Merge pull request #101774 from Riteo/wayland-multiwindow-for-real-this-time

Wayland: Implement native sub-windows

Author: Repiteo

doc/classes/DisplayServer.xml

@@ -1958,6 +1958,9 @@
 		<constant name="FEATURE_NATIVE_COLOR_PICKER" value="32" enum="Feature">
 			Display server supports native color picker. [b]Linux (X11/Wayland)[/b]
 		</constant>
+		<constant name="FEATURE_SELF_FITTING_WINDOWS" value="33" enum="Feature">
+			Display server automatically fits popups according to the screen boundaries. Window nodes should not attempt to do that themselves.
+		</constant>
 		<constant name="MOUSE_MODE_VISIBLE" value="0" enum="MouseMode">
 			Makes the mouse cursor visible if it is hidden.
 		</constant>
@@ -2181,7 +2184,10 @@
 			[b]Note:[/b] This flag is implemented on macOS and Windows.
 			[b]Note:[/b] Setting this flag will [b]NOT[/b] prevent other apps from capturing an image, it should not be used as a security measure.
 		</constant>
-		<constant name="WINDOW_FLAG_MAX" value="10" enum="WindowFlags">
+		<constant name="WINDOW_FLAG_POPUP_WM_HINT" value="10" enum="WindowFlags">
+			Signals the window manager that this window is supposed to be an implementation-defined "popup" (usually a floating, borderless, untileable and immovable child window).
+		</constant>
+		<constant name="WINDOW_FLAG_MAX" value="11" enum="WindowFlags">
 			Max value of the [enum WindowFlags].
 		</constant>
 		<constant name="WINDOW_EVENT_MOUSE_ENTER" value="0" enum="WindowEvent">
@@ -2211,6 +2217,10 @@
 			Sent when the window title bar decoration is changed (e.g. [constant WINDOW_FLAG_EXTEND_TO_TITLE] is set or window entered/exited full screen mode).
 			[b]Note:[/b] This flag is implemented only on macOS.
 		</constant>
+		<constant name="WINDOW_EVENT_FORCE_CLOSE" value="8" enum="WindowEvent">
+			Sent when the window has been forcibly closed by the Display Server. The window shall immediately hide and clean any internal rendering references.
+			[b]Note:[/b] This flag is implemented only on Linux (Wayland).
+		</constant>
 		<constant name="WINDOW_EDGE_TOP_LEFT" value="0" enum="WindowResizeEdge">
 			Top-left edge of a window.
 		</constant>

doc/classes/Popup.xml

@@ -11,6 +11,7 @@
 	<members>
 		<member name="borderless" type="bool" setter="set_flag" getter="get_flag" overrides="Window" default="true" />
 		<member name="popup_window" type="bool" setter="set_flag" getter="get_flag" overrides="Window" default="true" />
+		<member name="popup_wm_hint" type="bool" setter="set_flag" getter="get_flag" overrides="Window" default="true" />
 		<member name="transient" type="bool" setter="set_transient" getter="is_transient" overrides="Window" default="true" />
 		<member name="unresizable" type="bool" setter="set_flag" getter="get_flag" overrides="Window" default="true" />
 		<member name="visible" type="bool" setter="set_visible" getter="is_visible" overrides="Window" default="false" />

doc/classes/Window.xml

@@ -670,6 +670,9 @@
 		<member name="popup_window" type="bool" setter="set_flag" getter="get_flag" default="false">
 			If [code]true[/code], the [Window] will be considered a popup. Popups are sub-windows that don't show as separate windows in system's window manager's window list and will send close request when anything is clicked outside of them (unless [member exclusive] is enabled).
 		</member>
+		<member name="popup_wm_hint" type="bool" setter="set_flag" getter="get_flag" default="false">
+			If [code]true[/code], the [Window] will signal to the window manager that it is supposed to be an implementation-defined "popup" (usually a floating, borderless, untileable and immovable child window).
+		</member>
 		<member name="position" type="Vector2i" setter="set_position" getter="get_position" default="Vector2i(0, 0)">
 			The window's position in pixels.
 			If [member ProjectSettings.display/window/subwindows/embed_subwindows] is [code]false[/code], the position is in absolute screen coordinates. This typically applies to editor plugins. If the setting is [code]true[/code], the window's position is in the coordinates of its parent [Viewport].
@@ -879,7 +882,10 @@
 			[b]Note:[/b] This flag is implemented on macOS and Windows.
 			[b]Note:[/b] Setting this flag will [b]NOT[/b] prevent other apps from capturing an image, it should not be used as a security measure.
 		</constant>
-		<constant name="FLAG_MAX" value="10" enum="Flags">
+		<constant name="FLAG_POPUP_WM_HINT" value="10" enum="Flags">
+			Signals the window manager that this window is supposed to be an implementation-defined "popup" (usually a floating, borderless, untileable and immovable child window).
+		</constant>
+		<constant name="FLAG_MAX" value="11" enum="Flags">
 			Max value of the [enum Flags].
 		</constant>
 		<constant name="CONTENT_SCALE_MODE_DISABLED" value="0" enum="ContentScaleMode">