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2022/08/31

Use AffineTransform to place Roman numerals on an analog clock face

Code

private final String[] arabicNumerals = {
  "12", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11"
};
private final String[] romanNumerals = {
  "XII", "I", "II", "III", "IIII", "V", "VI", "VII", "VIII", "IX", "X", "XI"
};

private void paintClockNumbers(
    Graphics2D g2, double radius, double hourMarkerLen) {
  AffineTransform at = AffineTransform.getRotateInstance(0d);
  g2.setColor(Color.WHITE);
  Font font = g2.getFont();
  FontRenderContext frc = g2.getFontRenderContext();
  if (isRomanNumerals) {
    AffineTransform si = AffineTransform.getScaleInstance(1d, 2d);
    for (String txt : romanNumerals) {
      Shape s = getTextLayout(txt, font, frc).getOutline(si);
      Rectangle2D r = s.getBounds2D();
      double tx = r.getCenterX();
      double ty = radius - hourMarkerLen - r.getHeight() + r.getCenterY() * .5;
      Shape t = AffineTransform.getTranslateInstance(-tx, -ty)
                               .createTransformedShape(s);
      g2.fill(at.createTransformedShape(t));
      at.rotate(Math.PI / 6d);
    }
  } else {
    Point2D ptSrc = new Point2D.Double();
    for (String txt : arabicNumerals) {
      Shape s = getTextLayout(txt, font, frc).getOutline(null);
      Rectangle2D r = s.getBounds2D();
      double ty = radius - hourMarkerLen - r.getHeight() - r.getCenterY() * .5;
      ptSrc.setLocation(0d, -ty);
      Point2D pt = at.transform(ptSrc, null);
      double dx = pt.getX() - r.getCenterX();
      double dy = pt.getY() - r.getCenterY();
      // g2.drawString(txt, (float) dx, (float) dy);
      g2.fill(AffineTransform.getTranslateInstance(dx, dy)
        .createTransformedShape(s));
      at.rotate(Math.PI / 6d);
    }
  }
}

private static TextLayout getTextLayout(
    String txt, Font font, FontRenderContext frc) {
  return new TextLayout(txt, font, frc);
}

References