Sandbox::https://github.com/unoplatform/uno/pull/23924

morning4coffe-dev · 2026-07-30T18:02:41Z

GitHub Issue: closes #3848

Dependency: #23731 merged into master on September 20. This PR targets master and adds the RichEditBox layer; shared RichTextBlock implementations are reused, not copied.

PR Type:

✨ Feature

What changed? 🚀

This adds a functional WinUI-compatible RichEditBox implementation for Uno's Skia targets: Desktop, Skia-on-Android/iOS, and Skia WebAssembly.

User-visible behavior

Adds interactive rich-text editing with keyboard, pointer, touch grippers, selection, caret scrolling, formatting accelerators, spell-check integration, and IME composition.
Implements the public Text Object Model surface used by RichEditTextDocument, ITextRange, ITextSelection, character/paragraph formats, tracked ranges, clipboard operations, streams, and undo/redo.
Renders character and paragraph formatting, lists, tabs, links, inline images, bidirectional text, MathML/Unicode math, OpenType MATH variants/assemblies, and large documents through bounded incremental layout.
Adds Text/Text2 automation, rich text-object children, native Win32 UIA integration, and a standalone external UIA probe.
Adds safe bounded RTF import/export, including editable table metadata, object fallbacks, active-destination stripping, hyperlink export allowlisting, and parser/resource limits.
Uses WinUI's hyperlink launch policy: file/res are blocked, HTTP(S) is trusted, and other absolute schemes require confirmation. The cross-platform confirmation adapter is scoped to the editor's XamlRoot; the browser adapter additionally rejects JavaScript execution URLs.
Adds eight SamplesApp pages covering basic editing, character/paragraph formatting, events, formatting accelerators, interactive editing, automation, and the all-features surface.

What came from `/winui-port`

The public/MUX-observable control behavior was ported and aligned from WinUI sources using the /winui-port workflow. The changed files retain MUX references or source-location comments for:

RichEditBox_Partial.cpp control/template behavior
RichEditBoxAutomationPeer_Partial.cpp automation class/control semantics
TextBoxBaseAutomationPeer.cpp and WindowLessSiteHost.cpp host/provider policy; the private windowless text provider is represented by a managed adapter, not claimed as a source port
TextBoxBase.cpp/.h editing, focus, flyout, proofing, gripper, and selection behavior
Launcher.cpp scheme eligibility and trusted/untrusted launch policy
TextSelectionManager.cpp, TextControlFlyoutHelper.*, and CoreServices behavior shared with the existing text stack

Public parity tests are intentionally unsuffixed where they can run against both Uno and native WinUI.

What had to be implemented from scratch

WinUI delegates the backing editor to non-public Windows RichEdit/Text Services and COM internals. Those APIs are not public or portable, so they could not be losslessly copied into Uno. The following cross-platform pieces are managed Uno implementations built from scratch against the public observable contract:

piece-based text story storage, indexed formatting runs, range gravity/rebasing, and bounded undo history
TOM range/selection navigation, formatting, geometry, clipboard, and stream behavior
retained/incremental rich-text shaping and layout over the shared Skia TextBlock pipeline
bounded RTF parsing/writing, table-control preservation, image/object fallbacks, and active-content sanitization
MathML/Unicode-math projection and OpenType MATH metrics, variants, and glyph assemblies
browser/native IME session coordination, candidate geometry, platform input proxies, and composition ownership
rich text-object automation adapters and platform UIA provider integration

Uno does not expose private ITextDocument2/ITextRange2 COM identity, OLE hosting, marshaling, apartment, reference-counting, or Windows RichEdit implementation details. The public WinUI API and observable behavior remain the compatibility boundary.

Scope and safeguards

Skia renderer only; native Android/UIKit/DOM renderers are not introduced.
Large stories switch to bounded paragraph layout; list state is checkpointed so local edits remain incremental.
Async clipboard providers are bounded, canceled when superseded, and generation-gated before commit.
RTF/MathML inputs enforce size, nesting, token, run, image/object, and projected-output budgets.
Unsafe external-template, macro/form, mail-merge, embedded-font, active-field, and blocked-scheme content is not re-emitted as active RTF.
The existing IValueProvider ABI is retained, but RichEditBox continues to advertise the WinUI Text/Text2 patterns rather than a Value pattern.

Coverage

Adds approximately 750 runtime-test methods across public WinUI parity, Skia behavior, rendering, editing, IME, clipboard, RTF, math, automation, and scaling suites.
Adds a signed native-WinUI test path and external Win32 UIA client for reference validation.
Adds Uno-specific RichEditBox documentation and a platform support/limitations matrix.

Validation performed

The following includes validation from earlier revisions. Current review-follow-up results and platform limits are recorded in the review replies.

Analyzer-strict net10.0 Skia SamplesApp build.
Targeted Skia runtime tests for editing, RTF tables, streams, clipboard ordering/cancellation, IME restart, automation input limits, math, bounded layout, and security budgets.
Skia WebAssembly publish, including C#/TypeScript interop generation.
Signed x64 native WinUI SamplesApp MSIX build and filtered native-reference execution. WinUI flattens edited RTF tables, so Uno's safer table-descriptor preservation tests are explicitly marked as Uno-specific contracts.
DocFX 2.73.2 rendered articles/controls/RichEditBox.html with no page-specific diagnostics. The full local docs build retains the known missing external/generated TOC baseline.

PR Checklist ✅

🧪 Added Runtime tests, UI tests, or a manual test sample (for bug fixes / features, if applicable)
📚 Docs have been added/updated following the documentation template (for bug fixes / features)
🖼️ Validated PR Screenshots Compare Test Run results.
❗ Contains NO breaking changes
👀 Reviewed 2 other open pull requests (optional but appreciated!)

github-actions · 2026-07-30T18:03:00Z

Claude finished @morning4coffe-dev's task in 15m 47s —— View job

Code Review — `feat(richeditbox): implement Skia support`

Verdict: fix-first — two medium accessibility gaps should be addressed before merge; the resource leak is low-severity but straightforward to fix.

Findings (inline comments posted)

#	Severity	File	Finding
1	Medium	`RichEditBoxAutomationPeer.cs:42`	`PatternInterface.TextEdit` removed from `GetPatternCore` — Win32 has a `GetTextEditProvider` fallback, but macOS and X11 UIA providers do not. Non-Win32 Skia accessibility silently advertises no `TextEdit` pattern despite `TextAdapter` implementing `ITextEditProvider`.
2	Medium	`SkiaAccessibilityBase.cs:415`	`NotifyTextEditTextChangedEvent` is a no-op at the base class level; additionally, `UpdateTextValue` (which calls `uno_accessibility_update_value` on macOS) gates on `GetPattern(PatternInterface.Value)`, which returns `null` for `RichEditBox` since `Value` was intentionally removed from `GetPatternCore`. VoiceOver text sync is silently dropped for `RichEditBox`.
3	Low	`Win32ClipboardExtension.cs:126`	`ThreadLocal<HWND>` created without `trackAllValues: true` — threads that exit without calling `DestroyWindow` leak message-only windows. The field's `Dispose` can't enumerate values to clean up.

Cross-cutting notes

Solid areas:

All async void paths (PasteFromClipboard, BeginPasteFromClipboard) are wrapped in comprehensive try/catch with correct exception-type handling and re-throw on fatal exceptions.
event Action<T> violation in TextInputPlugin was correctly converted to EventHandler<TextInputConnectionCreatedEventArgs> — no new violations introduced.
RichEditBox.Properties.skia.cs DP registrations use FrameworkPropertyMetadata, correct callback signatures, and default(T) for primitive defaults. AcceptsReturn defaults to true (correct WinUI behavior for RichEditBox, unlike TextBox).
RTF parser security limits (MaxRtfInputLength = 16 MB, MaxGroupDepth = 256, MaxParsedGroups = 65 536) and FeatureConfiguration.RichEditBox.MaxRtfImportCharacters are appropriately bounded.
Generated stubs correctly updated — __SKIA__ removed from [Uno.NotImplemented] attributes and #if guards in the Generated/ folder following the standard pattern.
ITextBoxViewHost abstraction is a clean seam that keeps TextBlock.OwningTextBox decoupled from the concrete TextBox type.

Scope note: This is a large initial implementation (~4 800-line RTF codec + full editing engine). The Win32 path is well-exercised by the new Uno.UI.RuntimeTests.Win32UiaClient harness. The two medium findings above specifically affect macOS/X11 Skia accessibility, which would otherwise be silently incomplete at the IAccessible/AT-SPI layer.

github-actions · 2026-07-30T18:11:34Z

WinAppSDK sync generator drift detected on `722c575`

The Uno.WinAppSDKSyncGenerator produced changes that are not committed on this PR.

To apply automatically (PRs from branches in this repo only): comment /apply-sync-gen on this PR and a bot will push chore: Sync generator run to the head branch.

To apply manually (required for PRs from forks):

Download the sync-generator-patch artifact from this run.

In your local checkout of the PR branch:

git apply sync-generator.patch
git add -A
git commit -m "chore: Sync generator run"
git push

Or re-run the generator locally on Windows via build\run-api-sync-tool.cmd.

github-actions · 2026-07-31T16:43:23Z

Claude finished @morning4coffe-dev's task in 4m 38s —— View job

Code Review — `feat(richeditbox): implement Skia support`

Tasks

Load context and prior review findings
Read key changed files
Review: accessibility patterns (RichEditBoxAutomationPeer.cs, SkiaAccessibilityBase.cs)
Review: resource management (Win32ClipboardExtension.cs)
Review: nullable safety in test files
Review: async/cancellation discipline, event declarations, platform suffix correctness
Post inline comments
Summarize findings

Verdict: fix-first — two medium accessibility gaps will silently break non-Win32 Skia AT clients (macOS VoiceOver, X11 AT-SPI) and should be addressed before merge. One has a companion test that locks in the broken behaviour and must be updated together.

Issues by severity

#	Severity	File	Summary
1	Medium	`RichEditBoxAutomationPeer.cs:45`	`PatternInterface.TextEdit` missing from `GetPatternCore` — macOS/X11 AT discovery fails silently
2	Medium	`SkiaAccessibilityBase.cs:420`	`NotifyAutomationEvent` gates `UpdateTextValue` on Value pattern, which `RichEditBox` doesn't advertise — VoiceOver text sync dropped
3	Medium	`Given_RichEditBox.Automation.skia.cs:53`	Test asserts `GetPattern(TextEdit)` is null, encoding the gap from finding #1 — must be updated when the fix lands or it will permanently lock in the broken state
4	Low	`Win32ClipboardExtension.cs:126`	`ThreadLocal<HWND>` without `trackAllValues: true` leaks message-only windows on thread-pool thread exit
5	Low (×5)	`Given_RichEditBox.Automation.skia.cs`, `Given_AccessibleTextBox.cs`	Nullable dereferences after `Assert.IsNotNull` — static flow analysis doesn't narrow through MSTest assertions; add `!`-suppressors

Cross-cutting observations

Solid areas confirmed:

event Action<T> correctly avoided — TextInputPlugin.InputConnectionCreated uses EventHandler<TextInputConnectionCreatedEventArgs>. ✅
All new async void paths (PasteFromClipboard, BeginPasteFromClipboard) are wrapped in comprehensive try/catch. ✅
Platform suffix discipline is correct: Skia-specific files use .skia.cs, Win32 in Uno.UI.Runtime.Skia.Win32, etc. No native-platform code leaks into shared files. ✅
RTF parser security limits (MaxRtfInputLength = 16 MB, depth/group/output budgets, FeatureConfiguration.RichEditBox.MaxRtfImportCharacters) are well-bounded. ✅
[GeneratedDependencyProperty] used correctly in RichEditBox.Properties.skia.cs with FrameworkPropertyMetadata, correct callbacks, default(T) for primitive defaults, and AcceptsReturn = true matching WinUI's RichEditBox contract (not TextBox's false). ✅

Finding #1 + #3 are coupled: adding PatternInterface.TextEdit to GetPatternCore in RichEditBoxAutomationPeer.cs will cause the test at Given_RichEditBox.Automation.skia.cs:53 to fail. Both must change together in one commit.

Finding #2 is independent and the fix is contained to SkiaAccessibilityBase.NotifyAutomationEvent — broadening the TextEditTextChanged / TextPatternOnTextChanged guard from GetPattern(Value) to also fall back to peer as IValueProvider.

github-actions · 2026-08-01T08:36:57Z

Claude finished @morning4coffe-dev's task in 4m 46s —— View job

Code Review — `feat(richeditbox): implement Skia support`

Tasks

Load context and prior review findings
Read key changed files (accessibility peers, clipboard extension, test files)
Check if previous findings were fixed
Review new commits for fresh issues
Post inline comments
Summarize findings

Verdict: fix-first — the two medium accessibility gaps from prior reviews remain open and should be addressed before merge. The Win32ClipboardExtension HWND leak and nullable suppressors are low-severity but straightforward.

Status of prior findings

#	Severity	Status	Finding
1	Medium	Still open	`PatternInterface.TextEdit` missing from `RichEditBoxAutomationPeer.GetPatternCore` — macOS/X11 AT discovery broken
2	Medium	Still open	`SkiaAccessibilityBase.NotifyAutomationEvent` gates on Value pattern; VoiceOver text sync dropped for `RichEditBox`
3	Medium	Still open	Companion test at `Given_RichEditBox.Automation.skia.cs:53` asserts `TextEdit` returns `null`, locking in finding #1
4	Low	Still open	`ThreadLocal<HWND>` without `trackAllValues: true` leaks message-only HWNDs
5	Low (×5)	Still open	Nullable dereferences in test files after `Assert.IsNotNull` (`Given_RichEditBox.Automation.skia.cs` ×4, `Given_AccessibleTextBox.cs` ×1)

What the latest commits addressed

The recent fix(richeditbox): resolve CI regressions commits (Jul 31–Aug 1) correctly fixed:

Stream position restore for bitmap and unknown-data clipboard setters (SetBitmap, SetUnknownData)
Various Skia CI test regressions (IME, math glyph assembly, movement probes, performance, scaling)
Missing [PlatformCondition] on a When_UnicodeMath_* test that cannot run against native RichEdit

These are all correct and do not introduce new issues.

Cross-cutting observations

Solid areas confirmed (unchanged):

event Action<T> correctly avoided — TextInputPlugin.InputConnectionCreated uses EventHandler<TextInputConnectionCreatedEventArgs>. ✅
All async void paths are wrapped in comprehensive try/catch. ✅
Platform suffix discipline is correct; Skia-specific files use .skia.cs, Win32 in Uno.UI.Runtime.Skia.Win32. ✅
RTF parser security limits are well-bounded. ✅
[GeneratedDependencyProperty] used correctly in RichEditBox.Properties.skia.cs. ✅

Findings #1 and #3 are coupled: adding PatternInterface.TextEdit to GetPatternCore will cause the test at Given_RichEditBox.Automation.skia.cs:53 to fail — both must change in the same commit.

Keeps master's unpaired-surrogate behavior (d751043) after the rebase folded it into ReadCodepoint, so script and font fallback never see a surrogate code unit as a code point. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017TzDba3gSK3uYpvLmmBmaa

Compares a lambda-local rect so CodeQL no longer reports the captured bounds comparison as identical values. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017TzDba3gSK3uYpvLmmBmaa

The single 2 MiB line is one glyph run whose vertex data exceeds WebGPU's 256 MB buffer limit, and wgpu aborts the process on the resulting validation error, losing the rest of the shard. That is a backend limitation (one op is never split across vertex arena chunks), not a RichEditBox one. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017TzDba3gSK3uYpvLmmBmaa

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github-actions · 2026-10-10T06:15:48Z

Claude encountered an error after 0s —— View job

I'll analyze this and get back to you.

MartinZikmund · 2026-10-10T06:21:34Z

Rebased onto master (d2ea69f60bc) and force-pushed with a lease on @MartinZikmund's behalf; head is now f41df4d6277.

Conflict: only UnicodeText.cs. Master's d751043a118 (lone surrogates) and this PR's 137c4f12985 fixed the same loop. I kept the PR's ReadCodepoint and moved master's behavior into it: a lone surrogate now reads as U+FFFD, so script and font fallback never get a bare surrogate (de7f8340eeb). Master's Given_UnicodeText tests cover this.
CodeQL "comparison of identical values" in RichEditBoxUiaClient: this was a false positive. The bounds check now uses a rect local to the lambda (5756c744f36).
New Desktop Linux WebGPU leg (added on master after this PR's last green run): the run aborted in When_Bounded_Layout_Ends_Large_Story_Is_Released. The 2 MiB line is a single glyph run whose vertex data (about 857 MB) is over WebGPU's 256 MB buffer limit, and wgpu panics and aborts the process when that happens. That limit comes from the backend (PackVerts never splits a single op), not from RichEditBox, so the test now skips on WebGPU (f41df4d6277).
The three a11y validation threads are left open, as their last comments say.

Built locally in strict mode: Uno.UI.RuntimeTests.Skia, Runtime.Win32/MacOS/WebAssembly.Browser and RichEditBoxUiaClient. CI is running.

🤖 Generated with Claude Code

unodevops · 2026-10-10T06:52:43Z

🤖 Your WebAssembly Skia Sample App stage site is ready! Visit it here: https://unowasmprstaging.z20.web.core.windows.net/pr-23924/wasm-skia-net9/index.html

nventive-devops · 2026-10-10T07:45:21Z

The build 238733 found UI Test snapshots differences: skia-linux-screenshots: 118, skia-windows-screenshots: 1139

Details

skia-linux-screenshots: 118 changed over 2458
🚨🚨 Comparison Details (first 20) 🚨🚨
- ButtonClippingTestsControl.png-dark
- ButtonClippingTestsControl.png
- ClipboardTests.png-dark
- DisplayInformation.png-dark
- Buttons.png-dark
- Buttons.png
- CalendarView_Theming.png-dark
- CalendarView_Theming.png
- CompositionEffectBrush.png-dark
- CompositionEffectBrush.png
- CompositionNineGridBrush_Source_Changes.png-dark
- CompositionNineGridBrush_Source_Changes.png
- ElementLevelTheme.png-dark
- ElementLevelTheme.png
- DynamicFont.png-dark
- DynamicFont.png
- DropDownButtonPage.png-dark
- Examples.png
- Focus_FocusVisual_Properties.png-dark
- Focus_FocusVisual_Properties.png
skia-windows-screenshots: 1139 changed over 2486
🚨🚨 Comparison Details (first 20) 🚨🚨
- AnimatedBackVisualSourceSamplePage.png-dark
- AppWindowFeatures.png
- Attributed_text_Simple.png-dark
- AutoBorderStretchwithleftmargin.png-dark
- AutoBorderStretchwithleftmargin.png
- AutomationProperties_AutomationId.png
- AutoSizedPathCentered.png
- AutoSuggestBox_Keyboard.png
- BasicEnability.png-dark
- Basics_Automated.png-dark
- Basics_Automated.png
- BorderCenteredwithmargins.png-dark
- BorderCenteredwithmargins.png
- Border_Simple_No_Background_With_TextBox.png-dark
- Border_Simple_No_Background_With_TextBox.png
- Button_Events.png-dark
- Button_Events.png
- ComboBox_Legacy.png-dark
- ComboBox_Legacy.png
- CommandBarFlyoutMainPage.png-dark

unodevops · 2026-10-10T09:19:54Z

🤖 Your Docs stage site is ready! Visit it here: https://unodocsprstaging.z13.web.core.windows.net/pr-23924/docs/index.html

github-actions Bot added area/automation Categorizes an issue or PR as relevant to project automation kind/documentation platform/x11 🐧 Categorizes an issue or PR as relevant to X11 labels Jul 30, 2026

github-actions Bot assigned morning4coffe-dev Jul 30, 2026

github-actions Bot reviewed Jul 30, 2026

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Comment thread src/Uno.UI/UI/Xaml/Automation/Peers/RichEditBoxAutomationPeer.cs Resolved

github-actions Bot reviewed Jul 30, 2026

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Comment thread src/Uno.UI.Runtime/Accessibility/SkiaAccessibilityBase.cs Resolved

github-actions Bot reviewed Jul 30, 2026

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Comment thread src/Uno.UI.Runtime.Skia.Win32/ApplicationMode/DataTransfer/Win32ClipboardExtension.cs Resolved

github-code-quality Bot found potential problems Jul 30, 2026

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morning4coffe-dev force-pushed the dev/doti/port-richeditbox branch from 722c575 to dc23773 Compare July 31, 2026 16:42