fixed gwinDestroy() and added gwinGetAbsoluteCoordinates()

include/gwin/gwin.h

@@ -336,6 +336,17 @@ extern "C" {
 	 */
 	bool_t gwinGetEnabled(GHandle gh);
 
+	/**
+	 * @brief	Get absolute coordinates of a window
+	 *
+	 * @param[in] gh		The window
+	 * @param[out] x		The absolut x coordinate
+	 * @param[out] y		The absolut y coordinate
+	 *
+	 * @api
+	 */
+	void gwinGetAbsoluteCoordinates(GHandle gh, coord_t *x, coord_t *y);
+
 	/**
 	 * @brief	Move a window
 	 *

src/gwin/gwin.c

@@ -181,11 +181,16 @@ GHandle gwinGWindowCreate(GDisplay *g, GWindowObject *pgw, const GWindowInit *pI
 
 void gwinDestroy(GHandle gh) {
 	#if GWIN_NEED_HIERARCHY
-		// kill your children as long as you have any
+		// fix hierarchy structure
-		while (gh->child) {
+		if (gh->parent->child == gh) {
-			GHandle tmp = gh->child;
+			// we are the first child
-			gh->child = gh->child->sibling;
+			gh->parent->child = gh->sibling;
-			gwinDestroy(tmp);
+		} else {
+			// find our predecessor
+			GHandle tmp = gh->parent->child;
+			while (tmp->sibling != gh)
+				tmp = tmp->sibling;
+			tmp->sibling = gh->sibling;
 		}
 	#endif
 	
@@ -269,6 +274,22 @@ bool_t gwinGetEnabled(GHandle gh) {
 	#endif
 }
 
+void gwinGetAbsoluteCoordinates(GHandle gh, coord_t *x, coord_t *y) {
+	#if GWIN_NEED_HIERARCHY
+		GHandle tmp;
+
+		// sum up all relative coordinates up to the root parent
+		for (*x = 0, *y = 0, tmp = gh; tmp; tmp = tmp->parent) {
+			*x += tmp->x;
+			*y += tmp->y;
+		}
+
+	#else
+		*x = gh->x;
+		*y = gh->y;
+	#endif
+}
+
 void gwinMove(GHandle gh, coord_t x, coord_t y) {
 	_gwm_redim(gh, x, y, gh->width, gh->height);
 }