-//int ProcessList_add(Process *myproc, ProcessList *Process_List, guint *height);
-//int ProcessList_remove(Process *myproc, ProcessList *Process_List);
+// out : success (0) and height
+int ProcessList_add(ProcessList *Process_List, guint pid, LttTime *birth,
+ guint *height);
+// out : success (0) and height
+int ProcessList_remove(ProcessList *Process_List, guint pid, LttTime *birth);
+
+guint ProcessList_get_pixels(ProcessList *Process_List);
+
+// Returns 0 on success
+gint ProcessList_get_process_pixels(ProcessList *Process_List,
+ guint pid, LttTime *birth,
+ guint *x, guint *height);