Exploring Iterated Function Systems

paintgrid.java

// Transform unit square to view space
double x0 = centre.getX() - (size.getWidth() / 2d / scale);
double y0 = centre.getY() - (size.getHeight() / 2d / scale);
AffineTransform view = AffineTransform.getScaleInstance(scale, scale);
view.translate(-x0, -y0);

// Calculate grid position
double spacing = config.getMaxGrid() / scale;
double mx = centre.getX() - (size.getWidth() / 2d / scale) - (size.getWidth() / 2d);
double my = centre.getY() - (size.getHeight() / 2d / scale) - (size.getHeight() / 2d);
double rx = Math.IEEEremainder(mx, spacing);
double ry = Math.IEEEremainder(my, spacing);
double sx = mx - rx + (size.getWidth() / 2d);
double sy = my - ry + (size.getHeight() / 2d);
int xn = (int) ((sx - x0) / spacing);
int yn = (int) ((sy - y0) / spacing);
double x1 = sx + (xn - 2) * spacing;
double y1 = sy + (yn - 2) * spacing;
int n = (size.width / config.getMaxGrid()) + 4;

// Draw grid lines
g.setStroke(DASHED_LINE_1);
for (int i = 0; i < n; i++) {
  double x = x1 + i * spacing;
  if (DoubleMath.fuzzyEquals(x, size.getWidth() / 2d, spacing / 100d)) {
    g.setPaint(alpha(config.getRender().getForeground(), 128));
  } else {
    g.setPaint(alpha(config.getRender().getForeground(), 64));
  }
  double pts[] = { x, y1, x, y1 + n * spacing };
  view.transform(pts, 0, pts, 0, 2);
  if (pts[0] > 0d && pts[0] < size.getWidth()) {
    Line2D line = new Line2D.Double(pts[0], pts[1], pts[2], pts[3]);
    g.draw(line);
  }
}
for (int i = 0; i < n; i++) {
  double y = y1 + i * spacing;
  if (DoubleMath.fuzzyEquals(y, size.getHeight() / 2d, spacing / 100d)) {
    g.setPaint(alpha(config.getRender().getForeground(), 128));
  } else {
    g.setPaint(alpha(config.getRender().getForeground(), 64));
  }
  double pts[] = { x1, y, x1 + n * spacing, y };
  view.transform(pts, 0, pts, 0, 2);
  if (pts[1] > 0d && pts[1] < size.getWidth()) {
    Line2D line = new Line2D.Double(pts[0], pts[1], pts[2], pts[3]);
    g.draw(line);
  }
}