Javafx 简明教程

JavaFX - Intersection Operation

与并集操作类似，交集操作从根本上用于集合论中。顾名思义，该操作被定义为将两个不同的集合交叉到一个集合中。因此，从两个或多个集合中检索共有的元素；忽略重复的元素。然后，这一概念被计算机编程中的各种技术所采用。

Similar to the Union operation, the intersection operation was fundamentally used in set theory. As the name suggests, this operation is defined as the intersection of two different sets into one. Hence, the common elements from two or more sets are retrieved; ignoring duplicate elements. This concept is then adopted by various techniques in computer programming.

例如，它也用于 C、C++、Java、Python 等等的编程语言中，作为一个运算符或方法。同样，JavaFX 也在 2D 形状上提供了交集操作。

For instance, it is also used in programming languages like C, C++, Java, Python etc. as an operator or a method. Similarly, JavaFX also provides intersection operation on 2D shapes.

Intersection Operation in JavaFX

JavaFX 允许您对 2D 形状执行交集操作，其中，两个或多个形状的区域交叉在一起，并且这些形状的公共区域作为结果被获取。因此，此操作将两个或多个形状作为输入，并将它们之间的交集区域作为结果返回，如下所示。

JavaFX allows you to perform intersection operation on 2D shapes, where, the areas of two or more shapes are intersected together and the common area of these shapes is obtained as a result. Thus, this operation takes two or more shapes as inputs and returns the intersection area between them as shown below.

intersection operation

您可以使用名为 intersect() 的方法对形状执行交集操作。既然这是一个静态方法，您应该使用类名（Shape 或其子类）调用它，如下所示。

You can perform an intersection operation on the shapes using the method named intersect(). Since this is a static method, you should call it using the class name (Shape or its subclasses) as shown below.

Shape shape = Shape.intersect(circle1, circle2);

以下是一个交集操作的示例。在其中，我们绘制两个圆，并对它们执行交集操作。将此代码保存在名为 IntersectionExample.java 的文件中

Following is an example of the intersection operation. In here, we are drawing two circles and performing a intersection operation on them. Save this code in a file with the name IntersectionExample.java

Example

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Shape;

public class IntersectionExample extends Application {
   @Override
   public void start(Stage stage) {
      //Drawing Circle1
      Circle circle1 = new Circle();

      //Setting the position of the circle
      circle1.setCenterX(250.0f);
      circle1.setCenterY(135.0f);

      //Setting the radius of the circle
      circle1.setRadius(100.0f);

      //Setting the color of the circle
      circle1.setFill(Color.DARKSLATEBLUE);

      //Drawing Circle2
      Circle circle2 = new Circle();

      //Setting the position of the circle
      circle2.setCenterX(350.0f);
      circle2.setCenterY(135.0f);

      //Setting the radius of the circle
      circle2.setRadius(100.0f);

      //Setting the color of the circle
      circle2.setFill(Color.BLUE);

      //Performing intersection operation on the circle
      Shape shape = Shape.intersect(circle1, circle2);

      //Setting the fill color to the result
      shape.setFill(Color.DARKSLATEBLUE);

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

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

      //Setting title to the Stage
      stage.setTitle("Intersection 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。

Compile and execute the saved java file from the command prompt using the following commands.

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

执行上述程序时，生成一个 JavaFX 窗口，显示以下输出 −

On executing, the above program generates a JavaFX window displaying the following output −

intersection operation output

Example

现在，尝试对两个椭圆形状执行交集操作（以检索它们之间的公共区域）。将该文件另存为 EllipseIntersectionOperation.java 。

Now, let us try to perform intersection operation on two elliptical shapes (to retrieve the common area between them). Save this file under the name EllipseIntersectionOperation.java.

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.scene.shape.Ellipse;
import javafx.scene.shape.Shape;

public class EllipseIntersectionOperation extends Application {
   @Override
   public void start(Stage stage) {
      Ellipse ellipse1 = new Ellipse();
      ellipse1.setCenterX(250.0f);
      ellipse1.setCenterY(100.0f);
      ellipse1.setRadiusX(150.0f);
      ellipse1.setRadiusY(75.0f);
      ellipse1.setFill(Color.BLUE);

      Ellipse ellipse2 = new Ellipse();
      ellipse2.setCenterX(350.0f);
      ellipse2.setCenterY(100.0f);
      ellipse2.setRadiusX(150.0f);
      ellipse2.setRadiusY(75.0f);
      ellipse2.setFill(Color.RED);

      Shape shape = Shape.intersect(ellipse1, ellipse2);

      //Setting the fill color to the result
      shape.setFill(Color.DARKSLATEBLUE);

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

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

      //Setting title to the Stage
      stage.setTitle("Intersection 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。

Compile and execute the saved java file from the command prompt using the following commands.

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

执行上述程序时，生成一个 JavaFX 窗口，显示以下输出 −

On executing, the above program generates a JavaFX window displaying the following output −

ellipse intersect