It fetches a path from the SnakeMousePath input source and * affects the glyph that has the 'Leader' property set to true. The * leader and its siblings are then attracted to their respective * position on the path with equal distance between them.
* *The siblings are affected through the leader to minimize * computation. One way was to look at each glyph to see if * they were a sibling of a leader, then compute their position * backwards on the path. Much simpler the way it is now, find * the leader and then compute it and its right neighbours.
*/ public class FollowLeaderPath extends IWillFollowAction { // constants static final int GLYPH_SPACER = 1; static final int WORD_SPACER = 15; // mouse path input source SnakeMousePath isrcMousePath; double pathPointDistance; /** * Creates a new instance of FollowLeaderPath * * @param isrcMousePath the SnakeMousePath input source * @param pathPointDistance the minimum distance between two consecutive points on the path */ public FollowLeaderPath(SnakeMousePath isrcMousePath, double pathPointDistance) { this.isrcMousePath = isrcMousePath; this.pathPointDistance = pathPointDistance; } /** * If the TextObject is the 'Leader', moves it and its right siblings on the * path, rotating each TextObject to match the slope of the path segment it * is lying on. * * @param to the TextObject to act upon */ public ActionResult behave(TextObject to) { // get a copy of the path ArrayList path = isrcMousePath.getPath(); // if there is no path, return if (path.size() == 0) return new ActionResult(false, false, false); // if the text object is the leader then attract it and its sibling towards the path if (isLeader(to).get()) { // start at the end of the path (most recent mouse position) int pathIndex = path.size() - 1; int pathPixelDistance = 0; // distance in pixels from the end of the path where this object belongs Vector3 pathPosition; // current path position, derived from pathIndex // start at the object itself as it is the leader TextObject rightSibling = to; while (rightSibling != null) { // find the point on the path prior to the position for this object int prevPathIndex = (path.size()-1)-(int)(pathPixelDistance/pathPointDistance); if (prevPathIndex <= 0) break; // calculate the vector to the previous path point Point prevPathPoint = (Point)path.get(prevPathIndex); Vector3 prevPathVector3 = new Vector3(prevPathPoint.x, prevPathPoint.y); // calculate the vector to the next path point Point nextPathPoint = (Point)path.get(prevPathIndex - 1); Vector3 nextPathVector3 = new Vector3(nextPathPoint.x, nextPathPoint.y); // calculate the vector from the previous path point to the object's desired location on the path pathPosition = new Vector3(nextPathVector3); pathPosition.sub(prevPathVector3); pathPosition.scalar((pathPixelDistance % pathPointDistance) / pathPointDistance); pathPosition.add(prevPathVector3); // move the glyph towards the new position on the path Vector3Property position = (Vector3Property)rightSibling.getProperty("Position"); Vector3 positionAbs = rightSibling.getPositionAbsolute(); // calculate the offset from the current position Vector3 move = new Vector3(pathPosition.x - positionAbs.x, pathPosition.y - positionAbs.y); // move towards new position by a max of 20 if (move.length() > 20.0) { try { move.normalize(); move.scalar(20.0); } catch (Vector3ArithmeticException e) { System.out.println("vector 3 exception"); } } // translate position position.add(move); // find the glyph angle by calculating the slope of the points // on the path located before and after the position of the glyph NumberProperty rotation = (NumberProperty)rightSibling.getProperty("Rotation"); if (pathIndex > 0) { double rotate = 0; if (pathIndex < path.size()-1) { rotate = Math.atan2(nextPathPoint.y-prevPathPoint.y, nextPathPoint.x-prevPathPoint.x); } else if (pathIndex == path.size()-1) { rotate = Math.atan2(prevPathPoint.y-nextPathPoint.y, prevPathPoint.x-nextPathPoint.x); } // limit the rotations to the 1st and 4th quadrants // so that the glyphs are always readable if (rotate < 0) rotate += Math.PI*2; if ((rotate < Math.PI/2*3) && (rotate > Math.PI/2)) rotate += Math.PI; if (rotate > Math.PI*2) rotate -= Math.PI*2; rotation.set(rotate); } // if we are moving from right to left, set the offset for the next object based on the current object's width if (nextPathVector3.x >= prevPathVector3.x) { pathPixelDistance += GLYPH_SPACER + ((TextObjectGlyph) rightSibling).getLogicalBounds().getWidth(); } // get the next sibling if (rightSibling.getRightSibling() == null) { if (rightSibling.getParent() == null) { // no parent, we are done rightSibling = null; } else { TextObjectGroup rightParent = (TextObjectGroup)rightSibling.getParent().getRightSibling(); if (rightParent == null) { // no more words, we are done rightSibling = null; } else { // go to the first glyph of the next word rightSibling = rightParent.getLeftMostChild(); pathPixelDistance += WORD_SPACER; } } } else { // go to the next glyph of the current word rightSibling = rightSibling.getRightSibling(); } // if we are moving from left to right, set the offset for the next object based on its own width if ((rightSibling != null) && (nextPathVector3.x < prevPathVector3.x)) { pathPixelDistance += GLYPH_SPACER + ((TextObjectGlyph) rightSibling).getLogicalBounds().getWidth(); } } } return new ActionResult(false, false, false); } }