Javafx 简明教程

JavaFX - Path Transition

JavaFX 中的路径过渡用于将 JavaFX 节点（或对象）围绕特定路径移动。这类似于平移过渡，因为它也从一个位置将对象移动到另一个位置。然而，平移过渡没有提供对象移动的连续路径；而路径过渡则提供了。

任何 JavaFX 节点，如 2D 或 3D 形状、文本、图像等，都可以沿着任何路径移动：直线或曲线。

Path Transition in JavaFX

JavaFX 提供了一个 PathTransition 类来对 JavaFX 节点应用路径过渡。此类属于 javafx.animation 包。此过渡创建一个路径动画，该动画使一个对象在某个路径中移动并跨越其持续时间。

路径过渡所做的仅仅是平移一个对象以将其重新定位。沿着路径的此平移通过定期更新 X 和 Y 方向上节点的坐标以及将方向更新为 OrientationType.ORTHOGONAL_TO_TANGENT 来完成的。动画路径由任何 JavaFX 形状的轮廓定义。

PathTransition 类提供了可应用于节点的以下属性 −

Example 1

以下是演示 JavaFX 中路径过渡的程序。将此代码保存在一个名为 PathTransitionExample.java 的文件中。

import javafx.animation.PathTransition;
import javafx.application.Application;
import static javafx.application.Application.launch;

import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;

import javafx.scene.shape.Circle;
import javafx.scene.shape.CubicCurveTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;

import javafx.stage.Stage;
import javafx.util.Duration;

public class PathTransitionExample extends Application {
   @Override
   public void start(Stage stage) {
      //Drawing a Circle
      Circle circle = new Circle();

      //Setting the position of the circle
      circle.setCenterX(300.0f);
      circle.setCenterY(135.0f);

      //Setting the radius of the circle
      circle.setRadius(25.0f);

      //Setting the color of the circle
      circle.setFill(Color.BROWN);

      //Setting the stroke width of the circle
      circle.setStrokeWidth(20);

      //Instantiating the path class
      Path path = new Path();

      //Creating the MoveTo path element
      MoveTo moveTo = new MoveTo(100, 150);

      //Creating the Cubic curve path element
      CubicCurveTo cubicCurveTo = new CubicCurveTo(400, 40, 175, 250, 500, 150);

      //Adding the path elements to Observable list of the Path class
      path.getElements().add(moveTo);
      path.getElements().add(cubicCurveTo);

      //Creating a path transition
      PathTransition pathTransition = new PathTransition();

      //Setting the duration of the path transition
      pathTransition.setDuration(Duration.millis(1000));

      //Setting the node for the transition
      pathTransition.setNode(circle);

      //Setting the path
      pathTransition.setPath(path);

      //Setting the orientation of the path
      pathTransition.setOrientation(PathTransition.OrientationType.
      ORTHOGONAL_TO_TAN GENT);

      //Setting the cycle count for the transition
      pathTransition.setCycleCount(50);

      //Setting auto reverse value to false
      pathTransition.setAutoReverse(false);

      //Playing the animation
      pathTransition.play();

      //Creating a Group object
      Group root = new Group(circle);

      //Creating a scene object
      Scene scene = new Scene(root, 600, 300);

      //Setting title to the Stage
      stage.setTitle("Path transition example");

      //Adding scene to the stage
      stage.setScene(scene);

      //Displaying the contents of the stage
      stage.show();
   }
   public static void main(String args[]){
      launch(args);
   }
}

使用以下命令，从命令提示符编译并执行已保存的 java 文件。

javac --module-path %PATH_TO_FX% --add-modules javafx.controls PathTransitionExample.java
java --module-path %PATH_TO_FX% --add-modules javafx.controls PathTransitionExample

执行后，上述程序会生成如下所示的 JavaFX 窗口。

path transition

Example 2

以下是一个沿着复杂路径转换圆的示例。将此代码保存在一个名为 PathTransitionExample2.java 的文件中。

import javafx.animation.PathTransition;
import javafx.application.Application;

import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;

import javafx.scene.shape.Circle;
import javafx.scene.shape.LineTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;

import javafx.stage.Stage;
import javafx.util.Duration;

public class PathTransitionExample2 extends Application {
   @Override
   public void start(Stage stage) {
      //Drawing a Circle
      Circle circle = new Circle();

      //Setting the position of the circle
      circle.setCenterX(300.0f);
      circle.setCenterY(135.0f);

      //Setting the radius of the circle
      circle.setRadius(25.0f);

      //Setting the color of the circle
      circle.setFill(Color.BROWN);

      //Setting the stroke width of the circle
      circle.setStrokeWidth(20);

      //Creating a Path
      Path path = new Path();

      //Moving to the starting point
      MoveTo moveTo = new MoveTo(108, 71);

      //Creating 1st line
      LineTo line1 = new LineTo(321, 161);

      //Creating 2nd line
      LineTo line2 = new LineTo(126,232);

      //Creating 3rd line
      LineTo line3 = new LineTo(232,52);

      //Creating 4th line
      LineTo line4 = new LineTo(269, 250);

      //Creating 5th line
      LineTo line5 = new LineTo(108, 71);

      //Adding all the elements to the path
      path.getElements().add(moveTo);
      path.getElements().addAll(line1, line2, line3, line4, line5);

      //Creating the path transition
      PathTransition pathTransition = new PathTransition();

      //Setting the duration of the transition
      pathTransition.setDuration(Duration.millis(1000));

      //Setting the node for the transition
      pathTransition.setNode(circle);

      //Setting the path for the transition
      pathTransition.setPath(path);

      //Setting the orientation of the path
      pathTransition.setOrientation(
         PathTransition.OrientationType.ORTHOGONAL_TO_TAN GENT);

      //Setting the cycle count for the transition
      pathTransition.setCycleCount(50);

      //Setting auto reverse value to true
      pathTransition.setAutoReverse(false);

      //Playing the animation
      pathTransition.play();

      //Creating a Group object
      Group root = new Group(circle);

      //Creating a scene object
      Scene scene = new Scene(root, 600, 300);

      //Setting title to the Stage
      stage.setTitle("Path transition example");

      //Adding scene to the stage
      stage.setScene(scene);

      //Displaying the contents of the stage
      stage.show();
   }
   public static void main(String args[]){
      launch(args);
   }
}

使用以下命令，从命令提示符编译并执行已保存的 java 文件。

javac --module-path %PATH_TO_FX% --add-modules javafx.controls PathTransitionExample2.java
java --module-path %PATH_TO_FX% --add-modules javafx.controls PathTransitionExample2

执行后，上述程序会生成如下所示的 JavaFX 窗口。

path transition example