14ea938c7f
Root cause of the "grid escapes the window when scrolled" bug: UiElement. DrawSelfAndChildren runs ApplyAnchor on every child AFTER OnDraw, which captured each cell's scroll-0 position and reset Top to it every frame, fighting LayoutCells' scroll offset. Cells are laid out procedurally by the list, so they must be exempt — AddItem now sets cell.Anchors = None, making LayoutCells the sole authority. Regression test reproduces the anchor-pass interaction (the unit tests missed it by calling LayoutCells in isolation, never the draw traversal). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
83 lines
3.5 KiB
C#
83 lines
3.5 KiB
C#
using AcDream.App.UI;
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using Xunit;
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namespace AcDream.App.Tests.UI;
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public sealed class UiItemListScrollTests
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{
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private static UiItemList Grid(int items)
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{
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var list = new UiItemList { Columns = 6, CellWidth = 32, CellHeight = 32, Width = 192, Height = 96 };
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list.Flush(); // drop the default single cell
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for (int i = 0; i < items; i++) list.AddItem(new UiItemSlot());
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list.LayoutCells(); // drive the scroll model + position cells
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return list;
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}
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[Fact]
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public void RowCount_ceils_to_whole_rows()
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{
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Assert.Equal(0, UiItemList.RowCount(0, 6));
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Assert.Equal(1, UiItemList.RowCount(1, 6));
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Assert.Equal(7, UiItemList.RowCount(41, 6));
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}
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[Fact]
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public void Grid_drives_scroll_model_from_content()
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{
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var list = Grid(30); // 5 rows × 32 = 160 content, 96 view
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Assert.Equal(160, list.Scroll.ContentHeight);
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Assert.Equal(96, list.Scroll.ViewHeight);
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Assert.Equal(64, list.Scroll.MaxScroll);
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Assert.True(list.Scroll.HasOverflow);
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}
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[Fact]
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public void At_top_first_three_rows_visible_rest_clipped()
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{
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var list = Grid(30);
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Assert.True(list.GetItem(0)!.Visible); // row 0, top 0
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Assert.True(list.GetItem(12)!.Visible); // row 2, top 64 (+32 == 96)
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Assert.False(list.GetItem(18)!.Visible); // row 3, top 96 (off the bottom)
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}
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[Fact]
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public void Scrolled_one_row_shifts_window_and_clips_top_row()
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{
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var list = Grid(30);
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list.Scroll.SetScrollY(32);
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list.LayoutCells();
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Assert.False(list.GetItem(0)!.Visible); // row 0 scrolled above
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Assert.Equal(0f, list.GetItem(6)!.Top); // row 1 now at the view top
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Assert.True(list.GetItem(18)!.Visible); // row 3 now visible
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}
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[Fact]
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public void Scroll_survives_the_per_frame_anchor_pass()
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{
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// Regression (the escaping-grid bug): UiElement.DrawSelfAndChildren runs ApplyAnchor
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// on every child AFTER OnDraw/LayoutCells. Grid cells must be exempt (Anchors=None) so
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// the anchor pass can't reset the scroll offset LayoutCells applied — otherwise the
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// grid translates out of the view when scrolled.
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var list = Grid(30); // cells added (Anchors=None) + laid out
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for (int i = 0; i < list.GetNumUIItems(); i++) // first anchor pass (would capture base)
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list.GetItem(i)!.ApplyAnchor(list.Width, list.Height);
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list.Scroll.SetScrollY(32); // scroll one row
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list.LayoutCells();
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for (int i = 0; i < list.GetNumUIItems(); i++) // second anchor pass (the draw traversal)
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list.GetItem(i)!.ApplyAnchor(list.Width, list.Height);
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Assert.Equal(0f, list.GetItem(6)!.Top); // row 1 stays at the view top
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Assert.False(list.GetItem(0)!.Visible); // row 0 stays clipped above
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}
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[Fact]
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public void Wheel_down_scrolls_toward_the_bottom()
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{
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var list = Grid(30); // max scroll 64, LineHeight 32
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// Silk wheel +Y = up/older; UiText negates Data0. Wheel DOWN (Data0 < 0) → +ScrollY.
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var e = new UiEvent(0u, null, UiEventType.Scroll, Data0: -1);
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bool handled = list.OnEvent(e);
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Assert.True(handled);
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Assert.Equal(32, list.Scroll.ScrollY); // one line (32px) down
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}
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}
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