case CONSTRAINT_PT_PT_COINCIDENT: return SLVS_C_POINTS_COINCIDENT;
case CONSTRAINT_PT_ON_LINE: return SLVS_C_PT_ON_LINE;
case CONSTRAINT_PT_ON_CIRCLE: return SLVS_C_PT_ON_CIRCLE;
+ case CONSTRAINT_MIDDLE_POINT: return SLVS_C_AT_MIDPOINT;
case CONSTRAINT_PT_PT_DISTANCE: return SLVS_C_PT_PT_DISTANCE;
case CONSTRAINT_PT_LINE_DISTANCE: return SLVS_C_PT_LINE_DISTANCE;
case CONSTRAINT_ANGLE: return SLVS_C_ANGLE;
case SLVS_C_POINTS_COINCIDENT: return CONSTRAINT_PT_PT_COINCIDENT;
case SLVS_C_PT_ON_LINE: return CONSTRAINT_PT_ON_LINE;
case SLVS_C_PT_ON_CIRCLE: return CONSTRAINT_PT_ON_CIRCLE;
+ case SLVS_C_AT_MIDPOINT: return CONSTRAINT_MIDDLE_POINT;
case SLVS_C_PT_PT_DISTANCE: return CONSTRAINT_PT_PT_DISTANCE;
case SLVS_C_PT_LINE_DISTANCE: return CONSTRAINT_PT_LINE_DISTANCE;
case SLVS_C_EQUAL_LENGTH_LINES: return CONSTRAINT_EQUAL_LINES;