## Summary of the Pull Request
This introduces a selection marker overlay that tells the user which endpoint is currently being moved by the keyboard. The selection markers are respect font size changes and `cursor` color.
## References
#715 - Keyboard Selection
#2840 - Keyboard Selection Spec
#5804 - Mark Mode Spec
## Detailed Description of the Pull Request / Additional comments
- `TermControl` layer:
- Use a canvas (similar to the one used for hyperlinks) to be able to draw the selection markers.
- If we are notified that the selection changed, update the selection markers appropriately.
- `UpdateSelectionMarkersEventArgs` lets us distinguish between mouse and keyboard selections. `ClearMarkers` is set to true in the following cases...
1. Mouse selection, via SetEndSelectionPoint
2. `LeftClickOnTerminal`, pretty self-explanatory
3. a selection created from searching for text
- `ControlCore` layer:
- Responsible for notifying `TermControl` to update the selection markers when a selection has changed.
- Transfers info (the selection endpoint positions and which endpoint we're moving) from the terminal core to the term control.
- `TerminalCore` layer:
- Provides the viewport position of the selection endpoints.
## Validation Steps Performed
- mouse selection (w/ and w/out shift) --> no markers
- keyboard selection --> markers
- markers update appropriately when we pivot the selection
- markers scroll when you hit a boundary
- markers take the color of the cursor color setting
- markers are resized when the font size changes
Propagate show/hide window calls against the ConPTY pseudo window to the Terminal
## PR Checklist
* [x] Closes#12570
* [x] I work here
* [x] Manual Tests passed
* [x] Spec Link: →[Doc Link](https://github.com/microsoft/terminal/blob/dev/miniksa/msgs/doc/specs/%2312570%20-%20Show%20Hide%20operations%20on%20GetConsoleWindow%20via%20PTY.md)←
## Detailed Description of the Pull Request / Additional comments
- See the spec. It's pretty much everything I went through deciding on this.
## Validation Steps Performed
- [x] Manual validation against scratch application calling all of the `::ShowWindow` commands against the pseudo console "fake window" and observing the real terminal window state
Basically, this is the same as #12266, but for the `SearchBoxControl`. Trickily, the ControlCore is the one that knows if there were search results, but the TermControl has to be the one to announce it.
* [x] Will take care of #11973 once a11y team confirms
* [x] Tested manually with Narrator
* [x] Resolves a part of #6319, which I'm repurposing just to displaying the number of results in general.
* See also #3920
## Summary of the Pull Request
Brace yourselves, it's finally here. This PR does the dirty work of splitting the monolithic `TermControl` into three components. These components are:
* `ControlCore`: This encapsulates the `Terminal` instance, the `DxEngine` and `Renderer`, and the `Connection`. This is intended to everything that someone might need to stand up a terminal instance in a control, but without any regard for how the UX works.
* `ControlInteractivity`: This is a wrapper for the `ControlCore`, which holds the logic for things like double-click, right click copy/paste, selection, etc. This is intended to be a UI framework-independent abstraction. The methods this layer exposes can be called the same from both the WinUI TermControl and the WPF control.
* `TermControl`: This is the UWP control. It's got a Core and Interactivity inside it, which it uses for the actual logic of the terminal itself. TermControl's main responsibility is now
By splitting into smaller pieces, it will enable us to
* write unit tests for the `Core` and `Interactivity` bits, which we desparately need
* Combine `ControlCore` and `ControlInteractivity` in an out-of-proc core process in the future, to enable tab tearout.
However, we're not doing that work quite yet. There's still lots of work to be done to enable that, thought this is likely the biggest portion.
Ideally, this would just be methods moved wholesale from one file to another. Unfortunately, there are a bunch of cases where that didn't work as well as expected. Especially when trying to better enforce the boundary between the classes.
We've got a couple tests here that I've added. These are partially examples, and partially things I ran into while implementing this. A bunch of things from #7001 can go in now that we have this.
This PR is gonna be a huge pain to review - 38 files with 3,730 additions and 1,661 deletions is nothing to scoff at. It will also conflict 100% with anything that's targeting `TermControl`. I'm hoping we can review this over the course of the next week and just be done with it, and leave plenty of runway for 1.9 bugs in post.
## References
* In pursuit of #1256
* Proc Model: #5000
* https://github.com/microsoft/terminal/projects/5
## PR Checklist
* [x] Closes#6842
* [x] Closes https://github.com/microsoft/terminal/projects/5#card-50760249
* [x] Closes https://github.com/microsoft/terminal/projects/5#card-50760258
* [x] I work here
* [x] Tests added/passed
* [n/a] Requires documentation to be updated
## Detailed Description of the Pull Request / Additional comments
* I don't love the names `ControlCore` and `ControlInteractivity`. Open to other names.
* I added a `ICoreState` interface for "properties that come from the `ControlCore`, but consumers of the `TermControl` need to know". In the future, these will all need to be handled specially, because they might involve an RPC call to retrieve the info from the core (or cache it) in the window process.
* I've added more `EventArgs` to make more events proper `TypedEvent`s.
* I've changed how the TerminalApp layer requests updated TaskbarProgress state. It doesn't need to pump TermControl to raise a new event anymore.
* ~~Something that snuck into this branch in the very long history is the switch to `DCompositionCreateSurfaceHandle` for the `DxEngine`. @miniksa wrote this originally in 30b8335, I'm just finally committing it here. We'll need that in the future for the out-of-proc stuff.~~
* I reverted this in c113b65d9. We can revert _that_ commit when we want to come back to it.
* I've changed the acrylic handler a decent amount. But added tests!
* All the `ThrottledFunc` things are left in `TermControl`. Some might be able to move down into core/interactivity, but once we figure out how to use a different kind of Dispatcher (because a UI thread won't necessarily exist for those components).
* I've undoubtably messed up the merging of the locking around the appearance config stuff recently
## Validation Steps Performed
I've got a rolling list in https://github.com/microsoft/terminal/issues/6842#issuecomment-810990460 that I'm updating as I go.
This is a small refactor on my way to much bigger, more painful refactors. This PR does five things:
* `TermControl.*` has historically had all the control-relevant EventArgs defined in the same file as TermControl. That's just added clutter to the files, clutter that could have been in it's own place. We'll move all those event arg to their own files.
* We'll also move `IDirectKeyListener` to its own file while we're at it.
* We'll update some of `TermControl`'s old `DEFINE`/`DECLARE_TYPED_EVENT` macros to the newer `TYPED_EVENT` macro, which is a bit nicer.
* We'll change `TermControl.TitleChanged` to a typed event. I needed that for a future PR, so let's just do it here
* While we're updating `TYPED_EVENT` macros, let's do `TerminalPage` too.
### checklist
* [x] I work here
* [x] This is work for #1256, but we've got a long way to go before that works.
