paint_widget(math_view);
gtk_math_view_paint(math_view);
hadjustment_value_changed(GtkAdjustment* adj, GtkMathView* math_view){  g_return_if_fail(adj != NULL);  g_return_if_fail(math_view != NULL);  if (adj->value > adj->upper - adj->page_size) adj->value = adj->upper - adj->page_size;  if (adj->value < adj->lower) adj->value = adj->lower;  math_view->old_top_x = math_view->top_x;  math_view->top_x = static_cast<int>(adj->value);  if (math_view->old_top_x != math_view->top_x)    paint_widget(math_view);}