JPEG chunk をブラウザが表示できる順番に並び替える処理を追加

diff --git a/bitmap.js b/bitmap.js
index a878299..f7e070d 100644 (file)
--- a/bitmap.js
+++ b/bitmap.js
@@ -5,8 +5,60 @@
     FlappBitmap.prototype = {
 
     };
+    FlappBitmap.jpegChunkOffsets = function(jpegData) {
+       var offsetTable = {};
+       var ibit = new FlappIBit();
+       while (ibit.HasNext(2)) {
+           var marker = ibit.ui16be();
+           var offset = ibit.getBytePos();
+           switch (marker) {
+            case 0xFFD8: // SOI
+            case 0xFFD9: // EOI
+               break;
+            case 0xFFDA: // SOS + [RST] + EOI
+               length = ibit.len() - offset;
+               offsetTable[marker] = [offset, length]
+               break;
+           default:
+               length = ibit.ui16be() + 2;
+               offsetTable[marker] = [offset, length]
+
+               break;
+           }
+       }
+    }
+
     FlappBitmap.toJpeg = function(swfJpeg, jpegTables) {
-       return swfJpeg;
+       var hasDQT = false;
+       var offsetTable = FlappBitmap.jpegChunkOffsets(swfJpeg);
+       if (0xFFDB in offsetTable) {
+           hasDQT = true;
+       }
+       if (hasDQT === false) {
+           var offsetTable2 = FlappBitmap.jpegChunkOffsets(jpegTables);
+       }
+       var jpegArray = [0xFF, 0xD8]; // SOI
+       // APP0, SOF0, DQT, DHT, SOS
+       var jpegOrder = [0xFFE0, 0xFFC0, 0xFFDB, 0xFFC4, 0xFFDA];
+       for (var i = 0, l = jpegOrder; i < l ; i++) {
+           var marker = jpegOrder[i];
+           var swfJpegOffset = (marker in offsetTable)?true:false;
+           if (swfJpegOffset) {
+               var entry = offsetTable[marker];
+           } else {
+               var entry = offsetTable2[marker];
+           }
+           var offset = entry[0];
+           var enfoffset = offset + entry[1];
+           for (j = offset; j < enfoffset ; j++) {
+               if (swfJpegOffset) {
+                   jpegArray.join(swfJpeg[j]);
+               } else {
+                   jpegArray.join(jpegTables[j]);
+               }
+           }
+       }
+       return FlappString.ArrayToString(jpegArray).join('');
     };
     FlappBitmap.toPng = function(lossless) {
        ;