JavaFX - 路径转换



JavaFX 中的路径转换用于在特定路径上移动 JavaFX 节点(或对象)。这类似于平移转换,因为它也使对象从一个位置移动到另一个位置。但是,平移转换没有提供对象移动的连续路径;而路径转换则提供了。

任何 JavaFX 节点,例如 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。

JavaFX 中的路径转换

JavaFX 提供了一个 **PathTransition** 类来在 JavaFX 节点上应用路径转换。此类属于 **javafx.animation** 包。此转换创建一个路径动画,该动画使对象沿着特定路径移动并跨越其持续时间。

路径转换除了平移对象以重新定位它之外,别无其他作用。这种沿着路径的平移是通过定期更新节点在 X 和 Y 方向上的坐标,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 类提供了以下属性可应用于节点:

    **duration** - 此转换的持续时间。

    **node** - 此 PathTransition 的目标节点。

    **orientation** - 指定节点沿路径的垂直方向。

    **path** - 节点应在其轮廓上进行动画处理的形状。

示例 1

以下是演示 JavaFX 中路径转换的程序。将此代码保存在名为 **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 

输出

执行后,上述程序生成一个 JavaFX 窗口,如下所示。

Path Transition

示例 2

以下是一个沿着复杂路径转换圆形的示例。将此代码保存在名为 **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 

输出

执行后,上述程序生成一个 JavaFX 窗口,如下所示。

Path Transition Example
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