/*
 * Copyright (c) 1996 Lysator Academic Computer Society, All Rights Reserved.
 */

package SE.liu.lysator.gfx;

import java.awt.*;
import java.awt.image.*;

/**
 * A class that produces a component displaying an image
 *
 * @version	1.0 24 Jan 1995
 * @author	Marcus Comstedt
 */
public class Icon extends Canvas implements ImageObserver {

  /**
   * The topleft layout variable
   */
  public static final int TOPLEFT = 0;

  /**
   * The center layout variable
   */
  public static final int CENTER = 1;

  /**
   * The scale layout variable
   */
  public static final int SCALE = 2;

  /**
   * The tile layout variable
   */
  public static final int TILE = 4;

  /**
   * The image for this icon.
   */
  Image image;

  /**
   * The width of this icons image.
   */
  int width;

  /**
   * The height of this icons image.
   */
  int height;

  /**
   * The image layout of this icon.
   */
  int layout;

  /**
   * Constructs an Icon with no image.
   */
  public Icon() {
    this(null);
  }

  /**
   * Constructs an Icon with an image, using CENTER layout.
   * @param image the icon image
   */
  public Icon(Image image) {
    this.image = image;
    layout = CENTER;
    if(image == null) {
      width = 0;
      height = 0;
    } else {
      width = image.getWidth(this);
      height = image.getHeight(this);
    }
  }    

  /**
   * Sets the image layout policy for the icon.  (Default = CENTER)
   * @param layout the layout value
   */

  public void setLayout(int layout) {
    this.layout = layout;
  }

  /** 
   * Paints the icon.
   * @param g the specified Graphics window
   * @see #update
   */
  public void paint(Graphics g) {
    if(image != null && width>0 && height>0) {
      Dimension dim = size();
      if((layout&SCALE)!=0)
	g.drawImage(image, 0, 0, dim.width, dim.height, this);
      else {
	int x=0;
	int y=0;
	if((layout&CENTER)!=0) {
	  x = (dim.width-width)>>1;
	  y = (dim.height-height)>>1;
	}
	if((layout&TILE)!=0) {
	  if(x>0) x-=((x+width-1)/width)*width;
	  if(y>0) y-=((y+height-1)/height)*height;
	  int x0=x;
	  for(x0=x; y<dim.height; y+=height)
	    for(x=x0; x<dim.width; x+=width)
	      g.drawImage(image, x, y, this);
	} else
	  g.drawImage(image, x, y, this);
      }
    }
  }

  public boolean imageUpdate(Image img, int infoflags,
			     int x, int y, int width, int height) {
    boolean repaint = false, ret = true;
    if(img != image)
      return false;
    if((infoflags&ImageObserver.ERROR) != 0) {
      this.width = 0;
      this.height = 0;
      resize(0,0);
      image = null;
      return false;
    }
    if((infoflags&ImageObserver.WIDTH) != 0) {
      this.width = width;
      if(this.height > 0) {
	resize(this.width, this.height);
	repaint = true;
      }
    }   
    if((infoflags&ImageObserver.HEIGHT) != 0) {
      this.height = height;
      if(this.width > 0) {
	resize(this.width, this.height);
	repaint = true;
      }
    }
    if((infoflags&ImageObserver.ALLBITS) != 0) {
      repaint=true;
      ret=false;
    }
    if((infoflags&ImageObserver.SOMEBITS) != 0)
      repaint=true;

    if(repaint) repaint();
    return ret;
  }
}