boolean layout(PointLabel label, LabelIndex labels) {
String text = label.getText();
Feature f = label.getFeature();
Geometry g = label.getGeometry();
Rule rule = label.getRule();
// get center in screen space
Coordinate centroid = g.getCentroid().getCoordinate();
PointF anchor = tx.getWorldToCanvas().map(centroid);
// apply offsets
anchor.x += rule.number(f, TEXT_DX, 0f);
anchor.y += rule.number(f, TEXT_DY, 0f);
Paint p = label.get(Paint.class, Paint.class);
// compute bounds of this label
Rect b = new Rect();
p.getTextBounds(text, 0, text.length(), b);
// padding
float padding = rule.number(f, TEXT_MIN_PADDING, 0f);
if (padding > 0f) {
b = expand(b, padding);
}
// label.setAnchor(new Coordinate(center.x,center.y));
// label.setBox(envelope(rectFromBottomLeft(center, b.width(), b.height())));
RectF c = new RectF(b);
tx.getCanvasToWorld().mapRect(c);
centroid = tx.getCanvasToWorld().map(anchor);
label.setAnchor(centroid);
RectF box = null;
switch (p.getTextAlign()) {
case LEFT:
box = rectFromBottomLeft(point(centroid), c.width(), c.height());
break;
case CENTER:
box = rectFromBottomCenter(point(centroid), c.width(), c.height());
break;
case RIGHT:
box = rectFromBottomRight(point(centroid), c.width(), c.height());
break;
}
label.setBox(envelope(box));
return labels.insert(label);
}
boolean layout(LineLabel label, LabelIndex labels) {
String txt = label.getText();
Rule rule = label.getRule();
Feature f = label.getFeature();
Geometry g = label.getGeometry();
LineString line = null;
if (g instanceof MultiLineString) {
// TODO: handle multiple lines
if (g.getNumGeometries() == 1) {
line = (LineString) g.getGeometryN(0);
}
} else {
line = (LineString) g;
}
if (line == null) {
return false;
}
Paint p = label.get(Paint.class, Paint.class);
// compute the bounds of the label with no rotation
Rect r = new Rect();
p.getTextBounds(txt, 0, txt.length(), r);
// map it to world coordinates
RectF bounds = new RectF(r);
tx.getCanvasToWorld().mapRect(bounds);
// ignore label if its too long for the line
if (line.getLength() < bounds.width()) {
// ignore this label
return false;
}
// reverse
if (line.getPointN(0).getX() > line.getPointN(line.getNumPoints() - 1).getX()) {
line = (LineString) line.reverse();
}
// compute width of individual letters
float[] widths = new float[txt.length()];
p.getTextWidths(txt, widths);
// map the widths to world space
float sum = 0;
for (int i = 0; i < widths.length; i++) {
RectF s = new RectF(0, 0, widths[i], 1);
tx.getCanvasToWorld().mapRect(s);
widths[i] = s.width();
sum += s.width();
}
// TODO: properly figure out spacing between letters
float space = tx.getCanvasToWorld().mapRadius(1);
// allowable angle change in consecutive characters
double maxAngleDelta = rule.number(f, TEXT_MAX_CHAR_ANGLE_DELTA, DEFAULT_MAX_ANGLE_CHAR_DELTA);
//
// sample points along the line for letters
//
List<LineSegment> path = new ArrayList<LineSegment>();
LineSampler sampler = new LineSampler(line.getCoordinates());
for (int i = 0; i < txt.length(); i++) {
// get next point
Coordinate c1 = sampler.sample();
// advance by width of letter
sampler.advance(widths[i]);
// get point for end of letter
Coordinate c2 = sampler.sample();
if (c1 == null || c2 == null) {
// ran out of room
return false;
}
LineSegment seg = new LineSegment(c1, c2);
// check angle made with previous segment
if (i > 0) {
LineSegment prev = path.get(i - 1);
if (Math.abs(angle(seg) - angle(prev)) > maxAngleDelta) {
return false;
}
}
path.add(seg);
sampler.advance(space);
}
label.setPath(path);
label.setShape(toShape(path, bounds.height()));
return labels.insert(label);
}