Feature: Added a Range selection mode by aspect ratio value.

demo/Ursa.Demo/Pages/AspectRatioLayoutDemo.axaml

@@ -8,12 +8,18 @@
     <Grid
         RowDefinitions="Auto,*">
         <StackPanel
-            Grid.Row="0"
+            Grid.Row="0">
-            Orientation="Horizontal">
+            <u:NumericDoubleUpDown InnerLeftContent="AspectRatioChangeAmbiguity"
-            <u:NumericDoubleUpDown InnerLeftContent="AspectRatioChangeAmbiguity" Value="{Binding  #AspectRatioLayout.AspectRatioChangeAmbiguity}"></u:NumericDoubleUpDown>
+                                   Value="{Binding  #AspectRatioLayout.AspectRatioChangeAmbiguity}">
+            </u:NumericDoubleUpDown>
+            <TextBlock Text="{Binding #AspectRatioLayout.AspectRatioValue,StringFormat='AspectRatioValue: {0}'}"></TextBlock>
         </StackPanel>
 
-        <u:AspectRatioLayout Name="AspectRatioLayout" Grid.Row="1">
+        <u:AspectRatioLayout Name="AspectRatioLayout" Grid.Row="1"
+                             BorderThickness="1"
+                             BorderBrush="Red"
+                             Margin="2"
+                             CornerRadius="10">
             <u:AspectRatioLayoutItem AcceptAspectRatioMode="HorizontalRectangle">
                 <Button>HorizontalRectangle ControlLayout</Button>
             </u:AspectRatioLayoutItem>
@@ -23,6 +29,51 @@
             <u:AspectRatioLayoutItem AcceptAspectRatioMode="Square">
                 <Button>Square ControlLayout</Button>
             </u:AspectRatioLayoutItem>
+            <u:AspectRatioLayoutItem StartAspectRatioValue="2" EndAspectRatioValue="2.2">
+                <TextBlock
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center">
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].StartAspectRatioValue,StringFormat='StartAspectRatioValue {0}'}"></Run>
+                    <LineBreak></LineBreak>
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].EndAspectRatioValue,StringFormat='EndAspectRatioValue {0}'}"></Run>
+                </TextBlock>
+            </u:AspectRatioLayoutItem>
+            <u:AspectRatioLayoutItem StartAspectRatioValue="2" EndAspectRatioValue="2.4">
+                <TextBlock
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center">
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].StartAspectRatioValue,StringFormat='StartAspectRatioValue {0}'}"></Run>
+                    <LineBreak></LineBreak>
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].EndAspectRatioValue,StringFormat='EndAspectRatioValue {0}'}"></Run>
+                </TextBlock>
+            </u:AspectRatioLayoutItem> 
+            <u:AspectRatioLayoutItem StartAspectRatioValue="2" EndAspectRatioValue="2.6">
+                <TextBlock
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center">
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].StartAspectRatioValue,StringFormat='StartAspectRatioValue {0}'}"></Run>
+                    <LineBreak></LineBreak>
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].EndAspectRatioValue,StringFormat='EndAspectRatioValue {0}'}"></Run>
+                </TextBlock>
+            </u:AspectRatioLayoutItem> 
+            <u:AspectRatioLayoutItem StartAspectRatioValue="2" EndAspectRatioValue="2.8">
+                <TextBlock
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center">
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].StartAspectRatioValue,StringFormat='StartAspectRatioValue {0}'}"></Run>
+                    <LineBreak></LineBreak>
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].EndAspectRatioValue,StringFormat='EndAspectRatioValue {0}'}"></Run>
+                </TextBlock>
+            </u:AspectRatioLayoutItem> 
+            <u:AspectRatioLayoutItem StartAspectRatioValue="1.3" EndAspectRatioValue="1.5">
+                <TextBlock
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center">
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].StartAspectRatioValue,StringFormat='StartAspectRatioValue {0}'}"></Run>
+                    <LineBreak></LineBreak>
+                    <Run Text="{Binding $parent[u:AspectRatioLayoutItem].EndAspectRatioValue,StringFormat='EndAspectRatioValue {0}'}"></Run>
+                </TextBlock>
+            </u:AspectRatioLayoutItem>
         </u:AspectRatioLayout>
     </Grid>
 </UserControl>

src/Ursa/Controls/AspectRatioLayout/AspectRatioLayout.cs

@@ -45,6 +45,16 @@ public class AspectRatioLayout : TransitioningContentControl
         set => SetValue(CurrentAspectRatioModeProperty, value);
     }
 
+    public static readonly StyledProperty<double> AspectRatioValueProperty =
+        AvaloniaProperty.Register<AspectRatioLayout, double>(
+            nameof(AspectRatioValue));
+
+    public double AspectRatioValue
+    {
+        get => GetValue(AspectRatioValueProperty);
+        set => SetValue(AspectRatioValueProperty, value);
+    }
+
     protected override Type StyleKeyOverride => typeof(TransitioningContentControl);
 
     [Content]
@@ -73,9 +83,14 @@ public class AspectRatioLayout : TransitioningContentControl
         return _history.All(x => x) || _history.All(x => !x);
     }
 
+    private double GetAspectRatio(Rect rect)
+    {
+        return Math.Round(Math.Truncate(Math.Abs(rect.Width)) / Math.Truncate(Math.Abs(rect.Height)), 3);
+    }
+
     private AspectRatioMode GetScaleMode(Rect rect)
     {
-        var scale = Math.Round(Math.Truncate(Math.Abs(rect.Width)) / Math.Truncate(Math.Abs(rect.Height)), 3);
+        var scale = GetAspectRatio(rect);
         var absA = Math.Abs(AspectRatioChangeAmbiguity);
         var h = 1d + absA;
         var v = 1d - absA;
@@ -96,12 +111,20 @@ public class AspectRatioLayout : TransitioningContentControl
             {
                 var o = (Rect)change.OldValue!;
                 var n = (Rect)change.NewValue!;
-                UpdataHistory(GetScaleMode(o) == GetScaleMode(n));
+                UpdataHistory(GetAspectRatio(o) <= GetAspectRatio(n));
                 if (!IsRightChanges()) return;
                 CurrentAspectRatioMode = GetScaleMode(n);
             }
 
-            var c = Items.FirstOrDefault(x => x.AcceptAspectRatioMode == GetScaleMode(Bounds));
+            AspectRatioValue = GetAspectRatio(Bounds);
+            var c =
+                Items
+                    .Where(x => x.IsUseAspectRatioRange)
+                    .FirstOrDefault(x =>
+                        x.StartAspectRatioValue <= AspectRatioValue
+                        && AspectRatioValue <= x.EndAspectRatioValue);
+
+            c ??= Items.FirstOrDefault(x => x.AcceptAspectRatioMode == GetScaleMode(Bounds));
             if (c == null)
             {
                 if (Items.Count == 0) return;

src/Ursa/Controls/AspectRatioLayout/AspectRatioLayoutItem.cs

@@ -9,9 +9,62 @@ public class AspectRatioLayoutItem : ContentControl
         AvaloniaProperty.Register<AspectRatioLayoutItem, AspectRatioMode>(
             nameof(AcceptAspectRatioMode));
 
+    public static readonly StyledProperty<double> StartAspectRatioValueProperty =
+        AvaloniaProperty.Register<AspectRatioLayoutItem, double>(
+            nameof(StartAspectRatioValue), defaultValue: double.NaN);
+
+    public double StartAspectRatioValue
+    {
+        get => GetValue(StartAspectRatioValueProperty);
+        set => SetValue(StartAspectRatioValueProperty, value);
+    }
+
+    public static readonly StyledProperty<double> EndAspectRatioValueProperty =
+        AvaloniaProperty.Register<AspectRatioLayoutItem, double>(
+            nameof(EndAspectRatioValue), defaultValue: double.NaN);
+
+    public double EndAspectRatioValue
+    {
+        get => GetValue(EndAspectRatioValueProperty);
+        set => SetValue(EndAspectRatioValueProperty, value);
+    }
+
+
+    private bool _isUseAspectRatioRange;
+
+    public static readonly DirectProperty<AspectRatioLayoutItem, bool> IsUseAspectRatioRangeProperty =
+        AvaloniaProperty.RegisterDirect<AspectRatioLayoutItem, bool>(
+            nameof(IsUseAspectRatioRange), o => o.IsUseAspectRatioRange);
+
+    public bool IsUseAspectRatioRange
+    {
+        get => _isUseAspectRatioRange;
+        private set => SetAndRaise(IsUseAspectRatioRangeProperty, ref _isUseAspectRatioRange, value);
+    }
+
     public AspectRatioMode AcceptAspectRatioMode
     {
         get => GetValue(AcceptScaleModeProperty);
         set => SetValue(AcceptScaleModeProperty, value);
     }
+
+    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+    {
+        base.OnPropertyChanged(change);
+        if (change.Property == StartAspectRatioValueProperty ||
+            change.Property == EndAspectRatioValueProperty)
+        {
+            UpdataIsUseAspectRatioRange();
+        }
+    }
+
+    private void UpdataIsUseAspectRatioRange()
+    {
+        if (double.IsNaN(StartAspectRatioValue)
+            || double.IsNaN(EndAspectRatioValue)
+            || StartAspectRatioValue > EndAspectRatioValue)
+            IsUseAspectRatioRange = false;
+        else
+            IsUseAspectRatioRange = true;
+    }
 }