v3: finger touch panning/zoom + textbox auto-activates text tool

Author: Learnmore-smart

Controls/PdfPageControl.xaml

@@ -6,10 +6,18 @@
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d">
 
-    <Grid x:Name="PageGrid" Background="White">
-        <!-- PDF Background -->
-        <Image x:Name="PdfImage" Stretch="Uniform" HorizontalAlignment="Center" VerticalAlignment="Top"
-               RenderOptions.BitmapScalingMode="HighQuality"/>
+    <Grid x:Name="RootGrid">
+        <!-- Shadow casting Border (separate from content to maintain hardware accel for ink) -->
+        <Border Background="White">
+            <Border.Effect>
+                <DropShadowEffect BlurRadius="12" ShadowDepth="2" Opacity="0.10" Color="Black" />
+            </Border.Effect>
+        </Border>
+
+        <Grid x:Name="PageGrid" Background="White">
+            <!-- PDF Background -->
+            <Image x:Name="PdfImage" Stretch="Uniform" HorizontalAlignment="Center" VerticalAlignment="Top"
+                   RenderOptions.BitmapScalingMode="HighQuality"/>
 
         <!-- Ink Layer (WPF InkCanvas) -->
         <InkCanvas x:Name="InkCanvas" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="Transparent"
@@ -18,7 +26,10 @@
                    Stylus.IsFlicksEnabled="False" />
 
         <!-- Text/Widget Layer -->
-        <Canvas x:Name="TextOverlayCanvas" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="Transparent"/>
+        <Canvas x:Name="TextOverlayCanvas" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
+
+        <!-- Persistent Text Highlights Layer -->
+        <Canvas x:Name="HighlightsCanvas" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="Transparent" IsHitTestVisible="False"/>
 
         <!-- PDF Text Selection Layer -->
         <Canvas x:Name="PdfTextSelectionCanvas" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
@@ -39,6 +50,7 @@
                      Visibility="Collapsed"
                      IsHitTestVisible="False"/>
         </Canvas>
+        </Grid>
     </Grid>
 </UserControl>
 

Controls/PdfPageControl.xaml.cs

@@ -146,9 +146,16 @@ public BitmapSource PageSource
         /// </summary>
         public bool TiltEnabled { get; set; } = true;
 
+        // Custom stroke collection to prevent WPF's InkCanvas from clearing strokes
+        // during visibility or EditingMode toggles.
+        private readonly StrokeCollection _strokes = new StrokeCollection();
+
         public PdfPageControl()
         {
             InitializeComponent();
+            
+            // Assign stable stroke collection
+            InkCanvas.Strokes = _strokes;
 
             _drawingAttributes = new DrawingAttributes
             {
@@ -164,6 +171,8 @@ public PdfPageControl()
             };
 
             InkCanvas.DefaultDrawingAttributes = _drawingAttributes;
+            InkCanvas.UseCustomCursor = true;
+            InkCanvas.Cursor = Cursors.None;
             InkCanvas.EditingMode = InkCanvasEditingMode.None;
             InkCanvas.EditingModeInverted = InkCanvasEditingMode.None; // Disable native inverted erasing so we can use custom logic
             InkCanvas.StrokeCollected += InkCanvas_StrokeCollected;
@@ -178,6 +187,25 @@ public PdfPageControl()
             Unloaded += PdfPageControl_Unloaded;
         }
 
+        /// <summary>
+        /// Returns true if the given stylus device is a finger touch rather
+        /// than a pen/stylus.  Used to let finger events pass through to the
+        /// WPF manipulation system for pan/zoom gestures.
+        /// </summary>
+        private static bool IsTouchFinger(StylusDevice device)
+        {
+            if (device == null) return false;
+            var tablet = device.TabletDevice;
+            if (tablet == null) return false;
+            // Pen devices report as Stylus. Some pen-as-touch devices (e.g.
+            // Huawei M-Pencil) report as Touch but have multiple stylus buttons.
+            // Real fingers have TabletDeviceType.Touch with ≤1 button.
+            if (tablet.Type == System.Windows.Input.TabletDeviceType.Stylus)
+                return false;
+            return tablet.Type == System.Windows.Input.TabletDeviceType.Touch
+                && device.StylusButtons.Count <= 1;
+        }
+
         /// <summary>
         /// Set the shared <see cref="WindowsPenService"/> so this control can
         /// probe stylus devices and read pressure/tilt capabilities.
@@ -291,8 +319,9 @@ private void PdfPageControl_RequestBringIntoView(object sender, RequestBringInto
 
         private void InkCanvas_MouseEnter(object sender, MouseEventArgs e)
         {
-            if (_currentMode == CustomInkInputProcessingMode.Erasing || _isStylusInverted)
+            if (_currentMode == CustomInkInputProcessingMode.Erasing || _isStylusInverted || _currentMode == CustomInkInputProcessingMode.Inking)
             {
+                UpdateBrushIndicatorStyle();
                 EraserIndicator.Visibility = Visibility.Visible;
                 Cursor = Cursors.None;
                 UpdateEraserIndicatorPosition(e.GetPosition(PageGrid));
@@ -344,6 +373,12 @@ private void InkCanvas_StylusInAirMove(object sender, StylusEventArgs e)
 
             if (inverted)
             {
+                UpdateBrushIndicatorStyle();
+                UpdateEraserIndicatorPosition(e.GetPosition(PageGrid));
+            }
+            else if (_currentMode == CustomInkInputProcessingMode.Inking)
+            {
+                UpdateBrushIndicatorStyle();
                 UpdateEraserIndicatorPosition(e.GetPosition(PageGrid));
             }
         }
@@ -399,6 +434,11 @@ private void PdfTextSelectionCanvas_StylusDown(object sender, StylusDownEventArg
             if (!_isPdfTextSelectionEnabled)
                 return;
 
+            // Let finger touches pass through to WPF manipulation (pan/zoom).
+            // Only pen/stylus devices should trigger PDF text selection.
+            if (IsTouchFinger(e.StylusDevice))
+                return;
+
             PdfTextSelectionCanvas.CaptureStylus();
             PdfTextSelectionPointerPressed?.Invoke(this, new PdfTextSelectionPointerEventArgs(e.GetPosition(PageGrid), MouseButtonState.Pressed));
             e.Handled = true;
@@ -409,6 +449,9 @@ private void PdfTextSelectionCanvas_StylusMove(object sender, StylusEventArgs e)
             if (!_isPdfTextSelectionEnabled)
                 return;
 
+            if (IsTouchFinger(e.StylusDevice))
+                return;
+
             PdfTextSelectionPointerMoved?.Invoke(this, new PdfTextSelectionPointerEventArgs(e.GetPosition(PageGrid), MouseButtonState.Pressed));
             if (PdfTextSelectionCanvas.IsStylusCaptured)
                 e.Handled = true;
@@ -419,6 +462,9 @@ private void PdfTextSelectionCanvas_StylusUp(object sender, StylusEventArgs e)
             if (!_isPdfTextSelectionEnabled)
                 return;
 
+            if (IsTouchFinger(e.StylusDevice))
+                return;
+
             PdfTextSelectionPointerReleased?.Invoke(this, new PdfTextSelectionPointerEventArgs(e.GetPosition(PageGrid), MouseButtonState.Released));
             if (PdfTextSelectionCanvas.IsStylusCaptured)
                 PdfTextSelectionCanvas.ReleaseStylusCapture();
@@ -527,6 +573,7 @@ private void InkCanvas_StylusDown(object sender, StylusDownEventArgs e)
                     InkCanvas.EditingMode = InkCanvasEditingMode.None;
 
                 // Show eraser indicator at contact point
+                UpdateBrushIndicatorStyle();
                 EraserIndicator.Visibility = Visibility.Visible;
                 InkCanvas.Cursor = Cursors.None;
                 UpdateEraserIndicatorPosition(e.GetPosition(PageGrid));
@@ -575,24 +622,46 @@ private void InkCanvas_StylusUp(object sender, StylusEventArgs e)
 
         private void InkCanvas_MouseMove(object sender, MouseEventArgs e)
         {
-            if (_currentMode == CustomInkInputProcessingMode.Erasing)
+            if (_currentMode == CustomInkInputProcessingMode.Erasing || _currentMode == CustomInkInputProcessingMode.Inking)
             {
+                UpdateBrushIndicatorStyle();
                 var point = e.GetPosition(PageGrid);
                 UpdateEraserIndicatorPosition(point);
 
-                if (e.LeftButton == MouseButtonState.Pressed)
+                if (_currentMode == CustomInkInputProcessingMode.Erasing && e.LeftButton == MouseButtonState.Pressed)
                 {
                     EraseStrokesAtPoints(new StylusPointCollection { new StylusPoint(e.GetPosition(InkCanvas).X, e.GetPosition(InkCanvas).Y) });
                 }
             }
         }
 
+        private void UpdateBrushIndicatorStyle()
+        {
+            if (_currentMode == CustomInkInputProcessingMode.Erasing || _isStylusInverted)
+            {
+                EraserIndicator.Width = _eraserSize;
+                EraserIndicator.Height = _eraserSize;
+                EraserIndicator.Stroke = new SolidColorBrush(Color.FromArgb(255, 0, 120, 212));
+                EraserIndicator.Fill = new SolidColorBrush(Color.FromArgb(16, 0, 120, 212));
+            }
+            else if (_currentMode == CustomInkInputProcessingMode.Inking)
+            {
+                double size = _drawingAttributes.Width;
+                EraserIndicator.Width = Math.Max(4, size);
+                EraserIndicator.Height = Math.Max(4, size);
+                
+                Color c = _drawingAttributes.Color;
+                EraserIndicator.Stroke = new SolidColorBrush(Color.FromArgb(200, c.R, c.G, c.B));
+                EraserIndicator.Fill = _drawingAttributes.IsHighlighter ? new SolidColorBrush(Color.FromArgb(50, c.R, c.G, c.B)) : Brushes.Transparent;
+            }
+        }
+
         private void UpdateEraserIndicatorPosition(Point point)
         {
-            EraserIndicator.Width = _eraserSize;
-            EraserIndicator.Height = _eraserSize;
-            Canvas.SetLeft(EraserIndicator, point.X - _eraserSize / 2);
-            Canvas.SetTop(EraserIndicator, point.Y - _eraserSize / 2);
+            double w = EraserIndicator.Width;
+            double h = EraserIndicator.Height;
+            Canvas.SetLeft(EraserIndicator, point.X - w / 2);
+            Canvas.SetTop(EraserIndicator, point.Y - h / 2);
             EraserIndicator.Visibility = Visibility.Visible;
         }
 
@@ -717,7 +786,9 @@ private static void OnPageSourceChanged(DependencyObject d, DependencyPropertyCh
 
         public void SetMode(bool isTextMode)
         {
-            TextOverlayCanvas.IsHitTestVisible = isTextMode;
+            // Always keep TextOverlayCanvas hit-testable so textboxes can be clicked in any tool mode.
+            // Its background is transparent, so non-textbox clicks fall through to InkCanvas below.
+            TextOverlayCanvas.IsHitTestVisible = true;
         }
 
         public void SetPdfTextSelectionEnabled(bool enabled)
@@ -797,7 +868,7 @@ public void SetInputMode(CustomInkInputProcessingMode mode)
                     if (!_isPdfTextSelectionEnabled)
                         InkCanvas.IsHitTestVisible = true;
                     InkCanvas.EditingMode = InkCanvasEditingMode.Ink;
-                    EraserIndicator.Visibility = Visibility.Collapsed;
+                    // Keep indicator visible since we're updating it on mouse/stylus move now
                     InkCanvas.Cursor = Cursors.Cross;
                     Cursor = Cursors.Arrow;
                     break;
@@ -1488,6 +1559,58 @@ private void SelectionOverlayCanvas_StylusUp(object sender, StylusEventArgs e)
             SelectionOverlayCanvas_MouseLeftButtonUpCore();
             e.Handled = true;
         }
+
+        private readonly List<HighlightAnnotation> _highlights = new();
+
+        public IReadOnlyList<HighlightAnnotation> GetHighlights() => _highlights;
+
+        public void AddHighlightAnnotation(IReadOnlyList<Rect> rects, Color color)
+        {
+            var highlight = new HighlightAnnotation
+            {
+                R = color.R,
+                G = color.G,
+                B = color.B,
+                A = 120 // Semi-transparent overlay
+            };
+
+            foreach (var r in rects)
+            {
+                highlight.Rects.Add(new double[] { r.X, r.Y, r.Width, r.Height });
+            }
+
+            _highlights.Add(highlight);
+            RenderHighlightVisual(highlight);
+        }
+
+        public void AddHighlight(HighlightAnnotation highlight)
+        {
+            _highlights.Add(highlight);
+            RenderHighlightVisual(highlight);
+        }
+
+        private void RenderHighlightVisual(HighlightAnnotation highlight)
+        {
+            var color = Color.FromArgb(highlight.A, highlight.R, highlight.G, highlight.B);
+            var brush = new SolidColorBrush(color);
+
+            foreach (var rectInfo in highlight.Rects)
+            {
+                if (rectInfo.Length >= 4)
+                {
+                    var rect = new System.Windows.Shapes.Rectangle
+                    {
+                        Width = rectInfo[2],
+                        Height = rectInfo[3],
+                        Fill = brush,
+                        IsHitTestVisible = false
+                    };
+                    Canvas.SetLeft(rect, rectInfo[0]);
+                    Canvas.SetTop(rect, rectInfo[1]);
+                    HighlightsCanvas.Children.Add(rect);
+                }
+            }
+        }
     }
 }
 

MainWindow.xaml

@@ -210,7 +210,7 @@
         <Grid x:Name="TabContentArea" Grid.Row="2"/>
 
         <Border x:Name="ToastBorder" Grid.Row="2" HorizontalAlignment="Center" VerticalAlignment="Bottom"
-                Margin="0,0,0,28" Visibility="Collapsed" Opacity="0" IsHitTestVisible="False"
+                Margin="0,0,0,80" Visibility="Collapsed" Opacity="0" IsHitTestVisible="False"
                 CornerRadius="10" Padding="20,10">
             <Border.Background>
                 <SolidColorBrush Color="#1A1A1A" Opacity="0.88"/>

Models/AnnotationModels.cs

@@ -12,6 +12,7 @@ public class PageAnnotation
     {
         public List<StrokeAnnotation> Strokes { get; set; } = new();
         public List<TextAnnotation> Texts { get; set; } = new();
+        public List<HighlightAnnotation> Highlights { get; set; } = new();
     }
 
     public class StrokeAnnotation
@@ -35,4 +36,14 @@ public class TextAnnotation
         public byte B { get; set; }
         public double FontSize { get; set; } = 18;
     }
+
+    public class HighlightAnnotation
+    {
+        // Each array contains [X, Y, Width, Height]
+        public List<double[]> Rects { get; set; } = new();
+        public byte R { get; set; } = 255;
+        public byte G { get; set; } = 255;
+        public byte B { get; set; } = 0;
+        public byte A { get; set; } = 128;
+    }
 }

Models/AppSettings.cs

@@ -3,6 +3,7 @@ namespace Caelum.Models
     public sealed class AppSettings
     {
         public AppLanguage Language { get; set; } = AppLanguage.English;
+        public bool EnablePressure { get; set; } = true;
     }
 
     public sealed class LanguageOption

Pages/EditorPage.xaml

@@ -5,7 +5,8 @@
       Background="Transparent"
       AllowDrop="True"
       PreviewMouseDown="EditorPage_PreviewMouseDown"
-      PreviewStylusDown="EditorPage_PreviewStylusDown">
+      PreviewStylusDown="EditorPage_PreviewStylusDown"
+      PreviewKeyDown="EditorPage_PreviewKeyDown">
 
     <Page.Resources>
         <!-- Toolbar button -->
@@ -84,7 +85,7 @@
 
         <!-- PDF Pages Container (full area) -->
         <ScrollViewer x:Name="PdfScrollViewer" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto"
-                      Background="#FFB0B0B0"
+                      Background="#90E5E7EB"
                       Style="{StaticResource SleekScrollViewer}"
                       PanningMode="None"
                       Stylus.IsFlicksEnabled="False"
@@ -146,10 +147,12 @@
                 <!-- Highlighter -->
                 <ToggleButton x:Name="HighlighterToolButton" Click="HighlighterToolButton_Click"
                         Style="{StaticResource ToolbarToggleButtonStyle}"
-                        Width="42" Height="36" Margin="2,0">
+                        Width="42" Height="36" Margin="2,0" ToolTip="Freehand Highlighter">
                     <TextBlock x:Name="HighlighterIcon" Text="&#xE7E6;" FontFamily="Segoe MDL2 Assets" FontSize="19" Foreground="#F59E0B"/>
                 </ToggleButton>
 
+
+
                 <!-- Eraser -->
                 <ToggleButton x:Name="EraserToolButton" Click="EraserToolButton_Click"
                         Style="{StaticResource ToolbarToggleButtonStyle}"
@@ -173,8 +176,7 @@
                     <TextBlock Text="A" FontSize="17" FontWeight="Bold" Foreground="#555"/>
                 </ToggleButton>
 
-                <!-- Separator -->
-                <Border Width="1" Background="#18000000" Margin="4,8"/>
+
 
                 <!-- Save -->
                 <Button x:Name="SavePdfButton" Click="SavePdf_Click"
@@ -186,6 +188,13 @@
                 <!-- Separator -->
                 <Border Width="1" Background="#18000000" Margin="4,8"/>
 
+                <!-- Page Number -->
+                <TextBlock x:Name="PageNumberText" Text="0 / 0" FontSize="13" Foreground="#555" 
+                           VerticalAlignment="Center" Margin="8,0,8,0" ToolTip="Current Page"/>
+
+                <!-- Separator -->
+                <Border Width="1" Background="#18000000" Margin="4,8"/>
+
                 <!-- Zoom Out -->
                 <Button x:Name="ZoomOutButton" Click="ZoomOutButton_Click"
                         Style="{StaticResource ToolbarButtonStyle}"