adj->step_increment = px2sp(10);
adj->step_increment = sp2float(px2sp(10));
setup_adjustment(GtkAdjustment* adj, gfloat size, gfloat page_size){  g_return_if_fail(adj != NULL);  adj->lower = 0.0;  adj->page_size = page_size;  adj->step_increment = px2sp(10);  adj->page_increment = page_size;  adj->upper = size;  if (adj->upper < 0) adj->upper = 0.0;  if (adj->value > adj->upper - page_size) {    adj->value = floatMax(0, adj->upper - page_size);    gtk_adjustment_value_changed(adj);  }  gtk_adjustment_changed(adj);}