Permalink
Switch branches/tags
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
649 lines (584 sloc) 18.7 KB
/*
Copyright (c) 2008, Adobe Systems Incorporated
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Adobe Systems Incorporated nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.adobe.images
{
import flash.geom.*;
import flash.display.*;
import flash.utils.*;
/**
* Class that converts BitmapData into a valid JPEG
*/
public class JPGEncoder
{
// Static table initialization
private var ZigZag:Array = [
0, 1, 5, 6,14,15,27,28,
2, 4, 7,13,16,26,29,42,
3, 8,12,17,25,30,41,43,
9,11,18,24,31,40,44,53,
10,19,23,32,39,45,52,54,
20,22,33,38,46,51,55,60,
21,34,37,47,50,56,59,61,
35,36,48,49,57,58,62,63
];
private var YTable:Array = new Array(64);
private var UVTable:Array = new Array(64);
private var fdtbl_Y:Array = new Array(64);
private var fdtbl_UV:Array = new Array(64);
private function initQuantTables(sf:int):void
{
var i:int;
var t:Number;
var YQT:Array = [
16, 11, 10, 16, 24, 40, 51, 61,
12, 12, 14, 19, 26, 58, 60, 55,
14, 13, 16, 24, 40, 57, 69, 56,
14, 17, 22, 29, 51, 87, 80, 62,
18, 22, 37, 56, 68,109,103, 77,
24, 35, 55, 64, 81,104,113, 92,
49, 64, 78, 87,103,121,120,101,
72, 92, 95, 98,112,100,103, 99
];
for (i = 0; i < 64; i++) {
t = Math.floor((YQT[i]*sf+50)/100);
if (t < 1) {
t = 1;
} else if (t > 255) {
t = 255;
}
YTable[ZigZag[i]] = t;
}
var UVQT:Array = [
17, 18, 24, 47, 99, 99, 99, 99,
18, 21, 26, 66, 99, 99, 99, 99,
24, 26, 56, 99, 99, 99, 99, 99,
47, 66, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
];
for (i = 0; i < 64; i++) {
t = Math.floor((UVQT[i]*sf+50)/100);
if (t < 1) {
t = 1;
} else if (t > 255) {
t = 255;
}
UVTable[ZigZag[i]] = t;
}
var aasf:Array = [
1.0, 1.387039845, 1.306562965, 1.175875602,
1.0, 0.785694958, 0.541196100, 0.275899379
];
i = 0;
for (var row:int = 0; row < 8; row++)
{
for (var col:int = 0; col < 8; col++)
{
fdtbl_Y[i] = (1.0 / (YTable [ZigZag[i]] * aasf[row] * aasf[col] * 8.0));
fdtbl_UV[i] = (1.0 / (UVTable[ZigZag[i]] * aasf[row] * aasf[col] * 8.0));
i++;
}
}
}
private var YDC_HT:Array;
private var UVDC_HT:Array;
private var YAC_HT:Array;
private var UVAC_HT:Array;
private function computeHuffmanTbl(nrcodes:Array, std_table:Array):Array
{
var codevalue:int = 0;
var pos_in_table:int = 0;
var HT:Array = new Array();
for (var k:int=1; k<=16; k++) {
for (var j:int=1; j<=nrcodes[k]; j++) {
HT[std_table[pos_in_table]] = new BitString();
HT[std_table[pos_in_table]].val = codevalue;
HT[std_table[pos_in_table]].len = k;
pos_in_table++;
codevalue++;
}
codevalue*=2;
}
return HT;
}
private var std_dc_luminance_nrcodes:Array = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0];
private var std_dc_luminance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11];
private var std_ac_luminance_nrcodes:Array = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d];
private var std_ac_luminance_values:Array = [
0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,
0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,
0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,
0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,
0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,
0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,
0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,
0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,
0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,
0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,
0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,
0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,
0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
0xf9,0xfa
];
private var std_dc_chrominance_nrcodes:Array = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0];
private var std_dc_chrominance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11];
private var std_ac_chrominance_nrcodes:Array = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77];
private var std_ac_chrominance_values:Array = [
0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,
0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,
0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,
0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,
0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,
0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,
0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,
0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,
0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,
0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,
0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,
0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,
0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,
0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
0xf9,0xfa
];
private function initHuffmanTbl():void
{
YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values);
UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values);
YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values);
UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values);
}
private var bitcode:Array = new Array(65535);
private var category:Array = new Array(65535);
private function initCategoryNumber():void
{
var nrlower:int = 1;
var nrupper:int = 2;
var nr:int;
for (var cat:int=1; cat<=15; cat++) {
//Positive numbers
for (nr=nrlower; nr<nrupper; nr++) {
category[32767+nr] = cat;
bitcode[32767+nr] = new BitString();
bitcode[32767+nr].len = cat;
bitcode[32767+nr].val = nr;
}
//Negative numbers
for (nr=-(nrupper-1); nr<=-nrlower; nr++) {
category[32767+nr] = cat;
bitcode[32767+nr] = new BitString();
bitcode[32767+nr].len = cat;
bitcode[32767+nr].val = nrupper-1+nr;
}
nrlower <<= 1;
nrupper <<= 1;
}
}
// IO functions
private var byteout:ByteArray;
private var bytenew:int = 0;
private var bytepos:int = 7;
private function writeBits(bs:BitString):void
{
var value:int = bs.val;
var posval:int = bs.len-1;
while ( posval >= 0 ) {
if (value & uint(1 << posval) ) {
bytenew |= uint(1 << bytepos);
}
posval--;
bytepos--;
if (bytepos < 0) {
if (bytenew == 0xFF) {
writeByte(0xFF);
writeByte(0);
}
else {
writeByte(bytenew);
}
bytepos=7;
bytenew=0;
}
}
}
private function writeByte(value:int):void
{
byteout.writeByte(value);
}
private function writeWord(value:int):void
{
writeByte((value>>8)&0xFF);
writeByte((value )&0xFF);
}
// DCT & quantization core
private function fDCTQuant(data:Array, fdtbl:Array):Array
{
var tmp0:Number, tmp1:Number, tmp2:Number, tmp3:Number, tmp4:Number, tmp5:Number, tmp6:Number, tmp7:Number;
var tmp10:Number, tmp11:Number, tmp12:Number, tmp13:Number;
var z1:Number, z2:Number, z3:Number, z4:Number, z5:Number, z11:Number, z13:Number;
var i:int;
/* Pass 1: process rows. */
var dataOff:int=0;
for (i=0; i<8; i++) {
tmp0 = data[dataOff+0] + data[dataOff+7];
tmp7 = data[dataOff+0] - data[dataOff+7];
tmp1 = data[dataOff+1] + data[dataOff+6];
tmp6 = data[dataOff+1] - data[dataOff+6];
tmp2 = data[dataOff+2] + data[dataOff+5];
tmp5 = data[dataOff+2] - data[dataOff+5];
tmp3 = data[dataOff+3] + data[dataOff+4];
tmp4 = data[dataOff+3] - data[dataOff+4];
/* 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+4] = tmp10 - tmp11;
z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */
data[dataOff+2] = tmp13 + z1; /* phase 5 */
data[dataOff+6] = 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+5] = z13 + z2; /* phase 6 */
data[dataOff+3] = z13 - z2;
data[dataOff+1] = z11 + z4;
data[dataOff+7] = z11 - z4;
dataOff += 8; /* advance pointer to next row */
}
/* Pass 2: process columns. */
dataOff = 0;
for (i=0; i<8; i++) {
tmp0 = data[dataOff+ 0] + data[dataOff+56];
tmp7 = data[dataOff+ 0] - data[dataOff+56];
tmp1 = data[dataOff+ 8] + data[dataOff+48];
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++;
}
}
}
/**
* Constructor for JPEGEncoder class
*
* @param quality The quality level between 1 and 100 that detrmines the
* level of compression used in the generated JPEG
* @langversion ActionScript 3.0
* @playerversion Flash 9.0
* @tiptext
*/
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);
}
/**
* Created a JPEG image from the specified BitmapData
*
* @param image The BitmapData that will be converted into the JPEG format.
* @return a ByteArray representing the JPEG encoded image data.
* @langversion ActionScript 3.0
* @playerversion Flash 9.0
* @tiptext
*/
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;
}
}
}