public void paintItem(Graphics g, int x1, int y1, int x2, int y2) {
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
PaintableScale xScale = getPropertyValue(xScaleKey);
PaintableScale yScale = getPropertyValue(yScaleKey);
Color color = getPropertyValue(colorKey);
Double min = xScale.getMin(), max = xScale.getMax();
Double range = max - min;
int w = x2 - x1 + 1;
int h = y2 - y1 + 1;
int px = -1, py = -1;
g.setColor(Color.black);
if (xScale.getMin() < 0.0 && xScale.getMax() > 0.0) {
double zf = xScale.fractionalOffset(0.0);
int x = x1 + (int) Math.round(zf * (double) w);
g.drawLine(x, y1, x, y2);
}
if (yScale.getMin() < 0.0 && yScale.getMax() > 0.0) {
double zf = yScale.fractionalOffset(0.0);
int y = y2 - (int) Math.round(zf * (double) h);
g.drawLine(x1, y, x2, y);
}
g.setColor(color);
for (int x = x1; x <= x2; x++) {
Double xInput = min + ((double) (x - x1) / (double) w) * range;
Double yOutput = function.eval(xInput);
if (yOutput != null) {
double yf = yScale.fractionalOffset(yOutput);
int y = y2 - (int) Math.round(yf * (double) h);
if (px != -1 && py != -1) {
g.drawLine(px, py, x, y);
}
px = x;
py = y;
} else {
px = py = -1;
}
}
}
