protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
int w = getWidth();
int h = getHeight();
double xScale = (w - 2 * PAD) / (xMax - xMin);
double yScale = (h - 2 * PAD) / (yMax - yMin);
if (firstTime) System.out.printf("xScale = %.1f yScale = %.1f%n", xScale, yScale);
Point2D.Double origin = new Point2D.Double(); // Axes origin.
Point2D.Double offset = new Point2D.Double(); // Locate data.
if (xMax < 0) {
origin.x = w - PAD;
offset.x = origin.x - xScale * xMax;
} else if (xMin < 0) {
origin.x = PAD - xScale * xMin;
offset.x = origin.x;
} else {
origin.x = PAD;
offset.x = PAD - xScale * xMin;
}
if (yMax < 0) {
origin.y = h - PAD;
offset.y = origin.y - yScale * yMax;
} else if (yMin < 0) {
origin.y = PAD - yScale * yMin;
offset.y = origin.y;
} else {
origin.y = PAD;
offset.y = PAD - yScale * yMin;
}
if (firstTime) {
System.out.printf("origin = [%6.1f, %6.1f]%n", origin.x, origin.y);
System.out.printf("offset = [%6.1f, %6.1f]%n", offset.x, offset.y);
}
// Draw abcissa.
g2.draw(new Line2D.Double(PAD, origin.y, w - PAD, origin.y));
// Draw ordinate.
g2.draw(new Line2D.Double(origin.x, PAD, origin.x, h - PAD));
g2.setPaint(Color.red);
// Mark origin.
g2.fill(new Ellipse2D.Double(origin.x - 2, origin.y - 2, 4, 4));
// Plot data.
g2.setPaint(Color.blue);
for (int i = 0; i < x.length; i++) {
double x1 = offset.x + xScale * x[i];
double y1 = offset.y + yScale * y[i];
if (firstTime) System.out.printf("i = %d x1 = %6.1f y1 = %.1f%n", i, x1, y1);
g2.fill(new Ellipse2D.Double(x1 - 2, y1 - 2, 4, 4));
g2.drawString(String.valueOf(i), (float) x1 + 3, (float) y1 - 3);
}
// Draw extreme data values.
g2.setPaint(Color.black);
Font font = g2.getFont();
FontRenderContext frc = g2.getFontRenderContext();
LineMetrics lm = font.getLineMetrics("0", frc);
String s = String.format("%.1f", xMin);
float width = (float) font.getStringBounds(s, frc).getWidth();
double x = offset.x + xScale * xMin;
g2.drawString(s, (float) x, (float) origin.y + lm.getAscent());
s = String.format("%.1f", xMax);
width = (float) font.getStringBounds(s, frc).getWidth();
x = offset.x + xScale * xMax;
g2.drawString(s, (float) x - width, (float) origin.y + lm.getAscent());
s = String.format("%.1f", yMin);
width = (float) font.getStringBounds(s, frc).getWidth();
double y = offset.y + yScale * yMin;
g2.drawString(s, (float) origin.x + 1, (float) y + lm.getAscent());
s = String.format("%.1f", yMax);
width = (float) font.getStringBounds(s, frc).getWidth();
y = offset.y + yScale * yMax;
g2.drawString(s, (float) origin.x + 1, (float) y);
if (firstTime) System.out.println("------------------------------");
firstTime = false;
}