## Summary of the Pull Request
In the original implementation, we used two different orderings for the color tables. The WT color table used ANSI order, while the conhost color table used a Windows-specific order. This PR standardizes on the ANSI color order everywhere, so the usage of indexed colors is consistent across both parts of the code base, which will hopefully allow more of the code to be shared one day.
## References
This is another small step towards de-duplicating `AdaptDispatch` and `TerminalDispatch` for issue #3849, and is essentially a followup to the SGR dispatch refactoring in PR #6728.
## PR Checklist
* [x] Closes#11461
* [x] CLA signed.
* [x] Tests added/passed
* [ ] Documentation updated.
* [ ] Schema updated.
* [x] I've discussed this with core contributors already. Issue number where discussion took place: #11461
## Detailed Description of the Pull Request / Additional comments
Conhost still needs to deal with legacy attributes using Windows color order, so those values now need to be transposed to ANSI colors order when creating a `TextAttribute` object. This is done with a simple mapping table, which also handles the translation of the default color entries, so it's actually slightly faster than the original code.
And when converting `TextAttribute` values back to legacy console attributes, we were already using a mapping table to handle the narrowing of 256-color values down to 16 colors, so we just needed to adjust that table to account for the translation from ANSI to Windows, and then could make use of the same table for both 256-color and 16-color values.
There are also a few places in conhost that read from or write to the color tables, and those now need to transpose the index values. I've addressed this by creating separate `SetLegacyColorTableEntry` and `GetLegacyColorTableEntry` methods in the `Settings` class which take care of the mapping, so it's now clearer in which cases the code is dealing with legacy values, and which are ANSI values.
These methods are used in the `SetConsoleScreenBufferInfoEx` and `GetConsoleScreenBufferInfoEx` APIs, as well as a few place where color preferences are handled (the registry, shortcut links, and the properties dialog), none of which are particularly sensitive to performance. However, we also use the legacy table when looking up the default colors for rendering (which happens a lot), so I've refactored that code so the default color calculations now only occur once per frame.
The plus side of all of this is that the VT code doesn't need to do the index translation anymore, so we can finally get rid of all the calls to `XTermToWindowsIndex`, and we no longer need a separate color table initialization method for conhost, so I was able to merge a number of color initialization methods into one. We also no longer need to translate from legacy values to ANSI when generating VT sequences for conpty.
The one exception to that is the 16-color VT renderer, which uses the `TextColor::GetLegacyIndex` method to approximate 16-color equivalents for RGB and 256-color values. Since that method returns a legacy index, it still needs to be translated to ANSI before it can be used in a VT sequence. But this should be no worse than it was before.
One more special case is conhost's secret _Color Selection_ feature. That uses `Ctrl`+Number and `Alt`+Number key sequences to highlight parts of the buffer, and the mapping from number to color is based on the Windows color order. So that mapping now needs to be transposed, but that's also not performance sensitive.
The only thing that I haven't bothered to update is the trace logging code in the `Telemetry` class, which logs the first 16 entries in the color table. Those entries are now going to be in a different order, but I didn't think that would be of great concern to anyone.
## Validation Steps Performed
A lot of unit tests needed to be updated to use ANSI color constants when setting indexed colors, where before they might have been expecting values in Windows order. But this replaced a wild mix of different constants, sometimes having to use bit shifting, as well as values mapped with `XTermToWindowsIndex`, so I think the tests are a whole lot clearer now. Only a few cases have been left with literal numbers where that seemed more appropriate.
In addition to getting the unit tests working, I've also manually tested the behaviour of all the console APIs which I thought could be affected by these changes, and confirmed that they produced the same results in the new code as they did in the original implementation.
This includes:
- `WriteConsoleOutput`
- `ReadConsoleOutput`
- `SetConsoleTextAttribute` with `WriteConsoleOutputCharacter`
- `FillConsoleOutputAttribute` and `FillConsoleOutputCharacter`
- `ScrollConsoleScreenBuffer`
- `GetConsoleScreenBufferInfo`
- `GetConsoleScreenBufferInfoEx`
- `SetConsoleScreenBufferInfoEx`
I've also manually tested changing colors via the console properties menu, the registry, and shortcut links, including setting default colors and popup colors. And I've tested that the "Quirks Mode" is still working as expected in PowerShell.
In terms of performance, I wrote a little test app that filled a 80x9999 buffer with random color combinations using `WriteConsoleOutput`, which I figured was likely to be the most performance sensitive call, and I think it now actually performs slightly better than the original implementation.
I've also tested similar code - just filling the visible window - with SGR VT sequences of various types, and the performance seems about the same as it was before.
<!-- Enter a brief description/summary of your PR here. What does it fix/what does it change/how was it tested (even manually, if necessary)? -->
## Summary of the Pull Request
The TerminalSettings object we create from profiles no longer gets passed into the control, instead, a child of that object gets passed into the control. Any overrides the control makes to the settings then live in the child. So, when we do a settings reload, we simply update the child's parent and the overrides will remain.
<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist
* [ ] Closes #xxx
* [x] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [ ] Tests added/passed
* [ ] Documentation updated. If checked, please file a pull request on [our docs repo](https://github.com/MicrosoftDocs/terminal) and link it here: #xxx
* [ ] Schema updated.
* [x] I work here
<!-- Describe how you validated the behavior. Add automated tests wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
Manual testing
Introduces the following UI controls to the ColorSchemes page:
- "Add new" button
- next to dropdown selector
- adds a new color scheme named ("Color Scheme #" where # is the number of color schemes you have)
- "Rename" Button
- next to the selector
- replaces the ComboBox with a TextBox and the accept/cancel buttons appear
- "Delete" button
- bottom of the page
- opens flyout, when confirmed, deletes the current color scheme and selects another one
This also adds a Delete button to the Profiles page. The Hide checkbox was moved above the Delete button.
## References
#1564 - Settings UI
#6800 - Settings UI Completion Epic
## Detailed Description of the Pull Request / Additional comments
**Color Schemes:**
- Deleting a color scheme selects another one from the list available
- Rename replaces the combobox with a textbox to allow editing
- The Add New button creates a new color scheme named "Color Scheme X" where X is the number of schemes defined
- In-box color schemes cannot be deleted
**Profile:**
- Deleting a profile selects another one from the list available
- the rename button does not exist (yet), because it needs a modification to the NavigationView's Header Template
- The delete button is disabled for in-box profiles (CMD and Windows Powershell) and dynamic profiles
## Validation Steps Performed
**Color Schemes - Add New**
✅ Creates a new color scheme named "Color Scheme X" (X being the number of color schemes)
✅ The new color scheme can be renamed/deleted/modified
**Color Schemes - Rename**
✅ You cannot rename an in-box color scheme
✅ The rename button has a tooltip
✅ Clicking the rename button replaces the combobox with a textbox
✅ Accept --> changes name
✅ Cancel --> does not change the name
✅ accepting/cancelling the rename operation updates the combo box appropriately
**Color Schemes - Delete**
✅ Clicking delete produces a flyout to confirm deletion
✅ Deleting a color scheme removes it from the list and select the one under it
✅ Deleting the last color scheme selects the last available color scheme after it's deleted
✅ In-box color schemes have the delete button disabled, and a disclaimer appears next to it
**Profile- Delete**
✅ Base layer presents a disclaimer at the top, and hides the delete button
✅ Dynamic and in-box profiles disable the delete button and show the appropriate disclaimer next to the disabled button
✅ Clicking delete produces a flyout to confirm deletion
✅ Regular profiles have a delete button that is styled appropriately
✅ Clicking the delete profile button opens a content dialog. Confirmation deletes the profile and navigates to the profile indexed under it (deleting the last one redirects to the last one)
## Demo
Refer to this post [here](https://github.com/microsoft/terminal/pull/8403#issuecomment-747545651.
Confirmation flyout demo: https://github.com/microsoft/terminal/pull/8403#issuecomment-747657842
* Correct the behaviour of parsing `rgb:R/G/B`. It should be interpreted
as `RR/GG/BB` instead of `0R/0G/0B`
* Add support for `rgb:RRR/GGG/BBB` and `rgb:RRRR/GGGG/BBBB`. The
behaviour of 12 bit variants is to repeat the first digit at the end,
e.g. `rgb:123/456/789` becomes `rgb:1231/4564/7897`.
* Add support for `#` formats. We are following the rules of
[XParseColor] by interpreting `#RGB` as `R000G000B000`.
* Add support for XOrg app color names, which are supported by xterm, VTE
and many other terminal emulators.
* Multi-parameter OSC 4 is now supported.
* The chaining of OSC 10-12 is not yet supported. But the parameter
validation is relaxed by parsing the parameters as multi-params but
only use the first one, which means `\e]10;rgb:R/G/B;` and
`\e]10:rgb:R/G/B;invalid` will execute `OSC 10` with the first color
correctly. This fixes some of the issues mentioned in #942 but not
all of them.
[XParseColor]: https://linux.die.net/man/3/xparsecolorCloses#3715
James Holderness
PankajBhojwani
Carlos Zamora
Chester Liu