feat(obj): add lv_obj_get_height/width_visible

src/lv_core/lv_obj_pos.c

@@ -404,6 +404,34 @@ void lv_obj_get_coords_fit(const lv_obj_t * obj, lv_area_t * area)
 
 }
 
+lv_coord_t lv_obj_get_height_visible(const lv_obj_t * obj)
+{
+    lv_obj_update_layout(lv_obj_get_screen(obj));
+
+    lv_coord_t h = LV_COORD_MAX;
+    lv_obj_t * parent = lv_obj_get_parent(obj);
+    while(parent) {
+        h = LV_MIN(lv_obj_get_height_fit(parent), h);
+        parent = lv_obj_get_parent(parent);
+    }
+
+    return h == LV_COORD_MAX ? LV_DPI_DEF : h;
+}
+
+lv_coord_t lv_obj_get_width_visible(const lv_obj_t * obj)
+{
+    lv_obj_update_layout(lv_obj_get_screen(obj));
+
+    lv_coord_t w = LV_COORD_MAX;
+    lv_obj_t * parent = lv_obj_get_parent(obj);
+    while(parent) {
+        w = LV_MIN(lv_obj_get_width_fit(parent), w);
+        parent = lv_obj_get_parent(parent);
+    }
+
+    return w == LV_COORD_MAX ? LV_DPI_DEF : w;
+}
+
 lv_coord_t lv_obj_get_self_width(struct _lv_obj_t * obj)
 {
     lv_point_t p = {0, LV_COORD_MIN};

src/lv_core/lv_obj_pos.h

@@ -223,6 +223,24 @@ lv_coord_t lv_obj_get_height_fit(const struct _lv_obj_t * obj);
  */
 void lv_obj_get_coords_fit(const struct _lv_obj_t * obj, lv_area_t * area);
 
+/**
+ * Get the height which is visible on the the given object without causing overflow.
+ * If there are smaller grand parents than their height will be considered.
+ * Useful on nested scrollable objects to get a height that fills the entire visible height.
+ * @param obj       pointer to an object
+ * @return          the visible height
+ */
+lv_coord_t lv_obj_get_height_visible(const struct _lv_obj_t * obj);
+
+/**
+ * Get the widht which is visible on the the given object without causing overflow.
+ * If there are smaller grand parents than their width will be considered.
+ * Useful on nested scrollable objects to get a width that fills the entire visible width.
+ * @param obj       pointer to an object
+ * @return          the visible width
+ */
+lv_coord_t lv_obj_get_width_visible(const struct _lv_obj_t * obj);
+
 /**
  * Get the width occupied by the "parts" of the widget. E.g. the width of all columns of a table.
  * @param obj       pointer to an objects