src/org/xwt/ImageDecoder.java

   1 // Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
   2 package org.xwt;
   3 import java.io.*;
   4 import org.xwt.js.*;
   5 import org.xwt.util.*;
   6
   7 /** Interface implemented by classes capable of decoding an image file into an int[] */
   8 public abstract class ImageDecoder {
   9
  10     /** returns the width of the image */
  11     public abstract int getWidth();
  12
  13     /** returns the height of the image */
  14     public abstract int getHeight();
  15
  16     /** returns the data of the image, as an array of 32-bit AARRGGBB samples */
  17     public abstract int[] getData();
  18
  19     /** loads the image described by string str, possibly blocking for a network load */
  20     public static ImageDecoder getImageDecoder(String str, final JS.Callable callback) {
  21
  22         if (str.indexOf(':') == -1) {
  23             String s = str;
  24             byte[] b = Resources.getResource(Resources.resolve(s + ".png", null));
  25             if (b != null) return PNG.decode(new ByteArrayInputStream(b), str);
  26             b = Resources.getResource(Resources.resolve(s + ".jpeg", null));
  27             if (b != null) return Platform.decodeJPEG(new ByteArrayInputStream(b), str);
  28             return null;
  29
  30         } else {
  31             java.lang.Thread thread = java.lang.Thread.currentThread();
  32             if (!(thread instanceof ThreadMessage)) {
  33                 if (Log.on) Log.log(Box.class, "HTTP images can not be loaded from the foreground thread");
  34                 return null;
  35             }
  36             // FIXME: use primitives here
  37             ThreadMessage mythread = (ThreadMessage)thread;
  38             mythread.setPriority(java.lang.Thread.MIN_PRIORITY);
  39             mythread.done.release();
  40             try {
  41                 HTTP http = new HTTP(str);
  42                 final HTTP.HTTPInputStream in = http.GET();
  43                 final int contentLength = in.getContentLength();
  44                 InputStream is = new FilterInputStream(in) {
  45                         int bytesDownloaded = 0;
  46                         boolean clear = true;
  47                         public int read() throws IOException {
  48                             bytesDownloaded++;
  49                             return super.read();
  50                         }
  51                         public int read(byte[] b, int off, int len) throws IOException {
  52                             int ret = super.read(b, off, len);
  53                             if (ret != -1) bytesDownloaded += ret;
  54                             if (clear && callback != null) {
  55                                 clear = false;
  56                                 ThreadMessage.newthread(new JS.Callable() {
  57                                         public Object call(JS.Array args_) throws JS.Exn {
  58                                             try {
  59                                                 JS.Array args = new JS.Array();
  60                                                 args.addElement(new Double(bytesDownloaded));
  61                                                 args.addElement(new Double(contentLength));
  62                                                 callback.call(args);
  63                                             } finally {
  64                                                 clear = true;
  65                                             }
  66                                             return null;
  67                                         }
  68                                     });
  69                             }
  70                             return ret;
  71                         }
  72                     };
  73
  74                 if (str.endsWith(".gif")) return GIF.decode(is, str);
  75                 else if (str.endsWith(".jpeg") || str.endsWith(".jpg")) return Platform.decodeJPEG(is, str);
  76                 else return PNG.decode(is, str);
  77
  78             } catch (IOException e) {
  79                 if (Log.on) Log.log(Box.class, "error while trying to load an image from " + str);
  80                 if (Log.on) Log.log(Box.class, e);
  81                 return null;
  82
  83             } finally {
  84                 MessageQueue.add(mythread);
  85                 mythread.setPriority(java.lang.Thread.NORM_PRIORITY);
  86                 mythread.go.block();
  87             }
  88         }
  89     }
  90
  91     /** gets an Image using getImage(), adds it to the cache, and creates a Picture from it */
  92     public static Picture getPicture(String os) {
  93         Picture ret = null;
  94         ret = (Picture)pictureCache.get(os);
  95         if (ret != null) return ret;
  96         ImageDecoder id = ImageDecoder.getImageDecoder(os, null);
  97         if (id == null) return null;
  98         ret = Platform.createPicture(id);
  99         pictureCache.put(os, ret);
 100         imageToNameMap.put(ret, os);
 101         return ret;
 102     }
 103
 104     /** caches images, keyed on resource name or url */
 105     public static Hash pictureCache = new Hash();
 106
 107     /** stores image names, keyed on image object */
 108     static Hash imageToNameMap = new Hash();
 109
 110 }