src/org/xwt/ImageDecoder.java

   1 // Copyright 2003 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 import org.xwt.translators.*;
   7
   8 /** Interface implemented by classes capable of decoding an image file into an int[] */
   9 public abstract class ImageDecoder {
  10
  11     /** returns the width of the image */
  12     public abstract int getWidth();
  13
  14     /** returns the height of the image */
  15     public abstract int getHeight();
  16
  17     /** returns the data of the image, as an array of 32-bit AARRGGBB samples */
  18     public abstract int[] getData();
  19
  20     /** loads the image described by string str, possibly blocking for a network load */
  21     public static ImageDecoder getImageDecoder(String str, final JS.Callable callback) {
  22
  23         if (str.indexOf(':') == -1) {
  24             String s = str;
  25             byte[] b = Resources.getResource(Resources.resolve(s + ".png", null));
  26             if (b != null) return PNG.decode(new ByteArrayInputStream(b), str);
  27             b = Resources.getResource(Resources.resolve(s + ".jpeg", null));
  28             if (b != null) return Platform.decodeJPEG(new ByteArrayInputStream(b), str);
  29             return null;
  30
  31         } else {
  32             java.lang.Thread thread = java.lang.Thread.currentThread();
  33             if (!(thread instanceof ThreadMessage)) {
  34                 if (Log.on) Log.log(Box.class, "HTTP images can not be loaded from the foreground thread");
  35                 return null;
  36             }
  37             // FIXME: use primitives here
  38             ThreadMessage mythread = (ThreadMessage)thread;
  39             mythread.setPriority(java.lang.Thread.MIN_PRIORITY);
  40             mythread.done.release();
  41             try {
  42                 HTTP http = new HTTP(str);
  43                 final HTTP.HTTPInputStream in = http.GET();
  44                 final int contentLength = in.getContentLength();
  45                 InputStream is = new FilterInputStream(in) {
  46                         int bytesDownloaded = 0;
  47                         boolean clear = true;
  48                         public int read() throws IOException {
  49                             bytesDownloaded++;
  50                             return super.read();
  51                         }
  52                         public int read(byte[] b, int off, int len) throws IOException {
  53                             int ret = super.read(b, off, len);
  54                             if (ret != -1) bytesDownloaded += ret;
  55                             if (clear && callback != null) {
  56                                 clear = false;
  57                                 ThreadMessage.newthread(new JS.Callable() {
  58                                         public Object call(JS.Array args_) throws JS.Exn {
  59                                             try {
  60                                                 JS.Array args = new JS.Array();
  61                                                 args.addElement(new Double(bytesDownloaded));
  62                                                 args.addElement(new Double(contentLength));
  63                                                 callback.call(args);
  64                                             } finally {
  65                                                 clear = true;
  66                                             }
  67                                             return null;
  68                                         }
  69                                     });
  70                             }
  71                             return ret;
  72                         }
  73                     };
  74
  75                 if (str.endsWith(".gif")) return GIF.decode(is, str);
  76                 else if (str.endsWith(".jpeg") || str.endsWith(".jpg")) return Platform.decodeJPEG(is, str);
  77                 else return PNG.decode(is, str);
  78
  79             } catch (IOException e) {
  80                 if (Log.on) Log.log(Box.class, "error while trying to load an image from " + str);
  81                 if (Log.on) Log.log(Box.class, e);
  82                 return null;
  83
  84             } finally {
  85                 MessageQueue.add(mythread);
  86                 mythread.setPriority(java.lang.Thread.NORM_PRIORITY);
  87                 mythread.go.block();
  88             }
  89         }
  90     }
  91
  92     /** gets an Image using getImage(), adds it to the cache, and creates a Picture from it */
  93     public static Picture getPicture(String os) {
  94         Picture ret = null;
  95         ret = (Picture)pictureCache.get(os);
  96         if (ret != null) return ret;
  97         ImageDecoder id = ImageDecoder.getImageDecoder(os, null);
  98         if (id == null) return null;
  99         ret = Platform.createPicture(id);
 100         pictureCache.put(os, ret);
 101         imageToNameMap.put(ret, os);
 102         return ret;
 103     }
 104
 105     /** caches images, keyed on resource name or url */
 106     public static Hash pictureCache = new Hash();
 107
 108     /** stores image names, keyed on image object */
 109     static Hash imageToNameMap = new Hash();
 110
 111 }