protected StringBuilder header() {
		StringBuilder b = new StringBuilder();
		b.append("%!PS-Adobe-3.0 EPSF-3.0\n");
		b.append(boundingBox).append("\n");
		b.append("0.3 setlinewidth\n");
		b.append("%% x y w h highlight\n" +
				 "/highlight {\n" +
				 "        4 dict begin\n" +
				 "        /h exch def\n" +
				 "        /w exch def\n" +
				 "        /y exch def\n" +
				 "        /x exch def\n" +
				 "        gsave\n" +
				 "        newpath\n" +
				 "        x y moveto\n" +
				 "        0 h rlineto     % up to left corner\n" +
				 "        w 0 rlineto     % to upper right corner\n" +
				 "        0 h neg rlineto % to lower right corner\n" +
				 "        w neg 0 rlineto % back home to lower left corner\n" +
				 "        closepath\n" +
				 "        .95 .83 .82 setrgbcolor\n" +
				 "        fill\n" +
				 "        grestore\n" +
				 "        end\n" +
				 "} def\n");

		return b;
	}
Compute the header separately because we need to wait for the bounding box
tool/src/org/antlr/v4/gui/PostScriptDocument.java