如何使图像循环到屏幕的另一侧

Question

我为我正在进行的一个项目制作了一个this测试程序。它绘制了一辆汽车，并从左到右在JFrame上移动。我想做的是，一旦汽车物体完全通过框架的另一侧，它就会在另一侧循环回来。我想我必须在名为animationTester的主类中为计时器使用一个外部循环，但我不完全确定我想在循环中放入什么。还有人告诉我，我不能把窗口的大小硬编码到程序中。不管怎样，这是我的课。

ShapeIcon类

import java.awt.*;
import java.util.*;
import javax.swing.*;
/**
An icon that contains a moveable shape.
*/
public class ShapeIcon implements Icon
{
private int width;
private int height;
private MoveableShape shape;
public ShapeIcon(MoveableShape shape,
int width, int height)
{
this.shape = shape;
this.width = width;
this.height = height;
}
public int getIconWidth()
{
return width;
}
public int getIconHeight()
{
return height;
}
public void paintIcon(Component c, Graphics g, int x, int y)
{
Graphics2D g2 = (Graphics2D) g;
shape.draw(g2); // has draw method since it implements MoveableShape
}

}

CarShape类

import java.awt.*;
import java.awt.geom.*;
import java.util.*;
/**
A car that can be moved around.
*/
public class CarShape implements MoveableShape
{
private int x;
private int y;
private int width;
/**
Constructs a car item.
@param x the left of the bounding rectangle
@param y the top of the bounding rectangle
@param width the width of the bounding rectangle
*/
public CarShape(int x, int y, int width)
{
this.x = x;
this.y = y;
this.width = width;
}
public void translate(int dx, int dy)
{
x += dx;
y += dy;
}
public void draw(Graphics2D g2)
{
Rectangle2D.Double body
= new Rectangle2D.Double(x, y + width / 6, 
width - 1, width / 6);
Ellipse2D.Double frontTire
= new Ellipse2D.Double(x + width / 6, y + width / 3, 
width / 6, width / 6);
Ellipse2D.Double rearTire
= new Ellipse2D.Double(x + width * 2 / 3, y + width / 3,
width / 6, width / 6);
// The bottom of the front windshield
Point2D.Double r1
= new Point2D.Double(x + width / 6, y + width / 6);
// The front of the roof
Point2D.Double r2
= new Point2D.Double(x + width / 3, y);
// The rear of the roof
Point2D.Double r3
= new Point2D.Double(x + width * 2 / 3, y);
// The bottom of the rear windshield
Point2D.Double r4
= new Point2D.Double(x + width * 5 / 6, y + width / 6);
Line2D.Double frontWindshield
= new Line2D.Double(r1, r2);
Line2D.Double roofTop
= new Line2D.Double(r2, r3);
Line2D.Double rearWindshield
= new Line2D.Double(r3, r4);
g2.draw(body);
g2.draw(frontTire);
g2.draw(rearTire);
g2.draw(frontWindshield);
g2.draw(roofTop);
g2.draw(rearWindshield);
}

}

MoveableShape类

import java.awt.*;
/**
A shape that can be moved around.
*/
public interface MoveableShape
{
/**
Draws the shape.
@param g2 the graphics context
*/
void draw(Graphics2D g2);
/**
Moves the shape by a given amount.
@param dx the amount to translate in x-direction
@param dy the amount to translate in y-direction
*/
void translate(int dx, int dy);
}

主类

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
This program implements an animation that moves
a car shape.
*/
public class AnimationTester
{
private static final int ICON_WIDTH = 400;
private static final int ICON_HEIGHT = 100;
private static final int CAR_WIDTH = 100;
public static void main(String[] args)
{
JFrame frame = new JFrame();
final MoveableShape shape
= new CarShape(0, 0, CAR_WIDTH);
ShapeIcon icon = new ShapeIcon(shape,
ICON_WIDTH, ICON_HEIGHT);
final JLabel label = new JLabel(icon);
frame.setLayout(new FlowLayout());
frame.add(label);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
final int DELAY = 100;
// Milliseconds between timer ticks
Timer t = new Timer(DELAY, new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
shape.translate(1, 0);
label.repaint();
}
});
t.start();
}

}

Answer 1

您可以修改translate方法以允许end参数，这样当汽车到达帧的末尾时，它会再次启动：

public void translate(int dx, int dy, int end) {
x += dx;
y += dy;
if (end == x) {
x = -100;
}
}

然后将帧.getWidth((传递到AnimationTester.class:上的translate调用

Timer t = new Timer(DELAY, new ActionListener() {
public void actionPerformed(ActionEvent event) {
car.translate(1, 0, frame.getWidth());
label.repaint();
}
});

我希望它能有所帮助：(