src/java.desktop/share/classes/sun/java2d/marlin/MarlinRenderingEngine.java

*** 243,253 ****
  
          if (at == null) {
              widthScale = 1.0f;
          } else if ((at.getType() & (AffineTransform.TYPE_GENERAL_TRANSFORM  |
                                      AffineTransform.TYPE_GENERAL_SCALE)) != 0) {
!             widthScale = (float)Math.sqrt(at.getDeterminant());
          } else {
              // First calculate the "maximum scale" of this transform.
              double A = at.getScaleX();       // m00
              double C = at.getShearX();       // m01
              double B = at.getShearY();       // m10
--- 243,254 ----
  
          if (at == null) {
              widthScale = 1.0f;
          } else if ((at.getType() & (AffineTransform.TYPE_GENERAL_TRANSFORM  |
                                      AffineTransform.TYPE_GENERAL_SCALE)) != 0) {
!             // Determinant may be negative (flip), use its absolute value:
!             widthScale = (float)Math.sqrt(Math.abs(at.getDeterminant()));
          } else {
              // First calculate the "maximum scale" of this transform.
              double A = at.getScaleX();       // m00
              double C = at.getShearX();       // m01
              double B = at.getShearY();       // m10