Termina 0.17.0

Behavior Changes

• The event loop no longer runs queued work after it stops (#400)
  • When the loop stops, it drops all work that is still in the queue. This includes work that Post or InvokeAsync queued before the call to Shutdown(). Earlier versions could run that work.
  • A task that InvokeAsync returned for dropped work ends as canceled with TaskCanceledException. The task ends this way even when the token of the caller is not canceled.
  • InvokeAsync called after the loop stopped returns a canceled task. Post called after the loop stopped does not run its work.
  • A queued CommitAsync call for inline output ends as canceled in the same way.
  • Code that must run during shutdown must run before Shutdown(), not as queued work.
• RequestRedraw can merge with a redraw request that is already queued (#400)
  • Change the state before you call RequestRedraw(). A render that runs between the call and the state change can draw the old state. The loop then skips the merged request.
  • A RedrawRequested.Instance that an input source writes to the event channel always renders.
  • Input subscribers still see every redraw request as RedrawRequested.

New Features

• Added an opt-in inline presentation mode (#373, fixes #366 and #370)

  • TerminalPresentationMode.Inline keeps settled output in the primary buffer.
  • IInlineOutput commits stable layouts above one bounded live region.
  • ScrollInputMode.NativeTerminal leaves selection and scrollback under terminal control.
  • IInlineTerminalControl adds relative cursor operations without a change to IAnsiTerminal. AnsiTerminal and VirtualTerminal implement the new contract.
  • Full-screen mode remains the default mode.

• Added semantic clipboard content for copyable text (#374, fixes #367)

  • WithSemanticContent separates complete clipboard text from compact display text.
  • TryCopy reports clipboard failure and preserves the current selection.

• Added a modified Enter key capability result (#375, fixes #240)

  • Termina queries active Kitty keyboard flags without a terminal-name guess.
  • TerminalInputCapabilitiesChanged reports whether modified Enter keys remain distinct.
  • TerminaApplication.InputCapabilities exposes the latest result.
  • Windows console records report native modifier support.

• Added prompt history cancellation (#376, fixes #368)

  • CancelHistoryNavigation restores the draft that existed before history navigation.
  • The API resets history navigation without a change to current method signatures.

• Added pointer-aware wheel routing (#376, fixes #240)

  • MouseScrollEvent preserves zero-based pointer coordinates and keyboard modifiers.
  • Termina routes wheel input to the measured scroll region under the pointer.
  • ScrollableContainerNode now implements the current IScrollable contract.

• Added an optional panel background surface (#379, fixes #378)

  • PanelNode.WithBackground(Color) sets the surface. PanelNode.Background reads it.
  • The panel fills its complete bounds, including the border cells.
  • A child that resets its colors returns to the surface. A child that selects its own background keeps it.
  • A scrollable or streaming node in a surface panel keeps its screen bounds, so the mouse wheel reaches it.
  • A panel without a background keeps its current behavior.

Performance

• The event loop renders once for each batch of queued events (#400)
  • The loop processes the events that are queued when a batch starts, and then renders once. Events that arrive during the batch go to the next batch.
  • Before, the loop rendered the full page after every event. A slow render let the queue grow without limit.
  • 20 RequestRedraw calls in one loop turn now cause 2 to 3 renders. Before, they caused 24 renders.
  • The cursor blink alone now causes about 1.9 renders each second. Before, it caused about 4.3.
  • The final frame is the same as before.
• TextAreaNode measures a long line cheaply (#400)
  • Measure keeps the column counts of the text until the text changes. A call with unchanged text takes under 0.01 ms and allocates no memory. Before, it took 43 ms and allocated 16 MB for a line of 600,000 characters.
  • DisplayWidth.GetColumnCount returns the length of printable ASCII text without an allocation.
  • TextAreaNode keeps one line wrap for each width. A layout that measures and renders at different widths no longer wraps the line twice for each frame.
  • One render of an unchanged 600,000-character line takes under 1 ms instead of 69 ms, and allocates 0.27 MB instead of 32 MB.
• Ctrl+Q exits fast with a large transcript or a large paste (#400)
  • The loop waits for each batch with WaitToReadAsync and stops at a shutdown request. Before, the loop kept running while events kept arriving.
  • An app with a 1,000,000-character line now exits in about 360 ms. Before, it did not exit within 90 s.
• Wrapping a very long line is now linear in its length (#398, fixes #397, first shipped in 0.16.4)
  • StyledWordWrapper, WordWrapper, and TextAreaNode no longer re-measure the rest of a long line for every wrapped row.
• Text writes to the diffing terminal allocate less (#379)
  • DiffingTerminal.Write skips the grapheme parse when every char is printable ASCII. All other text uses the old loop.
  • A full-screen frame of a panel with a background allocates 40 KB instead of 400 KB. It renders in about 0.7 ms instead of 1.5 ms.
  • This change applies to every app and every render, not only panels. The output is the same.

Bug Fixes

• Fixed tail follow after a large content update (#383)

  • A ScrollableContainerNode with TailWhenAtBottom stopped at the old offset after the content grew by more than 2 rows. This happens often now, because the loop renders once for each batch of events.
  • Measure now reads IsNearBottom before it replaces the content height.
  • When the content shrinks, Measure clamps the offset to the new range. Before, a shrink could leave a blank pane.
  • A user who scrolled up stays where the user is.

• Restored all terminal and input state after a render failure

  • Termina now cancels input tasks before it propagates a render exception.
  • Termina restores the cursor, mouse modes, keyboard modes, and input mode.

• Corrected text-area prompt history traversal (#377, fixes #368)

  • Up recalls prompt history from the first visual line and saves the current draft.
  • Down restores the saved draft from the last visual line.
  • Up and Down keep their current visual movement between multiline rows.

• Made container disposal safe when layout retirement overlaps teardown (#384, first shipped in 0.16.2)

  • ContainerNode.Dispose() now claims teardown atomically, so concurrent disposal no longer completes the same reactive invalidation subject twice.

• Added a way to place the cursor in a pre-filled text input (#395, fixes #394, first shipped in 0.16.3)

  • TextInputBaseNode.CursorPosition gets and sets the cursor as a UTF-16 index into the editable text.
  • TextInputBaseNode.MoveCursorToEnd() moves the cursor to the end of the text.

Compatibility

• Current enum values and public signatures keep their behavior. The release adds no public API change that breaks a caller, apart from the event loop behavior changes above.
• The current AnsiTerminal(bool) constructor keeps its behavior.
• An API approval test prevents accidental contract changes.

Maintenance

• Bumped Microsoft.SourceLink.GitHub to 10.0.303 (#396) and pinned System.Security.Cryptography.Pkcs to 10.0.13 in the test project (#399) to clear security advisory warnings.
• Updated Microsoft.Extensions.DependencyInjection and Microsoft.Extensions.Hosting to 10.0.11 (#380, #389).
• Updated Microsoft.CodeAnalysis.CSharp and Microsoft.CodeAnalysis.Analyzers to 5.9.0 for the repository (#387). The source generators and analyzers that ship in the package stay on 5.3.0, as in 0.16.4 (#403). Consumers keep the same .NET SDK requirement.
• Updated the incrementalist.cmd tool to 1.2.2 (#385).