ui: advanced positioning system (not finished)

src/widget_core/widget_core.c

@@ -10,10 +10,17 @@ int32_t rsize_to_value(int32_t size, enum rsize rsize);
 
 void init_widget(widget_t *w, widget_t *w_parent, WINDOW **win, char *title) {
   w->id = m_id++;
-  w->x = 0;
-  w->y = 0;
-  w->m_x = 0;
-  w->m_y = 0;
+  w->sz.x = 0;
+  w->sz.y = 0;
+  w->ps.x = 0;
+  w->ps.y = 0;
+  if (w_parent != NULL && w_parent->w_parent != NULL) { /* not root element of the window */
+    w->m.x = w_parent->m.x;
+    w->m.y = w_parent->m.y;
+  } else {
+    w->m.x = 0;
+    w->m.y = 0;
+  }
   w->parent_win = win;
   w->w_parent = w_parent;
   w->callback = NULL;

src/widget_core/widget_core.h

@@ -77,14 +77,22 @@ enum rsize {
 typedef struct widget_t {
   int64_t id;
   char title[DIALOGUE_TITLE];
-  int64_t x;
-  int64_t y;
-  int64_t m_x;
-  int64_t m_y;
   struct {
     int64_t y;
     int64_t x;
-  } cur;
+  } cur; /* cursor position */
+  struct {
+    int64_t y;
+    int64_t x;
+  } sz; /* size */
+  struct {
+    int64_t y;
+    int64_t x;
+  } m; /* margin (relative to the parent) */
+  struct {
+    int64_t y;
+    int64_t x;
+  } ps; /* position (relative to the window) */
   WINDOW *const *parent_win;
   struct widget_t *w_parent;
   void (*callback)(callback_args_t *args);