directgif89frame.java

Gif89Encoder！ JAVA环境下应用！

//******************************************************************************
// DirectGif89Frame.java
//******************************************************************************
package net.jmge.gif;

import java.awt.Image;
import java.awt.image.PixelGrabber;
import java.io.IOException;

//==============================================================================
/** Instances of this Gif89Frame subclass are constructed from RGB image info,
 *  either in the form of an Image object or a pixel array.
 *  <p>
 *  There is an important restriction to note.  It is only permissible to add
 *  DirectGif89Frame objects to a Gif89Encoder constructed without an explicit
 *  color map.  The GIF color table will be automatically generated from pixel
 *  information.
 *
 * @version 0.90 beta (15-Jul-2000)
 * @author J. M. G. Elliott ([e-mail])
 * @see Gif89Encoder
 * @see Gif89Frame
 * @see IndexGif89Frame
 */
public class DirectGif89Frame extends Gif89Frame {

  private int[] argbPixels;

  //----------------------------------------------------------------------------
  /** Construct an DirectGif89Frame from a Java image.
   *
   * @param img
   *   A java.awt.Image object that supports pixel-grabbing.
   * @exception IOException
   *   If the image is unencodable due to failure of pixel-grabbing.
   */  
  public DirectGif89Frame(Image img) throws IOException 
  {    
    PixelGrabber pg = new PixelGrabber(img, 0, 0, -1, -1, true);

    String errmsg = null;
    try {   
      if (!pg.grabPixels())
        errmsg = "can't grab pixels from image";     
    } catch (InterruptedException e) {
      errmsg = "interrupted grabbing pixels from image";
    }

    if (errmsg != null)
      throw new IOException(errmsg + " (" + getClass().getName() + ")");
    
    theWidth = pg.getWidth(); 
    theHeight = pg.getHeight();
    argbPixels = (int[]) pg.getPixels();
    ciPixels = new byte[argbPixels.length];
  }

  //----------------------------------------------------------------------------
  /** Construct an DirectGif89Frame from ARGB pixel data.
   *
   * @param width
   *   Width of the bitmap.
   * @param height
   *   Height of the bitmap.
   * @param argb_pixels
   *   Array containing at least width*height pixels in the format returned by
   *   java.awt.Color.getRGB().
   */
  public DirectGif89Frame(int width, int height, int argb_pixels[])
  {
    theWidth = width;
    theHeight = height;
    argbPixels = new int[theWidth * theHeight];
    System.arraycopy(argb_pixels, 0, argbPixels, 0, argbPixels.length);
    ciPixels = new byte[argbPixels.length];
  }

  //----------------------------------------------------------------------------
  Object getPixelSource() { return argbPixels; }
}