g1.setColor(Color.WHITE);
g1.fillRect(0, 0, WIDTH, HEIGHT);
g1.setColor(Color.LIGHT_GRAY);
g1.setStroke(new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0, new float[] { 1.5F }, 0));
for (int i = 1; i < 9; i++) {
g1.drawLine(1, 1 + (i * (HEIGHT / 9)), 499, 1 + (i * (HEIGHT / 9)));
g1.drawLine(1 + (i * (WIDTH / 9)), 1, 1 + (i * (WIDTH / 9)), 499);
}
g1.setColor(Color.RED);
VariableNumber x = model.getMatrix().getVariables()[xVar];
x.setRangeIntervallo(x.getIndexMin(xMin), x.getIndexMax(xMax), yMin, yMax, yVar);