Add event timeline histogram with zoom, scope lens, and group-by

[jschick04]

Summary

Adds an event-timeline histogram to the log-table view (ADO 62704677): a compact, toggleable strip above the table that plots event volume over time with WPA-style continuous zoom and horizontal pan, a scope lens that drills the table into a time range, and group-by dimensions (severity / source / event id / task category / opcode / log). Toggle it from View > Timeline; its visibility persists across launches (default on).

What's included

• WPA-style navigation: cursor-anchored wheel zoom, shift-wheel / scrollbar pan, + / - / Fit toolbar buttons, and keyboard arrows / + / - / Home. The default view fits the whole survivor span; zooming narrows the window and reveals a thin horizontal scrollbar that matches the app.
• Scope lens (drill-down): Enter (when focused) or the Scope button narrows the log table to the visible time window through the existing filter-lens stack (ShowTimeRange); double-click resets. Zoom is visual navigation, Scope is the explicit filter action (kept distinct and visually cued).
• Undo zoom: a window-history stack with a toolbar Undo button and right-click; keyboard Enter always scopes.
• Group-by dimensions: severity (stacked Error / Warning / Normal bands) plus source / event id / task category / opcode / log, rendered as N stacked bands with an Okabe-Ito palette, forced-colors hatching, and clickable legend toggles.
• Find-hit markers: while in-view Find (Ctrl+F) is active, its matches are drawn as triangles on the histogram's top track (binary-searched per render bin).
• Accessibility: the timeline is a focusable role=region (roledescription=Timeline) whose aria-label summarizes the entire loaded view (total events, overall time range, group breakdown); pan/zoom updates a debounced visually-hidden aria-live=polite status with the current window's count / range / breakdown, and keyboard bin-cursor navigation announces the focused bin via a visually-hidden aria-live=assertive region. aria-keyshortcuts advertises the commands, and the decorative plot SVG is role=presentation.

Implementation notes

• Eventing scans survivor-scoped time ticks into per-severity / per-field / per-event-id bucket counts (sealed chunks plus the pending tail, cancellable per chunk) behind the IEventColumnReader seam.
• Runtime exposes polymorphic IEventColumnView bucketing (single-log views delegate; the combined view aggregates children) and a pure client-side HistogramAggregator that folds base bins into viewport-width render bins with sqrt-scaled stacked-band geometry (1px floor, largest-remainder distribution).
• The base scan runs on a background, epoch-gated, single-flight path marshalled back to the renderer with InvokeAsync, and a per-session token prevents a disposed pane's in-flight interop from clobbering a re-initialized one.
• The window is tracked in absolute ticks and is always bin-aligned: follow-latest by default, pinned while zoomed, and re-anchored on live-tail.
• The Log dimension labels each band by owning-log short name, escalating to a disambiguated short (parent) or full path only when short names collide.

Validation

• Test suites green across Eventing / Runtime / UI; touched projects build 0 warnings / 0 errors.
• Governance: pre-implementation and post-code multi-model panels were unanimous during development; a final full-slate panel over the committed diff ran multiple rounds to unanimous convergence, finding and fixing defects including scroll-drift at high bucket resolution, no-op zooms poisoning the undo stack, edge drags bypassing the min-drag threshold, a disjoint reload retaining stale undo history, a tab-switch stale render plus a one-member group, an undo-vs-queued-navigation race resolved with a generation token, culture-invariant event-id keys, a time-zone announcement refresh, and an extreme-zoom track cap.

Manual acceptance (WebView2)

Visual and interaction outcomes automated tests can't verify:

• Toggle from View > Timeline; visibility persists across relaunch.
• Wheel zoom (cursor-anchored), shift-wheel / scrollbar pan, + / - / Fit, keyboard navigation; Undo (button and right-click); double-click reset.
• Scope narrows the table to the window and the scoped state is visually cued.
• Group-by across severity / source / event id / task category / opcode / log; legend toggles; light / dark / forced-colors.
• Find-hit markers stay aligned with matches while Find is active.

[Copilot]

Pull request overview

Adds a timeline histogram feature to the log table view, including rendering/interaction (zoom/pan/scope), persisted visibility, group-by dimensions, and “Find hit” markers driven by the Find subsystem.

Changes:

• Introduces a new HistogramPane UI component (Razor/CSS/JS interop) with navigation, scoping into ShowTimeRange, group-by legend, and marker overlays.
• Adds runtime/eventing support for building and aggregating histograms (bucketing by severity/field/event-id, downsampling, anomaly flagging) plus persisted “Timeline visible” state.
• Expands test coverage across UI, runtime, and eventing layers for histogram primitives, scaling, summary strings, and Find marker publishing/clearing.

Reviewed changes

Copilot reviewed 58 out of 58 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/Unit/EventLogExpert.UI.Tests/TestUtils/LogTablePaneDependenciesExtensions.cs	Registers IFindMarkerSource in UI test DI.
tests/Unit/EventLogExpert.UI.Tests/Menu/MenuBarGroupingTests.cs	Adds histogram visibility state selection to menu tests.
tests/Unit/EventLogExpert.UI.Tests/LogTable/LogTablePaneFindTests.cs	Verifies Find publishes/clears marker ticks via IFindMarkerSource.
tests/Unit/EventLogExpert.UI.Tests/LogTable/FindMarkerSourceTests.cs	Unit tests for FindMarkerSource publish/clear behavior.
tests/Unit/EventLogExpert.UI.Tests/Layout/MainContentTests.cs	Verifies histogram pane renders conditionally on visibility state.
tests/Unit/EventLogExpert.Runtime.Tests/LogTable/TestSupport/LegacyEventColumnView.cs	Extends legacy test view with histogram/time-tick APIs.
tests/Unit/EventLogExpert.Runtime.Tests/Histogram/HistogramSummaryTests.cs	Tests accessible summary/announcement string generation.
tests/Unit/EventLogExpert.Runtime.Tests/Histogram/HistogramScaleTests.cs	Tests sqrt scaling + stacked pixel allocation behavior.
tests/Unit/EventLogExpert.Runtime.Tests/Histogram/HistogramGroupsTests.cs	Tests group key stability/uniqueness semantics.
tests/Unit/EventLogExpert.Runtime.Tests/Histogram/HistogramBuilderTests.cs	Tests histogram scan/build across dimensions and combined views.
tests/Unit/EventLogExpert.Runtime.Tests/Histogram/HistogramAggregatorTests.cs	Tests downsampling, window snapping, anomalies, and totals.
tests/Unit/EventLogExpert.Runtime.Tests/FilterLenses/FilterLensCommandsTests.cs	Adds tests for ShowTimeRange and label conversion edge case.
tests/Unit/EventLogExpert.Eventing.Tests/Common/Events/TimeTicksHistogramTests.cs	Validates eventing bucketing/counting/tick-range primitives.
tests/Shared/EventLogExpert.Eventing.TestUtils/Common/Events/LegacyEventColumnReader.cs	Implements histogram-related reader APIs for shared tests.
src/EventLogExpert/DependencyInjection/MauiProgramExtensions.cs	Registers histogram preferences provider for Maui app.
src/EventLogExpert/Adapters/Settings/HistogramPreferencesAdapter.cs	Implements persisted “histogram visible” preference using Preferences.
src/EventLogExpert/Adapters/Menu/MauiMenuActionService.cs	Wires menu action to histogram visibility command.
src/EventLogExpert.UI/Menu/MenuBar.razor.cs	Adds View > Timeline toggle bound to HistogramState.IsVisible.
src/EventLogExpert.UI/LogTable/LogTablePane.Find.cs	Publishes Find match timestamps to IFindMarkerSource.
src/EventLogExpert.UI/LogTable/Histogram/HistogramPane.razor.js	New JS interop for pan/zoom/drag/tooltip/backpressure/session gating.
src/EventLogExpert.UI/LogTable/Histogram/HistogramPane.razor.css	New styles for histogram pane, legend, markers, forced-colors hatching.
src/EventLogExpert.UI/LogTable/Histogram/HistogramPane.razor.cs	New pane logic: scan/build, aggregate/render, navigation history, scoping, markers.
src/EventLogExpert.UI/LogTable/Histogram/HistogramPane.razor	New Razor markup for histogram UI + legend + live announcements.
src/EventLogExpert.UI/LogTable/Find/IFindMarkerSource.cs	Defines Find marker source contract (owner + ascending ticks).
src/EventLogExpert.UI/LogTable/Find/FindMarkerSource.cs	Singleton implementation raising MarksChanged.
src/EventLogExpert.UI/Layout/MainContent.razor.cs	Adds histogram visibility state selection.
src/EventLogExpert.UI/Layout/MainContent.razor	Conditionally renders HistogramPane above LogTablePane.
src/EventLogExpert.UI/DependencyInjection/UiServiceCollectionExtensions.cs	Registers IFindMarkerSource in UI services.
src/EventLogExpert.UI/_Imports.razor	Imports histogram namespace for Razor usage.
src/EventLogExpert.Runtime/Menu/IMenuActionService.cs	Adds SetHistogramVisible to menu action interface.
src/EventLogExpert.Runtime/LogTable/IEventColumnView.cs	Extends view interface with bucketing/counting/time-tick APIs for histograms.
src/EventLogExpert.Runtime/LogTable/EventColumnView.cs	Implements new histogram/time-tick APIs for single-log views.
src/EventLogExpert.Runtime/LogTable/CombinedColumnView.cs	Aggregates histogram/time-tick operations across child views.
src/EventLogExpert.Runtime/Histogram/SetHistogramVisibleAction.cs	New Fluxor action for histogram visibility.
src/EventLogExpert.Runtime/Histogram/Reducers.cs	New reducer to update HistogramState.IsVisible.
src/EventLogExpert.Runtime/Histogram/IHistogramPreferencesProvider.cs	Preference provider interface for visibility persistence.
src/EventLogExpert.Runtime/Histogram/IHistogramCommands.cs	Command interface for setting histogram visibility.
src/EventLogExpert.Runtime/Histogram/HistogramSummary.cs	Generates region label + debounced window announcements.
src/EventLogExpert.Runtime/Histogram/HistogramState.cs	New Fluxor feature state for histogram visibility.
src/EventLogExpert.Runtime/Histogram/HistogramScale.cs	Sqrt scaling and stacked-segment pixel allocation utilities.
src/EventLogExpert.Runtime/Histogram/HistogramRender.cs	Render model types for aggregated bins/totals/anomalies.
src/EventLogExpert.Runtime/Histogram/HistogramGroups.cs	Defines severity groups and category grouping generator.
src/EventLogExpert.Runtime/Histogram/HistogramDimension.cs	Defines histogram group-by dimensions.
src/EventLogExpert.Runtime/Histogram/HistogramData.cs	Defines scanned base histogram data representation.
src/EventLogExpert.Runtime/Histogram/HistogramConstants.cs	Defines histogram bucket/category caps.
src/EventLogExpert.Runtime/Histogram/HistogramCommands.cs	Dispatches visibility action.
src/EventLogExpert.Runtime/Histogram/HistogramBuilder.cs	Builds histogram base data by scanning the active view.
src/EventLogExpert.Runtime/Histogram/HistogramAggregator.cs	Downsamples base bins into render bins; flags anomalies.
src/EventLogExpert.Runtime/Histogram/Effects.cs	Persists visibility preference and hydrates on store init.
src/EventLogExpert.Runtime/FilterLenses/IFilterLensCommands.cs	Adds ShowTimeRange command to lens API.
src/EventLogExpert.Runtime/FilterLenses/FilterLensFactory.cs	Adds factory for inclusive UTC time-range lens.
src/EventLogExpert.Runtime/FilterLenses/FilterLensCommands.cs	Implements ShowTimeRange by pushing a time-range lens.
src/EventLogExpert.Runtime/DependencyInjection/RuntimeServiceCollectionExtensions.cs	Registers IHistogramCommands in runtime DI.
src/EventLogExpert.Eventing/Common/Events/LevelSeverity.cs	Adds dense severity slot helpers for histogram bucketing.
src/EventLogExpert.Eventing/Common/Events/IEventColumnReader.cs	Extends reader interface with histogram bucketing/counting/time-tick APIs.
src/EventLogExpert.Eventing/Common/Events/EventColumnStoreReader.cs	Implements new reader APIs over EventColumnStore.
src/EventLogExpert.Eventing/Common/Events/EventColumnStore.cs	Implements survivor-scoped bucketing/counting and time-tick span.
src/EventLogExpert.Eventing/Common/Events/EventColumnPool.cs	Adds TryGetIndex to resolve pooled strings for fast bucketing.

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Copilot reviewed 58 out of 58 changed files in this pull request and generated 4 comments.

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Copilot reviewed 61 out of 61 changed files in this pull request and generated 2 comments.

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