| 1 | #nullable enable |
| 2 | |
| 3 | using Avalonia; |
| 4 | using Avalonia.Controls; |
| 5 | using Avalonia.Controls.Primitives; |
| 6 | using Avalonia.Threading; |
| 7 | |
| 8 | namespace CascadeIDE.Services.MarkdownPreview; |
| 9 | |
| 10 | /// <summary>Fragment ids и line hints для scroll в preview.</summary> |
| 11 | public sealed class MarkdownPreviewAnchorRegistry |
| 12 | { |
| 13 | private readonly Dictionary<string, Control> _fragments = new(StringComparer.OrdinalIgnoreCase); |
| 14 | private readonly List<(int Line, Control Control)> _lineAnchors = new(); |
| 15 | |
| 16 | public ScrollViewer? ScrollHost { get; set; } |
| 17 | |
| 18 | public void RegisterFragment(string id, Control control) |
| 19 | { |
| 20 | if (string.IsNullOrWhiteSpace(id)) |
| 21 | return; |
| 22 | |
| 23 | _fragments[id.Trim()] = control; |
| 24 | } |
| 25 | |
| 26 | public void RegisterLine(int line, Control control) |
| 27 | { |
| 28 | if (line < 1) |
| 29 | return; |
| 30 | |
| 31 | _lineAnchors.Add((line, control)); |
| 32 | } |
| 33 | |
| 34 | public void ScrollToFragment(string fragmentId) |
| 35 | { |
| 36 | if (string.IsNullOrWhiteSpace(fragmentId)) |
| 37 | return; |
| 38 | |
| 39 | if (!_fragments.TryGetValue(fragmentId.Trim(), out var control)) |
| 40 | return; |
| 41 | |
| 42 | ScrollToControl(control); |
| 43 | } |
| 44 | |
| 45 | public void ScrollToLine(int line) |
| 46 | { |
| 47 | if (line < 1 || _lineAnchors.Count == 0) |
| 48 | return; |
| 49 | |
| 50 | Control? best = null; |
| 51 | var bestDelta = int.MaxValue; |
| 52 | foreach (var (anchorLine, control) in _lineAnchors) |
| 53 | { |
| 54 | var delta = Math.Abs(anchorLine - line); |
| 55 | if (delta >= bestDelta) |
| 56 | continue; |
| 57 | |
| 58 | bestDelta = delta; |
| 59 | best = control; |
| 60 | if (delta == 0) |
| 61 | break; |
| 62 | } |
| 63 | |
| 64 | if (best is not null) |
| 65 | ScrollToControl(best); |
| 66 | } |
| 67 | |
| 68 | private void ScrollToControl(Control target) |
| 69 | { |
| 70 | if (ScrollHost?.Content is not Control content) |
| 71 | return; |
| 72 | |
| 73 | Dispatcher.UIThread.Post(() => |
| 74 | { |
| 75 | var point = target.TranslatePoint(new Point(0, 0), content); |
| 76 | if (point is null) |
| 77 | return; |
| 78 | |
| 79 | ScrollHost.Offset = new Vector( |
| 80 | ScrollHost.Offset.X, |
| 81 | Math.Max(0, point.Value.Y - 16)); |
| 82 | }, DispatcherPriority.Loaded); |
| 83 | } |
| 84 | } |
| 85 | |