enhance: auto hide scrollbar in hex-viewer

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Views/BinaryFileViewer.axaml

@@ -74,7 +74,10 @@
       <ContentControl x:Name="ContentPanel" Margin="8,4,0,4" Content="{Binding Content, Mode=OneWay}">
         <ContentControl.DataTemplates>
           <DataTemplate DataType="m:BinaryFile">
-            <Grid ColumnDefinitions="*,Auto" Background="Transparent" PointerWheelChanged="OnContentPointerWheelChanged">
+            <Grid ColumnDefinitions="*,Auto"
+                  Background="Transparent"
+                  PointerWheelChanged="OnContentPointerWheelChanged"
+                  SizeChanged="OnContentSizeChanged">
               <v:HexViewer Grid.Column="0"
                            Foreground="{DynamicResource Brush.FG1}"
                            HeaderForeground="{DynamicResource Brush.Accent}"
@@ -85,8 +88,7 @@
                          Orientation="Vertical"
                          AllowAutoHide="False"
                          SmallChange="18"
-                         ValueChanged="OnScrollBarValueChanged"
-                         SizeChanged="OnScrollBarSizeChanged"/>
+                         ValueChanged="OnScrollBarValueChanged"/>
             </Grid>
           </DataTemplate>
         </ContentControl.DataTemplates>

src/Views/BinaryFileViewer.axaml.cs

@@ -332,31 +332,43 @@ private void OnContentPointerWheelChanged(object sender, PointerWheelEventArgs e
                 return;
 
             var scroller = grid.FindDescendantOfType<ScrollBar>();
-            if (scroller == null)
+            if (scroller == null || !scroller.IsVisible)
                 return;
 
             scroller.Value -= e.Delta.Y * HexViewer.LINE_HEIGHT;
         }
 
-        private void OnScrollBarValueChanged(object sender, RangeBaseValueChangedEventArgs e)
+        private void OnContentSizeChanged(object sender, SizeChangedEventArgs e)
         {
-            if (sender is ScrollBar scroller)
+            if (sender is not Grid { DataContext: Models.BinaryFile file } grid)
+                return;
+
+            var scroller = grid.FindDescendantOfType<ScrollBar>();
+            if (scroller == null)
+                return;
+
+            var viewport = grid.Bounds.Height - HexViewer.HEADER_HEIGHT;
+            var max = Math.Ceiling(file.Size * 1.0 / HexViewer.BYTES_PER_LINE) * HexViewer.LINE_HEIGHT - viewport;
+
+            if (max <= 0)
             {
-                var viewer = this.FindDescendantOfType<HexViewer>();
-                if (viewer != null)
-                    viewer.Offset = (long)(Math.Ceiling(scroller.Value / HexViewer.LINE_HEIGHT) * HexViewer.BYTES_PER_LINE);
+                scroller.IsVisible = false;
+            }
+            else
+            {
+                scroller.IsVisible = true;
+                scroller.ViewportSize = viewport;
+                scroller.Maximum = max;
             }
         }
 
-        private void OnScrollBarSizeChanged(object sender, SizeChangedEventArgs e)
+        private void OnScrollBarValueChanged(object sender, RangeBaseValueChangedEventArgs e)
         {
-            if (sender is ScrollBar { DataContext: Models.BinaryFile file } scroller)
+            if (sender is ScrollBar scroller)
             {
-                var viewport = scroller.Bounds.Height;
-                var max = Math.Ceiling(file.Size / (double)HexViewer.BYTES_PER_LINE) * HexViewer.LINE_HEIGHT - viewport;
-
-                scroller.ViewportSize = viewport;
-                scroller.Maximum = Math.Max(viewport, max);
+                var viewer = this.FindDescendantOfType<HexViewer>();
+                if (viewer != null)
+                    viewer.Offset = (long)(Math.Ceiling(scroller.Value / HexViewer.LINE_HEIGHT) * HexViewer.BYTES_PER_LINE);
             }
         }
 
@@ -383,11 +395,11 @@ private void OnGotoAddressTextChanged(object sender, TextChangedEventArgs e)
                     return;
 
                 var scroller = ContentPanel.FindDescendantOfType<ScrollBar>();
-                if (scroller == null)
-                    return;
-
-                var offset = Math.Floor(idx / (double)HexViewer.BYTES_PER_LINE) * HexViewer.LINE_HEIGHT - (scroller.ViewportSize * 0.5);
-                scroller.Value = Math.Max(0, offset);
+                if (scroller is { IsVisible: true })
+                {
+                    var offset = Math.Floor(idx * 1.0 / HexViewer.BYTES_PER_LINE) * HexViewer.LINE_HEIGHT - (scroller.ViewportSize * 0.5);
+                    scroller.Value = Math.Max(0, offset);
+                }
 
                 var viewer = this.FindDescendantOfType<HexViewer>(false);
                 viewer?.SetHighlightedIndex(idx);

src/Views/DiffView.axaml

@@ -252,7 +252,7 @@
                       HorizontalAlignment="Center"
                       Content="{DynamicResource Text.Diff.Binary.ViewContentOfNew}"
                       IsVisible="{Binding NewSize, Mode=OneWay, Converter={x:Static c:LongConverters.IsGreaterThanZero}}"
-                      Click="OnOpenStandaloneHexEditor"/>
+                      Click="OnOpenBinaryFileViewer"/>
             </StackPanel>
           </DataTemplate>
 

src/Views/DiffView.axaml.cs

@@ -85,7 +85,7 @@ private void OnOpenSubmoduleRevisionCompare(object sender, RoutedEventArgs e)
             }
         }
 
-        private async void OnOpenStandaloneHexEditor(object sender, RoutedEventArgs e)
+        private async void OnOpenBinaryFileViewer(object sender, RoutedEventArgs e)
         {
             if (sender is Button { DataContext: Models.BinaryDiff diff } && diff.NewSize > 0)
             {