code: public void setTransformDP(int dp) {
          this.transformDP = dp;
          if (dp < 1 || dp > 10) {
              this.transformFormat = null;
              return;
          }
          DecimalFormatSymbols dfs = new DecimalFormatSymbols();
          dfs.setDecimalSeparator('.');
          this.transformFormat = new DecimalFormat("0." 
                  + "##########".substring(0, dp), dfs);
      }
docs: Sets the number of decimal places used to write the transformation
  matrices in the SVG output.  Values in the range 1 to 10 will be used
  to configure a formatter to that number of decimal places, for all other
  values we revert to the normal {@code String} conversion of
  {@code double} primitives (approximately 16 decimals places).
  <p>
  Note that there is a separate attribute to control the number of decimal
  places for geometrical elements in the output (see
  {@link #setGeometryDP(int)}).
  
  @param dp  the number of decimal places (normally 1 to 10).
  
  @see #getTransformDP()