if (op.type == OPERATION_IMPROPER_AXIS)
scale = -scale;
sb.append("draw pgva").append(m).append(label).append("_").append(
j + 1).append(" width 0.05 scale ").append(scale).append(" ").append(
Escape.escape(v));
v.scaleAdd(-2, op.normalOrAxis, v);
boolean isPA = (principalAxis != null && op.index == principalAxis.index);
sb.append(Escape.escape(v)).append(
"\"").append(label).append(isPA ? "*" : "").append("\" color ").append(
isPA ? "red" : op.type == OPERATION_IMPROPER_AXIS ? "blue"
: "yellow").append(";\n");