Adds a check before every UIA function call to ensure the terminal (specifically the buffer) is initialized before doing work. Both the `ScreenInfoUiaProvider` and the `UiaTextRange` are now covered.
## References
Closes#11135#10971 & #11042
## Detailed Description of the Pull Request / Additional comments
Originally, I tried applying this heuristic to all the `RuntimeClassInitialize` on `UiaTextRangeBase` with the philosophy of "a range pointing to an invalid buffer is invalid itself", but that caused a regression on [MSFT 33353327](https://microsoft.visualstudio.com/OS/_workitems/edit/33353327).
`IUiaData` also has `GetTextBuffer()` return a `TextBuffer&`, which cannot be checked for nullness. Instead, I decided to add a function to `IUiaData` that checks if we have a valid state. Since this is shared with Conhost and Conhost doesn't have this issue, I simply make that function say that it's always in a valid state.
## Validation Steps Performed
- [X] Narrator can detect newly created terminals
- [X] (On Windows Server 2022) Windows Terminal does not hang on launch
## Summary of the Pull Request
Block selections were always read and displayed as line selections in UIA. This fixes that.
## PR Checklist
* [x] Closes#4509
## Detailed Description of the Pull Request / Additional comments
1. Expose `IsBlockSelection()` via IUiaData
2. Update the constructor to be able to take in a block selection parameter
3. Make ScreenInfoUiaProviders pass step 1 output into step 2 constructor
4. Update all instances of `UiaTextRange::GetTextRects()` to include this new flag
## Validation Steps Performed
Manually tested.
Additional tests would be redundant as GetTextRects() is tested in the text buffer.
- When performing chunk selection, the expansion now occurs at the time
of the selection, not the rendering of the selection
- `GetSelectionRects()` was moved to the `TextBuffer` and is now shared
between ConHost and Windows Terminal
- Some of the selection variables were renamed for clarity
- Selection COORDs are now in the Text Buffer coordinate space
- Fixes an issue with Shift+Click after performing a Multi-Click
Selection
## References
This also contributes to...
- #4509: UIA Box Selection
- #2447: UIA Signaling for Selection
- #1354: UIA support for Wide Glyphs
Now that the expansion occurs at before render-time, the selection
anchors are an accurate representation of what is selected. We just need
to move `GetText` to the `TextBuffer`. Then we can have those three
issues just rely on code from the text buffer. This also means ConHost
gets some of this stuff for free 😀
### TextBuffer
- `GetTextRects` is the abstracted form of `GetSelectionRects`
- `_ExpandTextRow` is still needed to handle wide glyphs properly
### Terminal
- Rename...
- `_boxSelection` --> `_blockSelection` for consistency with ConHost
- `_selectionAnchor` --> `_selectionStart` for consistency with UIA
- `_endSelectionPosition` --> `_selectionEnd` for consistency with
UIA
- Selection anchors are in Text Buffer coordinates now
- Really rely on `SetSelectionEnd` to accomplish appropriate chunk
selection and shift+click actions
## Validation Steps Performed
- Shift+Click
- Multi-Click --> Shift+Click
- Chunk Selection at...
- top of buffer
- bottom of buffer
- random region in scrollback
Closes#4465Closes#4547
## Summary of the Pull Request
We used to return multiple text ranges to represent one selection. We only support one selection at a time, so we should only return one range.
Additionally, I moved all TriggerSelection() calls to the renderer from Terminal to TermControl for consistency. This ensures we only call it _once_ when we make a change to our selection state.
## References
#2447 - helps polish Signaling for Selection
#4465 - This is more apparent as the problem holding back Signaling for Selection
## PR Checklist
* [x] Closes#4452
Tested using Accessibility Insights.
* Make search a shared component for conhost and terminal
* Remove inclusion of deprecated interface file
* Code review changes, remove text buffer modification in Terminal
* remove unreferenced objects to fix build errors
* Fix test failure, guarantee uiaData object is correctly initialized in Search
* minor comment typo fix and format fix
* minor PR comments change
* ColorSeclection directly throw and return
* remove coordAnchor initialization
* minor method signature change
Refactors the accessibility providers (ScreenInfoUiaProvider and UiaTextRange) into a better separated model between ConHost and Windows Terminal.
ScreenInfoUiaProviderBase and UiaTextRangeBase are introduced. ConHost and Windows Terminal implement their own versions of ScreenInfoUiaProvider and UiaTextRange that inherit from their respective base classes.
WindowsTerminal's ScreenInfoUiaProvider --> TermControlUiaProvider
