编写一个JavaFX程序,使用橡皮条技术画圆。圆的大小以鼠标拖拽的方式确定。使用鼠标点击确定一个固定的位置作为圆心,计算当前鼠标位置与圆心的距离以确定圆的半径大小。
时间: 2024-03-24 17:38:18 浏览: 7
好的,我可以为你提供一份实现橡皮条技术画圆的JavaFX程序。下面是实现的步骤:
1. 创建一个JavaFX应用程序,并设置一个Canvas作为画布。
```java
public class RubberBandCircle extends Application {
private Canvas canvas;
private GraphicsContext gc;
private double centerX, centerY, radius;
@Override
public void start(Stage primaryStage) {
canvas = new Canvas(800, 600);
gc = canvas.getGraphicsContext2D();
canvas.setOnMousePressed(this::mousePressed);
canvas.setOnMouseDragged(this::mouseDragged);
canvas.setOnMouseReleased(this::mouseReleased);
VBox root = new VBox(canvas);
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.setTitle("Rubber Band Circle");
primaryStage.show();
}
private void mousePressed(MouseEvent event) {
centerX = event.getX();
centerY = event.getY();
radius = 0;
}
private void mouseDragged(MouseEvent event) {
gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight());
radius = Math.sqrt(Math.pow(event.getX() - centerX, 2) + Math.pow(event.getY() - centerY, 2));
gc.strokeOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
}
private void mouseReleased(MouseEvent event) {
gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight());
gc.strokeOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
}
public static void main(String[] args) {
launch(args);
}
}
```
2. 在鼠标按下时记录圆心的坐标,初始化圆的半径为0。
```java
private void mousePressed(MouseEvent event) {
centerX = event.getX();
centerY = event.getY();
radius = 0;
}
```
3. 在鼠标拖拽时计算圆的半径大小,并使用橡皮条技术画圆。
```java
private void mouseDragged(MouseEvent event) {
gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight());
radius = Math.sqrt(Math.pow(event.getX() - centerX, 2) + Math.pow(event.getY() - centerY, 2));
gc.strokeOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
}
```
4. 在鼠标释放时绘制最终的圆。
```java
private void mouseReleased(MouseEvent event) {
gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight());
gc.strokeOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
}
```
这样,就可以使用橡皮条技术画圆了。当鼠标拖拽时,程序会动态地计算圆的半径大小,并使用橡皮条技术画出圆形轮廓。当鼠标释放时,程序会绘制最终的圆。