protected List<Position> computePathPositions(
Position startPosition, Position endPosition, Angle delta) {
Angle dist = LatLon.greatCircleDistance(startPosition, endPosition);
dist = dist.multiply(0.6);
Angle azimuth = LatLon.greatCircleAzimuth(startPosition, endPosition);
LatLon locA = LatLon.greatCircleEndPosition(startPosition, azimuth.add(delta), dist);
dist = dist.multiply(0.9);
LatLon locB = LatLon.greatCircleEndPosition(startPosition, azimuth.subtract(delta), dist);
return Arrays.asList(startPosition, new Position(locA, 0), new Position(locB, 0), endPosition);
}
/**
* Create the list of positions that describe the arrow.
*
* @param dc Current draw context.
*/
protected void createShapes(DrawContext dc) {
this.paths = new Path[2];
int i = 0;
Angle azimuth1 = LatLon.greatCircleAzimuth(this.position1, this.position2);
Angle azimuth2 = LatLon.greatCircleAzimuth(this.position1, this.position3);
Angle delta = azimuth2.subtract(azimuth1);
int sign = delta.degrees > 0 ? 1 : -1;
delta = Angle.fromDegrees(sign * 5.0);
// Create a path for the line part of the arrow
List<Position> positions = this.computePathPositions(this.position1, this.position2, delta);
this.paths[i++] = this.createPath(positions);
// Create a polygon to draw the arrow head.
double arrowLength = this.getArrowLength();
Angle arrowAngle = this.getArrowAngle();
positions =
this.computeArrowheadPositions(
dc, positions.get(2), positions.get(3), arrowLength, arrowAngle);
this.arrowHead1 = this.createPolygon(positions);
this.arrowHead1.setLocations(positions);
delta = delta.multiply(-1.0);
positions = this.computePathPositions(this.position1, this.position3, delta);
this.paths[i] = this.createPath(positions);
positions =
this.computeArrowheadPositions(
dc, positions.get(2), positions.get(3), arrowLength, arrowAngle);
this.arrowHead2 = this.createPolygon(positions);
this.arrowHead2.setLocations(positions);
}