Implement InitialPosition and CenterOnLaunch in the SUI (#13605)

## Summary of the Pull Request
`InitialPosition` and `CenterOnLaunch` can now be edited in the SUI

## PR Checklist
* [x] Closes #9075 
* [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've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

## Detailed Description of the Pull Request / Additional comments
`InitialPosition` follows the same style as `LaunchSize`, with a number box for the x coordinate and a number box for the y coordinate. When there is no value for either of these coordinates, the respective number box is empty (and displays the text `Undefined`). 

## Validation Steps Performed
They work

.github/actions/spelling/allow/allow.txt

@@ -97,5 +97,7 @@ versioned
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+XBox
+YBox
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src/cascadia/TerminalSettingsEditor/Launch.cpp

@@ -6,6 +6,9 @@
 #include "Launch.g.cpp"
 #include "EnumEntry.h"
 
+#include <LibraryResources.h>
+
+using namespace winrt::Windows::UI::Xaml;
 using namespace winrt::Windows::UI::Xaml::Navigation;
 using namespace winrt::Windows::Foundation;
 using namespace winrt::Microsoft::Terminal::Settings::Model;
@@ -24,6 +27,14 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         {
             FindName(L"DefaultTerminalDropdown");
         }
+
+        Automation::AutomationProperties::SetName(LaunchModeComboBox(), RS_(L"Globals_LaunchModeSetting/Text"));
+        Automation::AutomationProperties::SetHelpText(LaunchModeComboBox(), RS_(L"Globals_LaunchModeSetting/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
+        Automation::AutomationProperties::SetHelpText(PosXBox(), RS_(L"Globals_InitialPosXBox/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
+        Automation::AutomationProperties::SetHelpText(PosYBox(), RS_(L"Globals_InitialPosYBox/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
+        Automation::AutomationProperties::SetHelpText(UseDefaultLaunchPositionCheckbox(), RS_(L"Globals_DefaultLaunchPositionCheckbox/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
+        Automation::AutomationProperties::SetName(CenterOnLaunchToggle(), RS_(L"Globals_CenterOnLaunch/Text"));
+        Automation::AutomationProperties::SetHelpText(CenterOnLaunchToggle(), RS_(L"Globals_CenterOnLaunch/[using:Windows.UI.Xaml.Controls]ToolTipService/ToolTip"));
     }
 
     void Launch::OnNavigatedTo(const NavigationEventArgs& e)

src/cascadia/TerminalSettingsEditor/Launch.xaml

@@ -150,17 +150,6 @@
                               Style="{StaticResource ComboBoxSettingStyle}" />
                 </local:SettingContainer>
 
-
-                <!--  Launch Mode  -->
-                <local:SettingContainer x:Name="Globals_LaunchMode"
-                                        x:Uid="Globals_LaunchMode">
-                    <ComboBox AutomationProperties.AccessibilityView="Content"
-                              ItemTemplate="{StaticResource EnumComboBoxTemplate}"
-                              ItemsSource="{x:Bind ViewModel.LaunchModeList}"
-                              SelectedItem="{x:Bind ViewModel.CurrentLaunchMode, Mode=TwoWay}"
-                              Style="{StaticResource ComboBoxSettingStyle}" />
-                </local:SettingContainer>
-
                 <!--  Windowing Behavior  -->
                 <local:SettingContainer x:Uid="Globals_WindowingBehavior">
                     <ComboBox AutomationProperties.AccessibilityView="Content"
@@ -206,6 +195,68 @@
                                         Value="{x:Bind ViewModel.InitialRows, Mode=TwoWay}" />
                     </Grid>
                 </local:SettingContainer>
+
+                <!--  Launch Parameters  -->
+                <local:SettingContainer x:Uid="Globals_LaunchParameters"
+                                        CurrentValue="{x:Bind ViewModel.LaunchParametersCurrentValue, Mode=OneWay}"
+                                        Style="{StaticResource ExpanderSettingContainerStyle}">
+                    <Grid RowSpacing="10">
+                        <Grid.RowDefinitions>
+                            <RowDefinition Height="Auto" />
+                            <RowDefinition Height="Auto" />
+                            <RowDefinition Height="Auto" />
+                        </Grid.RowDefinitions>
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition Width="*" />
+                            <ColumnDefinition Width="Auto" />
+                        </Grid.ColumnDefinitions>
+                        <TextBlock x:Uid="Globals_LaunchModeSetting"
+                                   Grid.Row="0"
+                                   Grid.Column="0"
+                                   VerticalAlignment="Center" />
+                        <ComboBox x:Name="LaunchModeComboBox"
+                                  Grid.Row="0"
+                                  Grid.Column="1"
+                                  MinWidth="240"
+                                  AutomationProperties.AccessibilityView="Content"
+                                  ItemTemplate="{StaticResource EnumComboBoxTemplate}"
+                                  ItemsSource="{x:Bind ViewModel.LaunchModeList}"
+                                  SelectedItem="{x:Bind ViewModel.CurrentLaunchMode, Mode=TwoWay}"
+                                  Style="{StaticResource ComboBoxSettingStyle}" />
+                        <TextBlock x:Uid="Globals_LaunchPosition"
+                                   Grid.Row="1"
+                                   Grid.Column="0"
+                                   VerticalAlignment="Center" />
+                        <StackPanel Grid.Row="1"
+                                    Grid.Column="1">
+                            <StackPanel Orientation="Horizontal"
+                                        Spacing="4">
+                                <muxc:NumberBox x:Name="PosXBox"
+                                                x:Uid="Globals_InitialPosXBox"
+                                                IsEnabled="{x:Bind local:Converters.InvertBoolean(ViewModel.UseDefaultLaunchPosition), Mode=OneWay}"
+                                                Style="{StaticResource LaunchSizeNumberBoxStyle}"
+                                                Value="{x:Bind ViewModel.InitialPosX, Mode=TwoWay}" />
+                                <muxc:NumberBox x:Name="PosYBox"
+                                                x:Uid="Globals_InitialPosYBox"
+                                                IsEnabled="{x:Bind local:Converters.InvertBoolean(ViewModel.UseDefaultLaunchPosition), Mode=OneWay}"
+                                                Style="{StaticResource LaunchSizeNumberBoxStyle}"
+                                                Value="{x:Bind ViewModel.InitialPosY, Mode=TwoWay}" />
+                            </StackPanel>
+                            <CheckBox x:Name="UseDefaultLaunchPositionCheckbox"
+                                      x:Uid="Globals_DefaultLaunchPositionCheckbox"
+                                      IsChecked="{x:Bind ViewModel.UseDefaultLaunchPosition, Mode=TwoWay}" />
+                        </StackPanel>
+                        <TextBlock x:Uid="Globals_CenterOnLaunch"
+                                   Grid.Row="2"
+                                   Grid.Column="0"
+                                   VerticalAlignment="Center" />
+                        <ToggleSwitch x:Name="CenterOnLaunchToggle"
+                                      Grid.Row="2"
+                                      Grid.Column="1"
+                                      IsOn="{x:Bind ViewModel.CenterOnLaunch, Mode=TwoWay}"
+                                      Style="{StaticResource ToggleSwitchInExpanderStyle}" />
+                    </Grid>
+                </local:SettingContainer>
             </StackPanel>
         </StackPanel>
     </ScrollViewer>

src/cascadia/TerminalSettingsEditor/LaunchViewModel.cpp

@@ -5,16 +5,20 @@
 #include "LaunchViewModel.h"
 #include "LaunchViewModel.g.cpp"
 #include "EnumEntry.h"
+#include <LibraryResources.h>
 
 using namespace winrt::Windows::UI::Xaml::Navigation;
 using namespace winrt::Windows::Foundation;
 using namespace winrt::Microsoft::Terminal::Settings::Model;
+using namespace winrt::Windows::UI::Xaml::Data;
 
 namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
 {
     LaunchViewModel::LaunchViewModel(Model::CascadiaSettings settings) :
         _Settings{ settings }
     {
+        _useDefaultLaunchPosition = isnan(InitialPosX()) && isnan(InitialPosY());
+
         INITIALIZE_BINDABLE_ENUM_SETTING(FirstWindowPreference, FirstWindowPreference, FirstWindowPreference, L"Globals_FirstWindowPreference", L"Content");
         INITIALIZE_BINDABLE_ENUM_SETTING(LaunchMode, LaunchMode, LaunchMode, L"Globals_LaunchMode", L"Content");
         // More options were added to the JSON mapper when the enum was made into [Flags]
@@ -23,6 +27,118 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         _LaunchModeList.RemoveAt(6); // fullscreenFocus
         _LaunchModeList.RemoveAt(3); // maximizedFullscreen
         INITIALIZE_BINDABLE_ENUM_SETTING(WindowingBehavior, WindowingMode, WindowingMode, L"Globals_WindowingBehavior", L"Content");
+
+        // Add a property changed handler to our own property changed event.
+        // This propagates changes from the settings model to anybody listening to our
+        // unique view model members.
+        PropertyChanged([this](auto&&, const PropertyChangedEventArgs& args) {
+            const auto viewModelProperty{ args.PropertyName() };
+            if (viewModelProperty == L"CenterOnLaunch")
+            {
+                _NotifyChanges(L"LaunchParametersCurrentValue");
+            }
+        });
+    }
+
+    winrt::hstring LaunchViewModel::LaunchParametersCurrentValue()
+    {
+        const auto launchModeString = CurrentLaunchMode().as<EnumEntry>()->EnumName();
+        const auto centerOnLaunchString = CenterOnLaunch() ? RS_(L"Globals_CenterOnLaunchOn") : RS_(L"Globals_CenterOnLaunchOff");
+
+        winrt::hstring result;
+
+        if (UseDefaultLaunchPosition())
+        {
+            result = fmt::format(L"{}, {}, {}", launchModeString, RS_(L"Globals_LaunchModeDefault/Content"), centerOnLaunchString);
+        }
+        else
+        {
+            const std::wstring xPosString = isnan(InitialPosX()) ? RS_(L"Globals_LaunchModeDefault/Content").c_str() : std::to_wstring(gsl::narrow_cast<int>(InitialPosX()));
+            const std::wstring yPosString = isnan(InitialPosY()) ? RS_(L"Globals_LaunchModeDefault/Content").c_str() : std::to_wstring(gsl::narrow_cast<int>(InitialPosY()));
+            result = fmt::format(L"{}, ({},{}), {}", launchModeString, xPosString, yPosString, centerOnLaunchString);
+        }
+        return result;
+    }
+
+    double LaunchViewModel::InitialPosX()
+    {
+        const auto x = _Settings.GlobalSettings().InitialPosition().X;
+        // If there's no value here, return NAN - XAML will ignore it and
+        // put the placeholder text in the box instead
+        const auto xCoord = x.try_as<int64_t>();
+        return xCoord.has_value() ? gsl::narrow_cast<double>(xCoord.value()) : NAN;
+    }
+
+    double LaunchViewModel::InitialPosY()
+    {
+        const auto y = _Settings.GlobalSettings().InitialPosition().Y;
+        // If there's no value here, return NAN - XAML will ignore it and
+        // put the placeholder text in the box instead
+        const auto yCoord = y.try_as<int64_t>();
+        return yCoord.has_value() ? gsl::narrow_cast<double>(yCoord.value()) : NAN;
+    }
+
+    void LaunchViewModel::InitialPosX(double xCoord)
+    {
+        winrt::Windows::Foundation::IReference<int64_t> xCoordRef;
+        // If the value was cleared, xCoord will be NAN, so check for that
+        if (!isnan(xCoord))
+        {
+            xCoordRef = gsl::narrow_cast<int64_t>(xCoord);
+        }
+        const LaunchPosition newPos{ xCoordRef, _Settings.GlobalSettings().InitialPosition().Y };
+        _Settings.GlobalSettings().InitialPosition(newPos);
+        _NotifyChanges(L"LaunchParametersCurrentValue");
+    }
+
+    void LaunchViewModel::InitialPosY(double yCoord)
+    {
+        winrt::Windows::Foundation::IReference<int64_t> yCoordRef;
+        // If the value was cleared, yCoord will be NAN, so check for that
+        if (!isnan(yCoord))
+        {
+            yCoordRef = gsl::narrow_cast<int64_t>(yCoord);
+        }
+        const LaunchPosition newPos{ _Settings.GlobalSettings().InitialPosition().X, yCoordRef };
+        _Settings.GlobalSettings().InitialPosition(newPos);
+        _NotifyChanges(L"LaunchParametersCurrentValue");
+    }
+
+    void LaunchViewModel::UseDefaultLaunchPosition(bool useDefaultPosition)
+    {
+        _useDefaultLaunchPosition = useDefaultPosition;
+        if (useDefaultPosition)
+        {
+            InitialPosX(NAN);
+            InitialPosY(NAN);
+            _NotifyChanges(L"InitialPosX", L"InitialPosY");
+        }
+        _NotifyChanges(L"UseDefaultLaunchPosition", L"LaunchParametersCurrentValue");
+    }
+
+    bool LaunchViewModel::UseDefaultLaunchPosition()
+    {
+        return _useDefaultLaunchPosition;
+    }
+
+    winrt::Windows::Foundation::IInspectable LaunchViewModel::CurrentLaunchMode()
+    {
+        return winrt::box_value<winrt::Microsoft::Terminal::Settings::Editor::EnumEntry>(_LaunchModeMap.Lookup(_Settings.GlobalSettings().LaunchMode()));
+    }
+
+    void LaunchViewModel::CurrentLaunchMode(const winrt::Windows::Foundation::IInspectable& enumEntry)
+    {
+        if (const auto ee = enumEntry.try_as<winrt::Microsoft::Terminal::Settings::Editor::EnumEntry>())
+        {
+            const auto setting = winrt::unbox_value<LaunchMode>(ee.EnumValue());
+            _Settings.GlobalSettings().LaunchMode(setting);
+            _NotifyChanges(L"LaunchParametersCurrentValue");
+        }
+    }
+
+    winrt::Windows::Foundation::Collections::IObservableVector<winrt::Microsoft::Terminal::Settings::Editor::EnumEntry> LaunchViewModel::LaunchModeList()
+    {
+        return _LaunchModeList;
     }
 
     winrt::Windows::Foundation::IInspectable LaunchViewModel::CurrentDefaultProfile()

src/cascadia/TerminalSettingsEditor/LaunchViewModel.h

@@ -14,6 +14,14 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
     public:
         LaunchViewModel(Model::CascadiaSettings settings);
 
+        winrt::hstring LaunchParametersCurrentValue();
+        double InitialPosX();
+        double InitialPosY();
+        void InitialPosX(double xCoord);
+        void InitialPosY(double yCoord);
+        void UseDefaultLaunchPosition(bool useDefaultPosition);
+        bool UseDefaultLaunchPosition();
+
         IInspectable CurrentDefaultProfile();
         void CurrentDefaultProfile(const IInspectable& value);
         winrt::Windows::Foundation::Collections::IObservableVector<Model::Profile> DefaultProfiles() const;
@@ -22,16 +30,25 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         void CurrentDefaultTerminal(const IInspectable& value);
         winrt::Windows::Foundation::Collections::IObservableVector<Model::DefaultTerminal> DefaultTerminals() const;
 
+        // We cannot use the macro for LaunchMode because we want to insert an event into the setter
+        winrt::Windows::Foundation::IInspectable CurrentLaunchMode();
+        void CurrentLaunchMode(const winrt::Windows::Foundation::IInspectable& enumEntry);
+        winrt::Windows::Foundation::Collections::IObservableVector<winrt::Microsoft::Terminal::Settings::Editor::EnumEntry> LaunchModeList();
+
         GETSET_BINDABLE_ENUM_SETTING(FirstWindowPreference, Model::FirstWindowPreference, _Settings.GlobalSettings().FirstWindowPreference);
-        GETSET_BINDABLE_ENUM_SETTING(LaunchMode, Model::LaunchMode, _Settings.GlobalSettings().LaunchMode);
         GETSET_BINDABLE_ENUM_SETTING(WindowingBehavior, Model::WindowingMode, _Settings.GlobalSettings().WindowingBehavior);
 
+        PERMANENT_OBSERVABLE_PROJECTED_SETTING(_Settings.GlobalSettings(), CenterOnLaunch);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_Settings.GlobalSettings(), StartOnUserLogin);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_Settings.GlobalSettings(), InitialRows);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_Settings.GlobalSettings(), InitialCols);
 
     private:
         Model::CascadiaSettings _Settings;
+        bool _useDefaultLaunchPosition;
+
+        winrt::Windows::Foundation::Collections::IObservableVector<winrt::Microsoft::Terminal::Settings::Editor::EnumEntry> _LaunchModeList;
+        winrt::Windows::Foundation::Collections::IMap<Model::LaunchMode, winrt::Microsoft::Terminal::Settings::Editor::EnumEntry> _LaunchModeMap;
     };
 };
 

src/cascadia/TerminalSettingsEditor/LaunchViewModel.idl

@@ -11,6 +11,11 @@ namespace Microsoft.Terminal.Settings.Editor
     {
         LaunchViewModel(Microsoft.Terminal.Settings.Model.CascadiaSettings settings);
 
+        String LaunchParametersCurrentValue { get; };
+        Double InitialPosX;
+        Double InitialPosY;
+        Boolean UseDefaultLaunchPosition;
+
         IInspectable CurrentDefaultProfile;
         IObservableVector<Microsoft.Terminal.Settings.Model.Profile> DefaultProfiles { get; };
 
@@ -26,6 +31,7 @@ namespace Microsoft.Terminal.Settings.Editor
         IInspectable CurrentWindowingBehavior;
         IObservableVector<Microsoft.Terminal.Settings.Editor.EnumEntry> WindowingBehaviorList { get; };
 
+        PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, CenterOnLaunch);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, StartOnUserLogin);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Int32, InitialRows);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Int32, InitialCols);