panel2d.java

来自「java learn PPT java learn PPT java learn」· Java 代码 · 共 89 行

package magic.awtex;

import java.awt.*;
import java.awt.geom.*;
import java.util.*;

import magic.graphics.*;

// 定义一个可以容纳其他组件的面板
public class Panel2D
    extends Container2D
{
  // 背景图片
  protected Image background;

  // 用指定的背景图片和位置创建一个新的Panel2D对象
  protected Panel2D(Image bgImage, Vector2D p)
  {
    super(p);

    background = bgImage;
  }

  // 在面板上指定的位置添加组件
  // 注意所传入的x,y值是相对于面板原点的 (左上角)
  public void add(Component2D c, double x, double y)
  {
    c.setX(getX() + x);
    c.setY(getY() + y);

    // 确保组件在面板边界之内
    if (c.getX() + c.getBounds().getWidth() > getX() + getBounds().getWidth()) {
      c.setX(getX() + getBounds().getWidth() - c.getBounds().getWidth());
    }

    if (c.getY() + c.getBounds().getHeight() > getY() + getBounds().getHeight()) {
      c.setY(getY() + getBounds().getHeight() - c.getBounds().getHeight());
    }

    c.update();
    c.updateBounds();
    components.add(c);
  }

  // 绘制面板和它的组件
  public void paint(Graphics2D g2d)
  {
    // 绘制背景
    if (background != null) {
      g2d.drawImage(background, (int) getX(), (int) getY(),
                    AnimationStrip.observer);
    }

    // 绘制面板上的组件
    for (e = components.elements(); e.hasMoreElements(); ) {
      ( (Component2D) e.nextElement()).paint(g2d);
    }
  }

  // 根据指定的偏移值绘制面板和它的组件
  public void paint(Graphics2D g2d, double dx, double dy)
  {
    if (background != null) {
      g2d.drawImage(background, (int) (getX() + dx), (int) (getY() + dy),
                    AnimationStrip.observer);
    }

    for (e = components.elements(); e.hasMoreElements(); ) {
      ( (Component2D) e.nextElement()).paint(g2d, dx, dy);
    }
  }

  // 更新面板的边界--如果面板没有图片,则不会尝试去计算面板的边界
  // will be made to calculate the panel's bounds
  public void updateBounds()
  {
    if (background != null) {
      frameWidth = background.getWidth(AnimationStrip.observer);
      frameHeight = background.getHeight(AnimationStrip.observer);
    }
    else {
      frameWidth = Integer.MAX_VALUE;
      frameHeight = Integer.MAX_VALUE;
    }

    bounds.setRect(pos.getX(), pos.getY(), frameWidth, frameHeight);
  }

} // Panel2D