetValue(TextWrappingProperty);
             set => SetValue(TextWrappingProperty, value);
         }
+        
+        /// <summary>
+        /// Gets or sets the line height. By default, this is set to <see cref="double.NaN"/>, which determines the appropriate height automatically.
+        /// </summary>
+        public double LineHeight
+        {
+            get => GetValue(LineHeightProperty);
+            set => SetValue(LineHeightProperty, value);
+        }
 
         /// <summary>
         /// Gets or sets the text alignment.
@@ -253,7 +268,7 @@ namespace Avalonia.Controls.Presenters
             get => GetValue(CaretBrushProperty);
             set => SetValue(CaretBrushProperty, value);
         }
-
+        
         public int SelectionStart
         {
             get
@@ -281,7 +296,7 @@ namespace Avalonia.Controls.Presenters
                 SetAndRaise(SelectionEndProperty, ref _selectionEnd, value);
             }
         }
-
+        
         protected override bool BypassFlowDirectionPolicies => true;
 
         /// <summary>
@@ -301,7 +316,7 @@ namespace Avalonia.Controls.Presenters
             
             var textLayout = new TextLayout(text, typeface, FontSize, foreground, TextAlignment,
                 TextWrapping, maxWidth: maxWidth, maxHeight: maxHeight, textStyleOverrides: textStyleOverrides, 
-                flowDirection: FlowDirection);
+                flowDirection: FlowDirection, lineHeight: LineHeight);
 
             return textLayout;
         }
diff --git a/src/Avalonia.Controls/TextBox.cs b/src/Avalonia.Controls/TextBox.cs
index 45e66828c1..2d14ff0f79 100644
--- a/src/Avalonia.Controls/TextBox.cs
+++ b/src/Avalonia.Controls/TextBox.cs
@@ -79,8 +79,8 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<TextBox, int>(nameof(MaxLength), defaultValue: 0);
 
         public static readonly StyledProperty<int> MaxLinesProperty =
-      AvaloniaProperty.Register<TextBox, int>(nameof(MaxLines), defaultValue: 0);
-
+            AvaloniaProperty.Register<TextBox, int>(nameof(MaxLines), defaultValue: 0);
+        
         public static readonly DirectProperty<TextBox, string?> TextProperty =
             TextBlock.TextProperty.AddOwnerWithDataValidation<TextBox>(
                 o => o.Text,
@@ -105,6 +105,12 @@ namespace Avalonia.Controls
 
         public static readonly StyledProperty<TextWrapping> TextWrappingProperty =
             TextBlock.TextWrappingProperty.AddOwner<TextBox>();
+        
+        /// <summary>
+        /// Defines see <see cref="LineHeight"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> LineHeightProperty =
+            AvaloniaProperty.Register<TextBox, double>(nameof(LineHeight), defaultValue: double.NaN);
 
         public static readonly StyledProperty<string?> WatermarkProperty =
             AvaloniaProperty.Register<TextBox, string?>(nameof(Watermark));
@@ -358,6 +364,15 @@ namespace Avalonia.Controls
             get { return GetValue(MaxLinesProperty); }
             set { SetValue(MaxLinesProperty, value); }
         }
+        
+        /// <summary>
+        /// Gets or sets the line height. By default, this is set to <see cref="double.NaN"/>, which determines the appropriate height automatically.
+        /// </summary>
+        public double LineHeight
+        {
+            get { return GetValue(LineHeightProperty); }
+            set { SetValue(LineHeightProperty, value); }
+        }
 
         [Content]
         public string? Text
diff --git a/src/Avalonia.Themes.Default/Controls/TextBox.xaml b/src/Avalonia.Themes.Default/Controls/TextBox.xaml
index 6e3898a828..1885d3b65b 100644
--- a/src/Avalonia.Themes.Default/Controls/TextBox.xaml
+++ b/src/Avalonia.Themes.Default/Controls/TextBox.xaml
@@ -76,6 +76,7 @@
                                     SelectionEnd="{TemplateBinding SelectionEnd}"
                                     TextAlignment="{TemplateBinding TextAlignment}"
                                     TextWrapping="{TemplateBinding TextWrapping}"
+                                    LineHeight="{TemplateBinding LineHeight}"
                                     PasswordChar="{TemplateBinding PasswordChar}"
                                     RevealPassword="{TemplateBinding RevealPassword}"
                                     SelectionBrush="{TemplateBinding SelectionBrush}"
diff --git a/src/Avalonia.Themes.Fluent/Controls/TextBox.xaml b/src/Avalonia.Themes.Fluent/Controls/TextBox.xaml
index 095a2ef51f..40d9b11f7c 100644
--- a/src/Avalonia.Themes.Fluent/Controls/TextBox.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/TextBox.xaml
@@ -89,6 +89,7 @@
                                       SelectionEnd="{TemplateBinding SelectionEnd}"
                                       TextAlignment="{TemplateBinding TextAlignment}"
                                       TextWrapping="{TemplateBinding TextWrapping}"
+                                      LineHeight="{TemplateBinding LineHeight}"
                                       PasswordChar="{TemplateBinding PasswordChar}"
                                       RevealPassword="{TemplateBinding RevealPassword}"
                                       SelectionBrush="{TemplateBinding SelectionBrush}"