widths[col], heights[line + 1], widths[col + 1], heights[line]);
cb.setRGBColorStrokeF((float)Math.random(), (float)Math.random(), (float)Math.random());
// horizontal borderline
cb.moveTo(widths[col], heights[line]);
cb.lineTo(widths[col + 1], heights[line]);
cb.stroke();
// vertical borderline
cb.setRGBColorStrokeF((float)Math.random(), (float)Math.random(), (float)Math.random());
cb.moveTo(widths[col], heights[line]);
cb.lineTo(widths[col], heights[line + 1]);
cb.stroke();