Use DwmGetWindowAttribute for Shell#getLocation to avoid shadow margins

GetWindowRect includes invisible shadow borders on Windows 10/11,
causing
Shell#getLocation to return coordinates offset by ~9px from the visible
frame. Replaced with DwmGetWindowAttribute(DWMWA_EXTENDED_FRAME_BOUNDS)
to
report the true window bounds in screen space, with GetWindowRect as a
fallback if DWM is unavailable.

Author: ShahzaibIbrahim

bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os.c

@@ -7,9 +7,6 @@
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
- *
- * Contributors:
- *    IBM Corporation - initial API and implementation
  *******************************************************************************/
 
 /* Note: This file was auto-generated by org.eclipse.swt.tools.internal.JNIGenerator */
@@ -1513,6 +1510,22 @@ JNIEXPORT jboolean JNICALL OS_NATIVE(DuplicateHandle)
 }
 #endif
 
+#ifndef NO_DwmGetWindowAttribute
+JNIEXPORT jint JNICALL OS_NATIVE(DwmGetWindowAttribute)
+	(JNIEnv *env, jclass that, jlong arg0, jint arg1, jobject arg2, jint arg3)
+{
+	RECT _arg2, *lparg2=NULL;
+	jint rc = 0;
+	OS_NATIVE_ENTER(env, that, DwmGetWindowAttribute_FUNC);
+	if (arg2) if ((lparg2 = getRECTFields(env, arg2, &_arg2)) == NULL) goto fail;
+	rc = (jint)DwmGetWindowAttribute((HWND)arg0, arg1, lparg2, arg3);
+fail:
+	if (arg2 && lparg2) setRECTFields(env, arg2, lparg2);
+	OS_NATIVE_EXIT(env, that, DwmGetWindowAttribute_FUNC);
+	return rc;
+}
+#endif
+
 #ifndef NO_DwmSetWindowAttribute
 JNIEXPORT jboolean JNICALL OS_NATIVE(DwmSetWindowAttribute)
 	(JNIEnv *env, jclass that, jlong arg0, jint arg1, jintArray arg2, jint arg3)

bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.h

@@ -7,9 +7,6 @@
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
- *
- * Contributors:
- *    IBM Corporation - initial API and implementation
  *******************************************************************************/
 
 /* Note: This file was auto-generated by org.eclipse.swt.tools.internal.JNIGenerator */
@@ -133,6 +130,7 @@ typedef enum {
 	DrawThemeBackground_FUNC,
 	DrawThemeText_FUNC,
 	DuplicateHandle_FUNC,
+	DwmGetWindowAttribute_FUNC,
 	DwmSetWindowAttribute_FUNC,
 	EMREXTCREATEFONTINDIRECTW_1sizeof_FUNC,
 	EMR_1sizeof_FUNC,

bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/win32/OS.java

@@ -1862,6 +1862,7 @@ public class OS extends C {
 	public static final int WM_XBUTTONDBLCLK = 0x020D;
 	public static final int XBUTTON1 = 0x1;
 	public static final int XBUTTON2 = 0x2;
+	public static final int DWMWA_EXTENDED_FRAME_BOUNDS = 9;
 
 public static int VERSION (int major, int minor) {
 	return major << 16 | minor;
@@ -3022,6 +3023,10 @@ public static int HRESULT_FROM_WIN32(int x) {
 public static final native boolean GetWindowPlacement (long hWnd, WINDOWPLACEMENT lpwndpl);
 /** @param hWnd cast=(HWND) */
 public static final native boolean GetWindowRect (long hWnd, RECT lpRect);
+/**
+ * @param hwnd cast=(HWND)
+ * */
+public static final native int DwmGetWindowAttribute (long hwnd, int dwAttribute, RECT pvAttribute, int cbAttribute);
 /**
  * @param hWnd cast=(HWND)
  * @param hRgn cast=(HRGN)

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Shell.java

@@ -1015,9 +1015,13 @@ public int getImeInputMode () {
 
 @Override Point getLocationInPixels () {
 	if (OS.IsIconic (handle)) return super.getLocationInPixels ();
-	RECT rect = new RECT ();
-	OS.GetWindowRect (handle, rect);
-	return new Point (rect.left, rect.top);
+	RECT rect = new RECT();
+	OS.GetWindowRect(handle, rect);
+	int hr = OS.DwmGetWindowAttribute(handle, OS.DWMWA_EXTENDED_FRAME_BOUNDS, rect, RECT.sizeof);
+	if (hr != 0) {
+		OS.GetWindowRect(handle, rect);
+	}
+	return new Point(rect.left, rect.top);
 }
 
 @Override