jpgencoder.as

用摄像头在线拍照片,上传到服务器,也可以自己画一个图片上传到服务器

				tmp6 = data[dataOff+ 8] - data[dataOff+48];
				tmp2 = data[dataOff+16] + data[dataOff+40];
				tmp5 = data[dataOff+16] - data[dataOff+40];
				tmp3 = data[dataOff+24] + data[dataOff+32];
				tmp4 = data[dataOff+24] - data[dataOff+32];
	
				/* Even part */
				tmp10 = tmp0 + tmp3;	/* phase 2 */
				tmp13 = tmp0 - tmp3;
				tmp11 = tmp1 + tmp2;
				tmp12 = tmp1 - tmp2;
	
				data[dataOff+ 0] = tmp10 + tmp11; /* phase 3 */
				data[dataOff+32] = tmp10 - tmp11;
	
				z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */
				data[dataOff+16] = tmp13 + z1; /* phase 5 */
				data[dataOff+48] = tmp13 - z1;
	
				/* Odd part */
				tmp10 = tmp4 + tmp5; /* phase 2 */
				tmp11 = tmp5 + tmp6;
				tmp12 = tmp6 + tmp7;
	
				/* The rotator is modified from fig 4-8 to avoid extra negations. */
				z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */
				z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */
				z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */
				z3 = tmp11 * 0.707106781; /* c4 */
	
				z11 = tmp7 + z3;	/* phase 5 */
				z13 = tmp7 - z3;
	
				data[dataOff+40] = z13 + z2; /* phase 6 */
				data[dataOff+24] = z13 - z2;
				data[dataOff+ 8] = z11 + z4;
				data[dataOff+56] = z11 - z4;
	
				dataOff++; /* advance pointer to next column */
			}
	
			// Quantize/descale the coefficients
			for (i=0; i<64; i++) {
				// Apply the quantization and scaling factor & Round to nearest integer
				data[i] = Math.round((data[i]*fdtbl[i]));
			}
			return data;
		}
	
		// Chunk writing
	
		private function writeAPP0():void
		{
			writeWord(0xFFE0); // marker
			writeWord(16); // length
			writeByte(0x4A); // J
			writeByte(0x46); // F
			writeByte(0x49); // I
			writeByte(0x46); // F
			writeByte(0); // = "JFIF",'\0'
			writeByte(1); // versionhi
			writeByte(1); // versionlo
			writeByte(0); // xyunits
			writeWord(1); // xdensity
			writeWord(1); // ydensity
			writeByte(0); // thumbnwidth
			writeByte(0); // thumbnheight
		}
	
		private function writeSOF0(width:int, height:int):void
		{
			writeWord(0xFFC0); // marker
			writeWord(17);   // length, truecolor YUV JPG
			writeByte(8);    // precision
			writeWord(height);
			writeWord(width);
			writeByte(3);    // nrofcomponents
			writeByte(1);    // IdY
			writeByte(0x11); // HVY
			writeByte(0);    // QTY
			writeByte(2);    // IdU
			writeByte(0x11); // HVU
			writeByte(1);    // QTU
			writeByte(3);    // IdV
			writeByte(0x11); // HVV
			writeByte(1);    // QTV
		}
	
		private function writeDQT():void
		{
			writeWord(0xFFDB); // marker
			writeWord(132);	   // length
			writeByte(0);
			var i:int;
			for (i=0; i<64; i++) {
				writeByte(YTable[i]);
			}
			writeByte(1);
			for (i=0; i<64; i++) {
				writeByte(UVTable[i]);
			}
		}
	
		private function writeDHT():void
		{
			writeWord(0xFFC4); // marker
			writeWord(0x01A2); // length
			var i:int;
	
			writeByte(0); // HTYDCinfo
			for (i=0; i<16; i++) {
				writeByte(std_dc_luminance_nrcodes[i+1]);
			}
			for (i=0; i<=11; i++) {
				writeByte(std_dc_luminance_values[i]);
			}
	
			writeByte(0x10); // HTYACinfo
			for (i=0; i<16; i++) {
				writeByte(std_ac_luminance_nrcodes[i+1]);
			}
			for (i=0; i<=161; i++) {
				writeByte(std_ac_luminance_values[i]);
			}
	
			writeByte(1); // HTUDCinfo
			for (i=0; i<16; i++) {
				writeByte(std_dc_chrominance_nrcodes[i+1]);
			}
			for (i=0; i<=11; i++) {
				writeByte(std_dc_chrominance_values[i]);
			}
	
			writeByte(0x11); // HTUACinfo
			for (i=0; i<16; i++) {
				writeByte(std_ac_chrominance_nrcodes[i+1]);
			}
			for (i=0; i<=161; i++) {
				writeByte(std_ac_chrominance_values[i]);
			}
		}
	
		private function writeSOS():void
		{
			writeWord(0xFFDA); // marker
			writeWord(12); // length
			writeByte(3); // nrofcomponents
			writeByte(1); // IdY
			writeByte(0); // HTY
			writeByte(2); // IdU
			writeByte(0x11); // HTU
			writeByte(3); // IdV
			writeByte(0x11); // HTV
			writeByte(0); // Ss
			writeByte(0x3f); // Se
			writeByte(0); // Bf
		}
	
		// Core processing
		private var DU:Array = new Array(64);
	
		private function processDU(CDU:Array, fdtbl:Array, DC:Number, HTDC:Array, HTAC:Array):Number
		{
			var EOB:BitString = HTAC[0x00];
			var M16zeroes:BitString = HTAC[0xF0];
			var i:int;
	
			var DU_DCT:Array = fDCTQuant(CDU, fdtbl);
			//ZigZag reorder
			for (i=0;i<64;i++) {
				DU[ZigZag[i]]=DU_DCT[i];
			}
			var Diff:int = DU[0] - DC; DC = DU[0];
			//Encode DC
			if (Diff==0) {
				writeBits(HTDC[0]); // Diff might be 0
			} else {
				writeBits(HTDC[category[32767+Diff]]);
				writeBits(bitcode[32767+Diff]);
			}
			//Encode ACs
			var end0pos:int = 63;
			for (; (end0pos>0)&&(DU[end0pos]==0); end0pos--) {
			};
			//end0pos = first element in reverse order !=0
			if ( end0pos == 0) {
				writeBits(EOB);
				return DC;
			}
			i = 1;
			while ( i <= end0pos ) {
				var startpos:int = i;
				for (; (DU[i]==0) && (i<=end0pos); i++) {
				}
				var nrzeroes:int = i-startpos;
				if ( nrzeroes >= 16 ) {
					for (var nrmarker:int=1; nrmarker <= nrzeroes/16; nrmarker++) {
						writeBits(M16zeroes);
					}
					nrzeroes = int(nrzeroes&0xF);
				}
				writeBits(HTAC[nrzeroes*16+category[32767+DU[i]]]);
				writeBits(bitcode[32767+DU[i]]);
				i++;
			}
			if ( end0pos != 63 ) {
				writeBits(EOB);
			}
			return DC;
		}
	
		private var YDU:Array = new Array(64);
		private var UDU:Array = new Array(64);
		private var VDU:Array = new Array(64);
	
		private function RGB2YUV(img:BitmapData, xpos:int, ypos:int):void
		{
			var pos:int=0;
			for (var y:int=0; y<8; y++) {
				for (var x:int=0; x<8; x++) {
					var P:uint = img.getPixel32(xpos+x,ypos+y);
					var R:Number = Number((P>>16)&0xFF);
					var G:Number = Number((P>> 8)&0xFF);
					var B:Number = Number((P    )&0xFF);
					YDU[pos]=((( 0.29900)*R+( 0.58700)*G+( 0.11400)*B))-128;
					UDU[pos]=(((-0.16874)*R+(-0.33126)*G+( 0.50000)*B));
					VDU[pos]=((( 0.50000)*R+(-0.41869)*G+(-0.08131)*B));
					pos++;
				}
			}
		}
	
		public function JPGEncoder(quality:Number = 50)
		{
			if (quality <= 0) {
				quality = 1;
			}
			if (quality > 100) {
				quality = 100;
			}
			var sf:int = 0;
			if (quality < 50) {
				sf = int(5000 / quality);
			} else {
				sf = int(200 - quality*2);
			}
			// Create tables
			initHuffmanTbl();
			initCategoryNumber();
			initQuantTables(sf);
		}
	
		public function encode(image:BitmapData):ByteArray
		{
			// Initialize bit writer
			byteout = new ByteArray();
			bytenew=0;
			bytepos=7;
	
			// Add JPEG headers
			writeWord(0xFFD8); // SOI
			writeAPP0();
			writeDQT();
			writeSOF0(image.width,image.height);
			writeDHT();
			writeSOS();
 
	
			// Encode 8x8 macroblocks
			var DCY:Number=0;
			var DCU:Number=0;
			var DCV:Number=0;
			bytenew=0;
			bytepos=7;
			for (var ypos:int=0; ypos<image.height; ypos+=8) {
				for (var xpos:int=0; xpos<image.width; xpos+=8) {
					RGB2YUV(image, xpos, ypos);
					DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
					DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
					DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
				}
			}
	
			// Do the bit alignment of the EOI marker
			if ( bytepos >= 0 ) {
				var fillbits:BitString = new BitString();
				fillbits.len = bytepos+1;
				fillbits.val = (1<<(bytepos+1))-1;
				writeBits(fillbits);
			}
	
			writeWord(0xFFD9); //EOI
			return byteout;
		}
	}

}