refactor(new_editor): split utility window semantics from workspace

new_editor/app/Platform/Win32/EditorFloatingWindowPlacement.cpp

@@ -0,0 +1,46 @@
+#include "Platform/Win32/EditorFloatingWindowPlacement.h"
+
+#include <algorithm>
+
+namespace XCEngine::UI::Editor::App {
+
+namespace {
+
+constexpr LONG kFloatingWindowTopOffset = 24;
+
+}
+
+RECT BuildEditorFloatingWindowRect(
+    const POINT& screenPoint,
+    LONG preferredWidth,
+    LONG preferredHeight,
+    LONG fallbackWidth,
+    LONG fallbackHeight) {
+    const LONG resolvedWidth = preferredWidth > 0 ? preferredWidth : fallbackWidth;
+    const LONG resolvedHeight = preferredHeight > 0 ? preferredHeight : fallbackHeight;
+    const LONG left = screenPoint.x - resolvedWidth / 2;
+    const LONG top = screenPoint.y - kFloatingWindowTopOffset;
+    RECT rect = {
+        left,
+        top,
+        left + resolvedWidth,
+        top + resolvedHeight
+    };
+
+    const HMONITOR monitor = MonitorFromPoint(screenPoint, MONITOR_DEFAULTTONEAREST);
+    MONITORINFO monitorInfo = {};
+    monitorInfo.cbSize = sizeof(monitorInfo);
+    if (monitor != nullptr && GetMonitorInfoW(monitor, &monitorInfo)) {
+        const RECT& workArea = monitorInfo.rcWork;
+        const LONG width = rect.right - rect.left;
+        const LONG height = rect.bottom - rect.top;
+        rect.left = (std::max)(workArea.left, (std::min)(rect.left, workArea.right - width));
+        rect.top = (std::max)(workArea.top, (std::min)(rect.top, workArea.bottom - height));
+        rect.right = rect.left + width;
+        rect.bottom = rect.top + height;
+    }
+
+    return rect;
+}
+
+} // namespace XCEngine::UI::Editor::App