code reorg

src/PostIt/PostIt/Views/Signature/SignaturePage.axaml.cs

@@ -0,0 +1,120 @@
+using System;
+using System.Collections.Generic;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Shapes;
+using Avalonia.Media;
+using PostIt.Controls;
+using PostIt.ViewModels;
+
+namespace PostIt.Views;
+
+public partial class SignaturePage : ContentPage
+{
+    private static readonly IBrush StrokeBrush = new SolidColorBrush(Color.FromRgb(0x10, 0x10, 0x10));
+    private const double StrokeThickness = 2.0;
+    private const double CoordinateMax = 10_000.0;
+
+    private SignaturePageViewModel? _vm;
+    private SignaturePadControl? _control;
+
+    public SignaturePage()
+    {
+        InitializeComponent();
+
+        // Wire the capture area: the Pad itself is the control, the
+        // surrounding Border (PadFrame) is the hit-test region. We
+        // set CaptureArea once the control's template has been
+        // applied — for an inline control with no template, that
+        // happens on first measure, which is guaranteed before
+        // the user can interact, so attaching here is safe.
+        _control = Pad;
+        _control.CaptureArea = PadFrame;
+
+        DataContextChanged += (_, _) => RebindViewModel(DataContext as SignaturePageViewModel);
+    }
+
+    private void RebindViewModel(SignaturePageViewModel? vm)
+    {
+        if (_vm is not null)
+        {
+            _vm.Detach();
+            _control!.RedrawRequested -= OnRedrawRequested;
+        }
+
+        _vm = vm;
+
+        if (_vm is null || _control is null) return;
+
+        _vm.Attach(_control);
+        _control.RedrawRequested += OnRedrawRequested;
+        Repaint();
+    }
+
+    private void OnRedrawRequested(object? sender, EventArgs e) => Repaint();
+
+    private void Repaint()
+    {
+        if (_control is null || InkLayer is null) return;
+
+        InkLayer.Children.Clear();
+        var w = PadFrame.Bounds.Width;
+        var h = PadFrame.Bounds.Height;
+        if (w <= 0 || h <= 0) return;
+
+        var pending = _control.PendingStroke;
+        var strokes = _control.Strokes;
+        int sealedCount = strokes.Count - pending.Count;
+        if (sealedCount < 0)
+        {
+            sealedCount = 0;
+        }
+
+        int i = 0;
+        while (i < sealedCount)
+        {
+            int k = strokes[i];
+            if (k <= 0) break;
+            i++; // skip the length prefix
+
+            var poly = new Polyline
+            {
+                Stroke = StrokeBrush,
+                StrokeThickness = StrokeThickness,
+                StrokeLineCap = PenLineCap.Round,
+                StrokeJoin = PenLineJoin.Round,
+            };
+            var pts = new List<Point>(k);
+            for (int p = 0; p < k; p++)
+            {
+                int nx = strokes[i++];
+                int ny = strokes[i++];
+                pts.Add(new Point(nx / CoordinateMax * w, ny / CoordinateMax * h));
+            }
+            poly.Points = pts;
+            InkLayer.Children.Add(poly);
+        }
+
+        if (pending.Count > 0)
+        {
+            var poly = new Polyline
+            {
+                Stroke = StrokeBrush,
+                StrokeThickness = StrokeThickness,
+                StrokeLineCap = PenLineCap.Round,
+                StrokeJoin = PenLineJoin.Round,
+            };
+
+            var pts = new List<Point>(pending.Count / 2);
+            for (int p = 0; p < pending.Count; p += 2)
+            {
+                int nx = pending[p];
+                int ny = pending[p + 1];
+                pts.Add(new Point(nx / CoordinateMax * w, ny / CoordinateMax * h));
+            }
+
+            poly.Points = pts;
+            InkLayer.Children.Add(poly);
+        }
+    }
+}