JavaFX 中的嵌套 PathTransitions
Nested PathTransitions in JavaFX
我试图让我的节点沿着一个圆的路径行进，同时让那个圆沿着一个矩形的路径行进。可能吗？
这是我目前拥有的：
void move(GamePane aThis)
{
double speed = 10;
Rectangle rectangle = new Rectangle(100, 200, 100, 500);
Circle circle = new Circle(50);
circle.setFill(Color.WHITE);
circle.setStroke(Color.BLACK);
circle.setStrokeWidth(3);
PathTransition pt = new PathTransition();
pt.setDuration(Duration.millis(1000));
pt.setPath(circle);
pt.setNode(this);
pt.setOrientation(PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT);
pt.setCycleCount(Timeline.INDEFINITE);
pt.setAutoReverse(false);
pt.play();
PathTransition pt2 = new PathTransition();
pt2.setDuration(Duration.millis(1000));
pt2.setPath(rectangle);
pt2.setNode(circle);
pt2.setOrientation
(PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT);
pt2.setCycleCount(Timeline.INDEFINITE);
pt2.setAutoReverse(false);
pt2.play();
}
理论上应该可以将一个转换嵌套在另一个转换之上。
但是有一个问题：转换应用于翻译属性，而节点布局没有被修改。对于您的情况，这意味着圆将遵循矩形定义的路径，但您的节点将继续在圆的初始位置上旋转。
所以我们需要想办法在任何时刻更新圆的位置，这样节点就可以在那个位置旋转。
基于这个，一种可能的方法是使用两个AnimationTimer，以及一种在任何时刻插入路径并相应地更新位置的方法。
第一步是将原始路径转换为仅使用线性元素的路径：
import java.util.ArrayList;
import java.util.List;
import java.util.stream.IntStream;
import javafx.geometry.Point2D;
import javafx.scene.shape.ClosePath;
import javafx.scene.shape.CubicCurveTo;
import javafx.scene.shape.LineTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;
import javafx.scene.shape.PathElement;
import javafx.scene.shape.QuadCurveTo;
/**
*
* @author jpereda
*/
public class LinearPath {
private final Path originalPath;
public LinearPath(Path path){
this.originalPath=path;
}
public Path generateLinePath(){
/*
Generate a list of points interpolating the original path
*/
originalPath.getElements().forEach(this::getPoints);
/*
Create a path only with MoveTo,LineTo
*/
Path path = new Path(new MoveTo(list.get(0).getX(),list.get(0).getY()));
list.stream().skip(1).forEach(p->path.getElements().add(new LineTo(p.getX(),p.getY())));
path.getElements().add(new ClosePath());
return path;
}
private Point2D p0;
private List<Point2D> list;
private final int POINTS_CURVE=5;
private void getPoints(PathElement elem){
if(elem instanceof MoveTo){
list=new ArrayList<>();
p0=new Point2D(((MoveTo)elem).getX(),((MoveTo)elem).getY());
list.add(p0);
} else if(elem instanceof LineTo){
list.add(new Point2D(((LineTo)elem).getX(),((LineTo)elem).getY()));
} else if(elem instanceof CubicCurveTo){
Point2D ini = (list.size()>0?list.get(list.size()-1):p0);
IntStream.rangeClosed(1, POINTS_CURVE).forEach(i->list.add(evalCubicBezier((CubicCurveTo)elem, ini, ((double)i)/POINTS_CURVE)));
} else if(elem instanceof QuadCurveTo){
Point2D ini = (list.size()>0?list.get(list.size()-1):p0);
IntStream.rangeClosed(1, POINTS_CURVE).forEach(i->list.add(evalQuadBezier((QuadCurveTo)elem, ini, ((double)i)/POINTS_CURVE)));
} else if(elem instanceof ClosePath){
list.add(p0);
}
}
private Point2D evalCubicBezier(CubicCurveTo c, Point2D ini, double t){
Point2D p=new Point2D(Math.pow(1-t,3)*ini.getX()+
3*t*Math.pow(1-t,2)*c.getControlX1()+
3*(1-t)*t*t*c.getControlX2()+
Math.pow(t, 3)*c.getX(),
Math.pow(1-t,3)*ini.getY()+
3*t*Math.pow(1-t, 2)*c.getControlY1()+
3*(1-t)*t*t*c.getControlY2()+
Math.pow(t, 3)*c.getY());
return p;
}
private Point2D evalQuadBezier(QuadCurveTo c, Point2D ini, double t){
Point2D p=new Point2D(Math.pow(1-t,2)*ini.getX()+
2*(1-t)*t*c.getControlX()+
Math.pow(t, 2)*c.getX(),
Math.pow(1-t,2)*ini.getY()+
2*(1-t)*t*c.getControlY()+
Math.pow(t, 2)*c.getY());
return p;
}
}
现在，基于 javafx.animation.PathTransition.Segment 内部 class，并删除所有私有或弃用的 API，此 class 允许 public interpolator 方法，有或没有翻译：
import java.util.ArrayList;
import javafx.geometry.Bounds;
import javafx.scene.Node;
import javafx.scene.shape.ClosePath;
import javafx.scene.shape.LineTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;
/**
* Based on javafx.animation.PathTransition
*
* @author jpereda
*/
public class PathInterpolator {
private final Path originalPath;
private final Node node;
private double totalLength = 0;
private static final int SMOOTH_ZONE = 10;
private final ArrayList<Segment> segments = new ArrayList<>();
private Segment moveToSeg = Segment.getZeroSegment();
private Segment lastSeg = Segment.getZeroSegment();
public PathInterpolator(Path path, Node node){
this.originalPath=path;
this.node=node;
calculateSegments();
}
public PathInterpolator(Shape shape, Node node){
this.originalPath=(Path)Shape.subtract(shape, new Rectangle(0,0));
this.node=node;
calculateSegments();
}
private void calculateSegments() {
segments.clear();
Path linePath = new LinearPath(originalPath).generateLinePath();
linePath.getElements().forEach(elem->{
Segment newSeg = null;
if(elem instanceof MoveTo){
moveToSeg = Segment.newMoveTo(((MoveTo)elem).getX(),((MoveTo)elem).getY(), lastSeg.accumLength);
newSeg = moveToSeg;
} else if(elem instanceof LineTo){
newSeg = Segment.newLineTo(lastSeg, ((LineTo)elem).getX(),((LineTo)elem).getY());
} else if(elem instanceof ClosePath){
newSeg = Segment.newClosePath(lastSeg, moveToSeg);
if (newSeg == null) {
lastSeg.convertToClosePath(moveToSeg);
}
}
if (newSeg != null) {
segments.add(newSeg);
lastSeg = newSeg;
}
});
totalLength = lastSeg.accumLength;
}
public void interpolate(double frac) {
interpolate(frac,0,0);
}
public void interpolate(double frac, double translateX, double translateY) {
double part = totalLength * Math.min(1, Math.max(0, frac));
int segIdx = findSegment(0, segments.size() - 1, part);
Segment seg = segments.get(segIdx);
double lengthBefore = seg.accumLength - seg.length;
double partLength = part - lengthBefore;
double ratio = partLength / seg.length;
Segment prevSeg = seg.prevSeg;
double x = prevSeg.toX + (seg.toX - prevSeg.toX) * ratio;
double y = prevSeg.toY + (seg.toY - prevSeg.toY) * ratio;
double rotateAngle = seg.rotateAngle;
// provide smooth rotation on segment bounds
double z = Math.min(SMOOTH_ZONE, seg.length / 2);
if (partLength < z && !prevSeg.isMoveTo) {
//interpolate rotation to previous segment
rotateAngle = interpolateAngle(
prevSeg.rotateAngle, seg.rotateAngle,
partLength / z / 2 + 0.5F);
} else {
double dist = seg.length - partLength;
Segment nextSeg = seg.nextSeg;
if (dist < z && nextSeg != null) {
//interpolate rotation to next segment
if (!nextSeg.isMoveTo) {
rotateAngle = interpolateAngle(
seg.rotateAngle, nextSeg.rotateAngle,
(z - dist) / z / 2);
}
}
}
node.setTranslateX(x - getPivotX() + translateX);
node.setTranslateY(y - getPivotY() + translateY);
node.setRotate(rotateAngle);
}
private double getPivotX() {
final Bounds bounds = node.getLayoutBounds();
return bounds.getMinX() + bounds.getWidth()/2;
}
private double getPivotY() {
final Bounds bounds = node.getLayoutBounds();
return bounds.getMinY() + bounds.getHeight()/2;
}
/**
* Returns the index of the first segment having accumulated length
* from the path beginning, greater than {@code length}
*/
private int findSegment(int begin, int end, double length) {
// check for search termination
if (begin == end) {
// find last non-moveTo segment for given length
return segments.get(begin).isMoveTo && begin > 0
? findSegment(begin - 1, begin - 1, length)
: begin;
}
// otherwise continue binary search
int middle = begin + (end - begin) / 2;
return segments.get(middle).accumLength > length
? findSegment(begin, middle, length)
: findSegment(middle + 1, end, length);
}
/** Interpolates angle according to rate,
* with correct 0->360 and 360->0 transitions
*/
private static double interpolateAngle(double fromAngle, double toAngle, double ratio) {
double delta = toAngle - fromAngle;
if (Math.abs(delta) > 180) {
toAngle += delta > 0 ? -360 : 360;
}
return normalize(fromAngle + ratio * (toAngle - fromAngle));
}
/** Converts angle to range 0-360
*/
private static double normalize(double angle) {
while (angle > 360) {
angle -= 360;
}
while (angle < 0) {
angle += 360;
}
return angle;
}
private static class Segment {
private static final Segment zeroSegment = new Segment(true, 0, 0, 0, 0, 0);
boolean isMoveTo;
double length;
// total length from the path's beginning to the end of this segment
double accumLength;
// end point of this segment
double toX;
double toY;
// segment's rotation angle in degrees
double rotateAngle;
Segment prevSeg;
Segment nextSeg;
private Segment(boolean isMoveTo, double toX, double toY,
double length, double lengthBefore, double rotateAngle) {
this.isMoveTo = isMoveTo;
this.toX = toX;
this.toY = toY;
this.length = length;
this.accumLength = lengthBefore + length;
this.rotateAngle = rotateAngle;
}
public static Segment getZeroSegment() {
return zeroSegment;
}
public static Segment newMoveTo(double toX, double toY,
double accumLength) {
return new Segment(true, toX, toY, 0, accumLength, 0);
}
public static Segment newLineTo(Segment fromSeg, double toX, double toY) {
double deltaX = toX - fromSeg.toX;
double deltaY = toY - fromSeg.toY;
double length = Math.sqrt((deltaX * deltaX) + (deltaY * deltaY));
if ((length >= 1) || fromSeg.isMoveTo) { // filtering out flattening noise
double sign = Math.signum(deltaY == 0 ? deltaX : deltaY);
double angle = (sign * Math.acos(deltaX / length));
angle = normalize(angle / Math.PI * 180);
Segment newSeg = new Segment(false, toX, toY,
length, fromSeg.accumLength, angle);
fromSeg.nextSeg = newSeg;
newSeg.prevSeg = fromSeg;
return newSeg;
}
return null;
}
public static Segment newClosePath(Segment fromSeg, Segment moveToSeg) {
Segment newSeg = newLineTo(fromSeg, moveToSeg.toX, moveToSeg.toY);
if (newSeg != null) {
newSeg.convertToClosePath(moveToSeg);
}
return newSeg;
}
public void convertToClosePath(Segment moveToSeg) {
Segment firstLineToSeg = moveToSeg.nextSeg;
nextSeg = firstLineToSeg;
firstLineToSeg.prevSeg = this;
}
}
}
基本上，一旦有了线性路径，它就会为每一行生成一个 Segment。现在有了这些段的列表，您可以调用 interpolate 方法来计算节点在 0 和 1 之间的任何分数的位置和旋转，并且在第二次转换的情况下，相应地更新形状的位置.
最后，您可以在应用程序中创建两个 AnimationTimer：
@Override
public void start(Stage primaryStage) {
Pane root = new Pane();
Polygon poly = new Polygon( 0, 0, 30, 15, 0, 30);
poly.setFill(Color.YELLOW);
poly.setStroke(Color.RED);
root.getChildren().add(poly);
Rectangle rectangle = new Rectangle(200, 100, 100, 400);
rectangle.setFill(Color.TRANSPARENT);
rectangle.setStroke(Color.BLUE);
Circle circle = new Circle(50);
circle.setFill(Color.TRANSPARENT);
circle.setStroke(Color.RED);
circle.setStrokeWidth(3);
root.getChildren().add(rectangle);
root.getChildren().add(circle);
PathInterpolator in1=new PathInterpolator(rectangle, circle);
PathInterpolator in2=new PathInterpolator(circle, poly);
AnimationTimer timer1 = new AnimationTimer() {
@Override
public void handle(long now) {
double millis=(now/1_000_000)%10000;
in1.interpolate(millis/10000);
}
};
AnimationTimer timer2 = new AnimationTimer() {
@Override
public void handle(long now) {
double millis=(now/1_000_000)%2000;
// Interpolate over the translated circle
in2.interpolate(millis/2000,
circle.getTranslateX(),
circle.getTranslateY());
}
};
timer2.start();
timer1.start();
Scene scene = new Scene(root, 800, 600);
primaryStage.setScene(scene);
primaryStage.show();
}
请注意，您可以对动画应用不同的速度。
这张照片拍摄了这个动画的两个瞬间。
我试图让我的节点沿着一个圆的路径行进，同时让那个圆沿着一个矩形的路径行进。可能吗？
这是我目前拥有的：
void move(GamePane aThis)
{
double speed = 10;
Rectangle rectangle = new Rectangle(100, 200, 100, 500);
Circle circle = new Circle(50);
circle.setFill(Color.WHITE);
circle.setStroke(Color.BLACK);
circle.setStrokeWidth(3);
PathTransition pt = new PathTransition();
pt.setDuration(Duration.millis(1000));
pt.setPath(circle);
pt.setNode(this);
pt.setOrientation(PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT);
pt.setCycleCount(Timeline.INDEFINITE);
pt.setAutoReverse(false);
pt.play();
PathTransition pt2 = new PathTransition();
pt2.setDuration(Duration.millis(1000));
pt2.setPath(rectangle);
pt2.setNode(circle);
pt2.setOrientation
(PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT);
pt2.setCycleCount(Timeline.INDEFINITE);
pt2.setAutoReverse(false);
pt2.play();
}
理论上应该可以将一个转换嵌套在另一个转换之上。
但是有一个问题：转换应用于翻译属性，而节点布局没有被修改。对于您的情况，这意味着圆将遵循矩形定义的路径，但您的节点将继续在圆的初始位置上旋转。
所以我们需要想办法在任何时刻更新圆的位置，这样节点就可以在那个位置旋转。
基于这个AnimationTimer，以及一种在任何时刻插入路径并相应地更新位置的方法。
第一步是将原始路径转换为仅使用线性元素的路径：
import java.util.ArrayList;
import java.util.List;
import java.util.stream.IntStream;
import javafx.geometry.Point2D;
import javafx.scene.shape.ClosePath;
import javafx.scene.shape.CubicCurveTo;
import javafx.scene.shape.LineTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;
import javafx.scene.shape.PathElement;
import javafx.scene.shape.QuadCurveTo;
/**
*
* @author jpereda
*/
public class LinearPath {
private final Path originalPath;
public LinearPath(Path path){
this.originalPath=path;
}
public Path generateLinePath(){
/*
Generate a list of points interpolating the original path
*/
originalPath.getElements().forEach(this::getPoints);
/*
Create a path only with MoveTo,LineTo
*/
Path path = new Path(new MoveTo(list.get(0).getX(),list.get(0).getY()));
list.stream().skip(1).forEach(p->path.getElements().add(new LineTo(p.getX(),p.getY())));
path.getElements().add(new ClosePath());
return path;
}
private Point2D p0;
private List<Point2D> list;
private final int POINTS_CURVE=5;
private void getPoints(PathElement elem){
if(elem instanceof MoveTo){
list=new ArrayList<>();
p0=new Point2D(((MoveTo)elem).getX(),((MoveTo)elem).getY());
list.add(p0);
} else if(elem instanceof LineTo){
list.add(new Point2D(((LineTo)elem).getX(),((LineTo)elem).getY()));
} else if(elem instanceof CubicCurveTo){
Point2D ini = (list.size()>0?list.get(list.size()-1):p0);
IntStream.rangeClosed(1, POINTS_CURVE).forEach(i->list.add(evalCubicBezier((CubicCurveTo)elem, ini, ((double)i)/POINTS_CURVE)));
} else if(elem instanceof QuadCurveTo){
Point2D ini = (list.size()>0?list.get(list.size()-1):p0);
IntStream.rangeClosed(1, POINTS_CURVE).forEach(i->list.add(evalQuadBezier((QuadCurveTo)elem, ini, ((double)i)/POINTS_CURVE)));
} else if(elem instanceof ClosePath){
list.add(p0);
}
}
private Point2D evalCubicBezier(CubicCurveTo c, Point2D ini, double t){
Point2D p=new Point2D(Math.pow(1-t,3)*ini.getX()+
3*t*Math.pow(1-t,2)*c.getControlX1()+
3*(1-t)*t*t*c.getControlX2()+
Math.pow(t, 3)*c.getX(),
Math.pow(1-t,3)*ini.getY()+
3*t*Math.pow(1-t, 2)*c.getControlY1()+
3*(1-t)*t*t*c.getControlY2()+
Math.pow(t, 3)*c.getY());
return p;
}
private Point2D evalQuadBezier(QuadCurveTo c, Point2D ini, double t){
Point2D p=new Point2D(Math.pow(1-t,2)*ini.getX()+
2*(1-t)*t*c.getControlX()+
Math.pow(t, 2)*c.getX(),
Math.pow(1-t,2)*ini.getY()+
2*(1-t)*t*c.getControlY()+
Math.pow(t, 2)*c.getY());
return p;
}
}
现在，基于 javafx.animation.PathTransition.Segment 内部 class，并删除所有私有或弃用的 API，此 class 允许 public interpolator 方法，有或没有翻译：
import java.util.ArrayList;
import javafx.geometry.Bounds;
import javafx.scene.Node;
import javafx.scene.shape.ClosePath;
import javafx.scene.shape.LineTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;
/**
* Based on javafx.animation.PathTransition
*
* @author jpereda
*/
public class PathInterpolator {
private final Path originalPath;
private final Node node;
private double totalLength = 0;
private static final int SMOOTH_ZONE = 10;
private final ArrayList<Segment> segments = new ArrayList<>();
private Segment moveToSeg = Segment.getZeroSegment();
private Segment lastSeg = Segment.getZeroSegment();
public PathInterpolator(Path path, Node node){
this.originalPath=path;
this.node=node;
calculateSegments();
}
public PathInterpolator(Shape shape, Node node){
this.originalPath=(Path)Shape.subtract(shape, new Rectangle(0,0));
this.node=node;
calculateSegments();
}
private void calculateSegments() {
segments.clear();
Path linePath = new LinearPath(originalPath).generateLinePath();
linePath.getElements().forEach(elem->{
Segment newSeg = null;
if(elem instanceof MoveTo){
moveToSeg = Segment.newMoveTo(((MoveTo)elem).getX(),((MoveTo)elem).getY(), lastSeg.accumLength);
newSeg = moveToSeg;
} else if(elem instanceof LineTo){
newSeg = Segment.newLineTo(lastSeg, ((LineTo)elem).getX(),((LineTo)elem).getY());
} else if(elem instanceof ClosePath){
newSeg = Segment.newClosePath(lastSeg, moveToSeg);
if (newSeg == null) {
lastSeg.convertToClosePath(moveToSeg);
}
}
if (newSeg != null) {
segments.add(newSeg);
lastSeg = newSeg;
}
});
totalLength = lastSeg.accumLength;
}
public void interpolate(double frac) {
interpolate(frac,0,0);
}
public void interpolate(double frac, double translateX, double translateY) {
double part = totalLength * Math.min(1, Math.max(0, frac));
int segIdx = findSegment(0, segments.size() - 1, part);
Segment seg = segments.get(segIdx);
double lengthBefore = seg.accumLength - seg.length;
double partLength = part - lengthBefore;
double ratio = partLength / seg.length;
Segment prevSeg = seg.prevSeg;
double x = prevSeg.toX + (seg.toX - prevSeg.toX) * ratio;
double y = prevSeg.toY + (seg.toY - prevSeg.toY) * ratio;
double rotateAngle = seg.rotateAngle;
// provide smooth rotation on segment bounds
double z = Math.min(SMOOTH_ZONE, seg.length / 2);
if (partLength < z && !prevSeg.isMoveTo) {
//interpolate rotation to previous segment
rotateAngle = interpolateAngle(
prevSeg.rotateAngle, seg.rotateAngle,
partLength / z / 2 + 0.5F);
} else {
double dist = seg.length - partLength;
Segment nextSeg = seg.nextSeg;
if (dist < z && nextSeg != null) {
//interpolate rotation to next segment
if (!nextSeg.isMoveTo) {
rotateAngle = interpolateAngle(
seg.rotateAngle, nextSeg.rotateAngle,
(z - dist) / z / 2);
}
}
}
node.setTranslateX(x - getPivotX() + translateX);
node.setTranslateY(y - getPivotY() + translateY);
node.setRotate(rotateAngle);
}
private double getPivotX() {
final Bounds bounds = node.getLayoutBounds();
return bounds.getMinX() + bounds.getWidth()/2;
}
private double getPivotY() {
final Bounds bounds = node.getLayoutBounds();
return bounds.getMinY() + bounds.getHeight()/2;
}
/**
* Returns the index of the first segment having accumulated length
* from the path beginning, greater than {@code length}
*/
private int findSegment(int begin, int end, double length) {
// check for search termination
if (begin == end) {
// find last non-moveTo segment for given length
return segments.get(begin).isMoveTo && begin > 0
? findSegment(begin - 1, begin - 1, length)
: begin;
}
// otherwise continue binary search
int middle = begin + (end - begin) / 2;
return segments.get(middle).accumLength > length
? findSegment(begin, middle, length)
: findSegment(middle + 1, end, length);
}
/** Interpolates angle according to rate,
* with correct 0->360 and 360->0 transitions
*/
private static double interpolateAngle(double fromAngle, double toAngle, double ratio) {
double delta = toAngle - fromAngle;
if (Math.abs(delta) > 180) {
toAngle += delta > 0 ? -360 : 360;
}
return normalize(fromAngle + ratio * (toAngle - fromAngle));
}
/** Converts angle to range 0-360
*/
private static double normalize(double angle) {
while (angle > 360) {
angle -= 360;
}
while (angle < 0) {
angle += 360;
}
return angle;
}
private static class Segment {
private static final Segment zeroSegment = new Segment(true, 0, 0, 0, 0, 0);
boolean isMoveTo;
double length;
// total length from the path's beginning to the end of this segment
double accumLength;
// end point of this segment
double toX;
double toY;
// segment's rotation angle in degrees
double rotateAngle;
Segment prevSeg;
Segment nextSeg;
private Segment(boolean isMoveTo, double toX, double toY,
double length, double lengthBefore, double rotateAngle) {
this.isMoveTo = isMoveTo;
this.toX = toX;
this.toY = toY;
this.length = length;
this.accumLength = lengthBefore + length;
this.rotateAngle = rotateAngle;
}
public static Segment getZeroSegment() {
return zeroSegment;
}
public static Segment newMoveTo(double toX, double toY,
double accumLength) {
return new Segment(true, toX, toY, 0, accumLength, 0);
}
public static Segment newLineTo(Segment fromSeg, double toX, double toY) {
double deltaX = toX - fromSeg.toX;
double deltaY = toY - fromSeg.toY;
double length = Math.sqrt((deltaX * deltaX) + (deltaY * deltaY));
if ((length >= 1) || fromSeg.isMoveTo) { // filtering out flattening noise
double sign = Math.signum(deltaY == 0 ? deltaX : deltaY);
double angle = (sign * Math.acos(deltaX / length));
angle = normalize(angle / Math.PI * 180);
Segment newSeg = new Segment(false, toX, toY,
length, fromSeg.accumLength, angle);
fromSeg.nextSeg = newSeg;
newSeg.prevSeg = fromSeg;
return newSeg;
}
return null;
}
public static Segment newClosePath(Segment fromSeg, Segment moveToSeg) {
Segment newSeg = newLineTo(fromSeg, moveToSeg.toX, moveToSeg.toY);
if (newSeg != null) {
newSeg.convertToClosePath(moveToSeg);
}
return newSeg;
}
public void convertToClosePath(Segment moveToSeg) {
Segment firstLineToSeg = moveToSeg.nextSeg;
nextSeg = firstLineToSeg;
firstLineToSeg.prevSeg = this;
}
}
}
基本上，一旦有了线性路径，它就会为每一行生成一个 Segment。现在有了这些段的列表，您可以调用 interpolate 方法来计算节点在 0 和 1 之间的任何分数的位置和旋转，并且在第二次转换的情况下，相应地更新形状的位置.
最后，您可以在应用程序中创建两个 AnimationTimer：
@Override
public void start(Stage primaryStage) {
Pane root = new Pane();
Polygon poly = new Polygon( 0, 0, 30, 15, 0, 30);
poly.setFill(Color.YELLOW);
poly.setStroke(Color.RED);
root.getChildren().add(poly);
Rectangle rectangle = new Rectangle(200, 100, 100, 400);
rectangle.setFill(Color.TRANSPARENT);
rectangle.setStroke(Color.BLUE);
Circle circle = new Circle(50);
circle.setFill(Color.TRANSPARENT);
circle.setStroke(Color.RED);
circle.setStrokeWidth(3);
root.getChildren().add(rectangle);
root.getChildren().add(circle);
PathInterpolator in1=new PathInterpolator(rectangle, circle);
PathInterpolator in2=new PathInterpolator(circle, poly);
AnimationTimer timer1 = new AnimationTimer() {
@Override
public void handle(long now) {
double millis=(now/1_000_000)%10000;
in1.interpolate(millis/10000);
}
};
AnimationTimer timer2 = new AnimationTimer() {
@Override
public void handle(long now) {
double millis=(now/1_000_000)%2000;
// Interpolate over the translated circle
in2.interpolate(millis/2000,
circle.getTranslateX(),
circle.getTranslateY());
}
};
timer2.start();
timer1.start();
Scene scene = new Scene(root, 800, 600);
primaryStage.setScene(scene);
primaryStage.show();
}
请注意，您可以对动画应用不同的速度。
这张照片拍摄了这个动画的两个瞬间。