Allow querying global cursor position

If a platform implements this, e.g. xeyes can track cursor when the
window is not receiving mouse movement events

xbanan/Base.cpp

@@ -1967,6 +1967,16 @@ BAN::ErrorOr<void> handle_packet(Client& client_info, BAN::ConstByteSpan packet)
 			}
 
 			const auto [root_x, root_y] = get_window_position(wid);
+
+			int32_t root_cursor_x, root_cursor_y;
+			if (g_platform_ops.query_pointer)
+				g_platform_ops.query_pointer(&root_cursor_x, &root_cursor_y);
+			else
+			{
+				root_cursor_x = root_x + window.cursor_x;
+				root_cursor_y = root_y + window.cursor_y;
+			}
+
 			xQueryPointerReply reply {
 				.type = X_Reply,
 				.sameScreen = xTrue,
@@ -1974,10 +1984,10 @@ BAN::ErrorOr<void> handle_packet(Client& client_info, BAN::ConstByteSpan packet)
 				.length = 0,
 				.root = g_root.windowId,
 				.child = static_cast<CARD32>(child_wid),
-				.rootX = static_cast<INT16>(root_x + window.cursor_x),
+				.rootX = static_cast<INT16>(root_cursor_x),
-				.rootY = static_cast<INT16>(root_y + window.cursor_y),
+				.rootY = static_cast<INT16>(root_cursor_y),
-				.winX = static_cast<INT16>(window.cursor_x),
+				.winX = static_cast<INT16>(root_cursor_x - root_x),
-				.winY = static_cast<INT16>(window.cursor_y),
+				.winY = static_cast<INT16>(root_cursor_y - root_y),
 				.mask = static_cast<KeyButMask>(g_keymask | g_butmask),
 			};
 			TRY(encode(client_info.output_buffer, reply));

xbanan/Platform.h

@@ -61,6 +61,8 @@ struct PlatformOps
 	void (*request_fullscreen)(PlatformWindow*, bool fullscreen);
 	/* Warp pointer */
 	void (*warp_pointer)(int32_t x, int32_t y, bool relative);
+	/* Get global position of the pointer */
+	void (*query_pointer)(int32_t* x, int32_t* y);
 	/* Create a system cursor */
 	BAN::ErrorOr<BAN::UniqPtr<PlatformCursor>> (*create_system_cursor)(SystemCursorType);
 	/* Create cursor from custom bitmap */

xbanan/SDL3/sdl3.cpp

@@ -348,6 +348,14 @@ static void sdl3_warp_pointer(int32_t x, int32_t y, bool relative)
 	SDL_WarpMouseGlobal(x, y);
 }
 
+static void sdl3_query_pointer(int32_t* x, int32_t* y)
+{
+	float cx, cy;
+	SDL_GetGlobalMouseState(&cx, &cy);
+	*x = cx;
+	*y = cy;
+}
+
 static BAN::ErrorOr<BAN::UniqPtr<PlatformCursor>> sdl3_create_system_cursor(SystemCursorType type)
 {
 	static constexpr SDL_SystemCursor cursor_type_map[] {
@@ -428,6 +436,7 @@ PlatformOps g_platform_ops = {
 	.request_reposition   = sdl3_request_reposition,
 	.request_fullscreen   = sdl3_request_fullscreen,
 	.warp_pointer         = sdl3_warp_pointer,
+	.query_pointer        = sdl3_query_pointer,
 	.create_system_cursor = sdl3_create_system_cursor,
 	.create_bitmap_cursor = sdl3_create_bitmap_cursor,
 	.set_cursor           = sdl3_set_cursor,

xbanan/banan-os/banan-os.cpp

@@ -154,6 +154,12 @@ static void bananos_warp_pointer(int32_t x, int32_t y, bool relative)
 	(void)relative;
 }
 
+static void bananos_query_pointer(int32_t* x, int32_t* y)
+{
+	(void)x;
+	(void)y;
+}
+
 static BAN::ErrorOr<BAN::UniqPtr<PlatformCursor>> bananos_create_system_cursor(SystemCursorType type)
 {
 	(void)type;
@@ -198,6 +204,7 @@ PlatformOps g_platform_ops = {
 	.request_reposition   = bananos_request_reposition,
 	.request_fullscreen   = bananos_request_fullscreen,
 	.warp_pointer         = bananos_warp_pointer,
+	.query_pointer        = nullptr, /* bananos_query_pointer */
 	.create_system_cursor = bananos_create_system_cursor,
 	.create_bitmap_cursor = bananos_create_bitmap_cursor,
 	.set_cursor           = bananos_set_cursor,