| /** |
| * @license |
| 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. |
| */ |
| /** |
| * @license |
| JPEG encoder ported to JavaScript and optimized by Andreas Ritter, www.bytestrom.eu, 11/2009 |
| |
| Basic GUI blocking jpeg encoder |
| |
| v 0.9 |
| */ |
| |
| /** |
| * @fileoverview This code was ported from |
| * http://www.bytestrom.eu/blog/2009/1120a_jpeg_encoder_for_javascript and |
| * modified slightly for Closure. |
| */ |
| |
| goog.provide('goog.crypt.JpegEncoder'); |
| |
| goog.require('goog.crypt.base64'); |
| |
| /** |
| * Initializes the JpegEncoder. |
| * |
| * @constructor |
| * @param {number=} opt_quality The compression quality. Default 50. |
| */ |
| goog.crypt.JpegEncoder = function(opt_quality) { |
| var self = this; |
| var fround = Math.round; |
| var ffloor = Math.floor; |
| var YTable = new Array(64); |
| var UVTable = new Array(64); |
| var fdtbl_Y = new Array(64); |
| var fdtbl_UV = new Array(64); |
| var YDC_HT; |
| var UVDC_HT; |
| var YAC_HT; |
| var UVAC_HT; |
| |
| var bitcode = new Array(65535); |
| var category = new Array(65535); |
| var outputfDCTQuant = new Array(64); |
| var DU = new Array(64); |
| var byteout = []; |
| var bytenew = 0; |
| var bytepos = 7; |
| |
| var YDU = new Array(64); |
| var UDU = new Array(64); |
| var VDU = new Array(64); |
| var clt = new Array(256); |
| var RGB_YUV_TABLE = new Array(2048); |
| var currentQuality; |
| |
| var ZigZag = [ |
| 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 |
| ]; |
| |
| var std_dc_luminance_nrcodes = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0]; |
| var std_dc_luminance_values = [0,1,2,3,4,5,6,7,8,9,10,11]; |
| var std_ac_luminance_nrcodes = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d]; |
| var std_ac_luminance_values = [ |
| 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 |
| ]; |
| |
| var std_dc_chrominance_nrcodes = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0]; |
| var std_dc_chrominance_values = [0,1,2,3,4,5,6,7,8,9,10,11]; |
| var std_ac_chrominance_nrcodes = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77]; |
| var std_ac_chrominance_values = [ |
| 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 |
| ]; |
| |
| function initQuantTables(sf){ |
| var YQT = [ |
| 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 (var i = 0; i < 64; i++) { |
| var t = ffloor((YQT[i]*sf+50)/100); |
| if (t < 1) { |
| t = 1; |
| } else if (t > 255) { |
| t = 255; |
| } |
| YTable[ZigZag[i]] = t; |
| } |
| var UVQT = [ |
| 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 (var j = 0; j < 64; j++) { |
| var u = ffloor((UVQT[j]*sf+50)/100); |
| if (u < 1) { |
| u = 1; |
| } else if (u > 255) { |
| u = 255; |
| } |
| UVTable[ZigZag[j]] = u; |
| } |
| var aasf = [ |
| 1.0, 1.387039845, 1.306562965, 1.175875602, |
| 1.0, 0.785694958, 0.541196100, 0.275899379 |
| ]; |
| var k = 0; |
| for (var row = 0; row < 8; row++) |
| { |
| for (var col = 0; col < 8; col++) |
| { |
| fdtbl_Y[k] = (1.0 / (YTable [ZigZag[k]] * aasf[row] * aasf[col] * 8.0)); |
| fdtbl_UV[k] = (1.0 / (UVTable[ZigZag[k]] * aasf[row] * aasf[col] * 8.0)); |
| k++; |
| } |
| } |
| } |
| |
| function computeHuffmanTbl(nrcodes, std_table){ |
| var codevalue = 0; |
| var pos_in_table = 0; |
| var HT = new Array(); |
| for (var k = 1; k <= 16; k++) { |
| for (var j = 1; j <= nrcodes[k]; j++) { |
| HT[std_table[pos_in_table]] = []; |
| HT[std_table[pos_in_table]][0] = codevalue; |
| HT[std_table[pos_in_table]][1] = k; |
| pos_in_table++; |
| codevalue++; |
| } |
| codevalue*=2; |
| } |
| return HT; |
| } |
| |
| function initHuffmanTbl() |
| { |
| 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); |
| } |
| |
| function initCategoryNumber() |
| { |
| var nrlower = 1; |
| var nrupper = 2; |
| for (var cat = 1; cat <= 15; cat++) { |
| //Positive numbers |
| for (var nr = nrlower; nr<nrupper; nr++) { |
| category[32767+nr] = cat; |
| bitcode[32767+nr] = []; |
| bitcode[32767+nr][1] = cat; |
| bitcode[32767+nr][0] = nr; |
| } |
| //Negative numbers |
| for (var nrneg =-(nrupper-1); nrneg<=-nrlower; nrneg++) { |
| category[32767+nrneg] = cat; |
| bitcode[32767+nrneg] = []; |
| bitcode[32767+nrneg][1] = cat; |
| bitcode[32767+nrneg][0] = nrupper-1+nrneg; |
| } |
| nrlower <<= 1; |
| nrupper <<= 1; |
| } |
| } |
| |
| function initRGBYUVTable() { |
| for(var i = 0; i < 256;i++) { |
| RGB_YUV_TABLE[i] = 19595 * i; |
| RGB_YUV_TABLE[(i+ 256)>>0] = 38470 * i; |
| RGB_YUV_TABLE[(i+ 512)>>0] = 7471 * i + 0x8000; |
| RGB_YUV_TABLE[(i+ 768)>>0] = -11059 * i; |
| RGB_YUV_TABLE[(i+1024)>>0] = -21709 * i; |
| RGB_YUV_TABLE[(i+1280)>>0] = 32768 * i + 0x807FFF; |
| RGB_YUV_TABLE[(i+1536)>>0] = -27439 * i; |
| RGB_YUV_TABLE[(i+1792)>>0] = - 5329 * i; |
| } |
| } |
| |
| // IO functions |
| function writeBits(bs) |
| { |
| var value = bs[0]; |
| var posval = bs[1]-1; |
| while ( posval >= 0 ) { |
| if (value & (1 << posval) ) { |
| bytenew |= (1 << bytepos); |
| } |
| posval--; |
| bytepos--; |
| if (bytepos < 0) { |
| if (bytenew == 0xFF) { |
| writeByte(0xFF); |
| writeByte(0); |
| } |
| else { |
| writeByte(bytenew); |
| } |
| bytepos=7; |
| bytenew=0; |
| } |
| } |
| } |
| |
| function writeByte(value) |
| { |
| byteout.push(clt[value]); // write char directly instead of converting later |
| } |
| |
| function writeWord(value) |
| { |
| writeByte((value>>8)&0xFF); |
| writeByte((value )&0xFF); |
| } |
| |
| // DCT & quantization core |
| function fDCTQuant(data, fdtbl) |
| { |
| var d0, d1, d2, d3, d4, d5, d6, d7; |
| /* Pass 1: process rows. */ |
| var dataOff=0; |
| var i; |
| var I8 = 8; |
| var I64 = 64; |
| for (i=0; i<I8; ++i) |
| { |
| d0 = data[dataOff]; |
| d1 = data[dataOff+1]; |
| d2 = data[dataOff+2]; |
| d3 = data[dataOff+3]; |
| d4 = data[dataOff+4]; |
| d5 = data[dataOff+5]; |
| d6 = data[dataOff+6]; |
| d7 = data[dataOff+7]; |
| |
| var tmp0 = d0 + d7; |
| var tmp7 = d0 - d7; |
| var tmp1 = d1 + d6; |
| var tmp6 = d1 - d6; |
| var tmp2 = d2 + d5; |
| var tmp5 = d2 - d5; |
| var tmp3 = d3 + d4; |
| var tmp4 = d3 - d4; |
| |
| /* Even part */ |
| var tmp10 = tmp0 + tmp3; /* phase 2 */ |
| var tmp13 = tmp0 - tmp3; |
| var tmp11 = tmp1 + tmp2; |
| var tmp12 = tmp1 - tmp2; |
| |
| data[dataOff] = tmp10 + tmp11; /* phase 3 */ |
| data[dataOff+4] = tmp10 - tmp11; |
| |
| var 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. */ |
| var z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */ |
| var z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */ |
| var z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */ |
| var z3 = tmp11 * 0.707106781; /* c4 */ |
| |
| var z11 = tmp7 + z3; /* phase 5 */ |
| var 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<I8; ++i) |
| { |
| d0 = data[dataOff]; |
| d1 = data[dataOff + 8]; |
| d2 = data[dataOff + 16]; |
| d3 = data[dataOff + 24]; |
| d4 = data[dataOff + 32]; |
| d5 = data[dataOff + 40]; |
| d6 = data[dataOff + 48]; |
| d7 = data[dataOff + 56]; |
| |
| var tmp0p2 = d0 + d7; |
| var tmp7p2 = d0 - d7; |
| var tmp1p2 = d1 + d6; |
| var tmp6p2 = d1 - d6; |
| var tmp2p2 = d2 + d5; |
| var tmp5p2 = d2 - d5; |
| var tmp3p2 = d3 + d4; |
| var tmp4p2 = d3 - d4; |
| |
| /* Even part */ |
| var tmp10p2 = tmp0p2 + tmp3p2; /* phase 2 */ |
| var tmp13p2 = tmp0p2 - tmp3p2; |
| var tmp11p2 = tmp1p2 + tmp2p2; |
| var tmp12p2 = tmp1p2 - tmp2p2; |
| |
| data[dataOff] = tmp10p2 + tmp11p2; /* phase 3 */ |
| data[dataOff+32] = tmp10p2 - tmp11p2; |
| |
| var z1p2 = (tmp12p2 + tmp13p2) * 0.707106781; /* c4 */ |
| data[dataOff+16] = tmp13p2 + z1p2; /* phase 5 */ |
| data[dataOff+48] = tmp13p2 - z1p2; |
| |
| /* Odd part */ |
| tmp10p2 = tmp4p2 + tmp5p2; /* phase 2 */ |
| tmp11p2 = tmp5p2 + tmp6p2; |
| tmp12p2 = tmp6p2 + tmp7p2; |
| |
| /* The rotator is modified from fig 4-8 to avoid extra negations. */ |
| var z5p2 = (tmp10p2 - tmp12p2) * 0.382683433; /* c6 */ |
| var z2p2 = 0.541196100 * tmp10p2 + z5p2; /* c2-c6 */ |
| var z4p2 = 1.306562965 * tmp12p2 + z5p2; /* c2+c6 */ |
| var z3p2 = tmp11p2 * 0.707106781; /* c4 */ |
| |
| var z11p2 = tmp7p2 + z3p2; /* phase 5 */ |
| var z13p2 = tmp7p2 - z3p2; |
| |
| data[dataOff+40] = z13p2 + z2p2; /* phase 6 */ |
| data[dataOff+24] = z13p2 - z2p2; |
| data[dataOff+ 8] = z11p2 + z4p2; |
| data[dataOff+56] = z11p2 - z4p2; |
| |
| dataOff++; /* advance pointer to next column */ |
| } |
| |
| // Quantize/descale the coefficients |
| var fDCTQuant; |
| for (i=0; i<I64; ++i) |
| { |
| // Apply the quantization and scaling factor & Round to nearest integer |
| fDCTQuant = data[i]*fdtbl[i]; |
| outputfDCTQuant[i] = (fDCTQuant > 0.0) ? ((fDCTQuant + 0.5)|0) : ((fDCTQuant - 0.5)|0); |
| //outputfDCTQuant[i] = fround(fDCTQuant); |
| |
| } |
| return outputfDCTQuant; |
| } |
| |
| function writeAPP0() |
| { |
| 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 |
| } |
| |
| function writeSOF0(width, height) |
| { |
| 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 |
| } |
| |
| function writeDQT() |
| { |
| writeWord(0xFFDB); // marker |
| writeWord(132); // length |
| writeByte(0); |
| for (var i=0; i<64; i++) { |
| writeByte(YTable[i]); |
| } |
| writeByte(1); |
| for (var j=0; j<64; j++) { |
| writeByte(UVTable[j]); |
| } |
| } |
| |
| function writeDHT() |
| { |
| writeWord(0xFFC4); // marker |
| writeWord(0x01A2); // length |
| |
| writeByte(0); // HTYDCinfo |
| for (var i=0; i<16; i++) { |
| writeByte(std_dc_luminance_nrcodes[i+1]); |
| } |
| for (var j=0; j<=11; j++) { |
| writeByte(std_dc_luminance_values[j]); |
| } |
| |
| writeByte(0x10); // HTYACinfo |
| for (var k=0; k<16; k++) { |
| writeByte(std_ac_luminance_nrcodes[k+1]); |
| } |
| for (var l=0; l<=161; l++) { |
| writeByte(std_ac_luminance_values[l]); |
| } |
| |
| writeByte(1); // HTUDCinfo |
| for (var m=0; m<16; m++) { |
| writeByte(std_dc_chrominance_nrcodes[m+1]); |
| } |
| for (var n=0; n<=11; n++) { |
| writeByte(std_dc_chrominance_values[n]); |
| } |
| |
| writeByte(0x11); // HTUACinfo |
| for (var o=0; o<16; o++) { |
| writeByte(std_ac_chrominance_nrcodes[o+1]); |
| } |
| for (var p=0; p<=161; p++) { |
| writeByte(std_ac_chrominance_values[p]); |
| } |
| } |
| |
| function writeSOS() |
| { |
| 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 |
| } |
| |
| function processDU(CDU, fdtbl, DC, HTDC, HTAC){ |
| var EOB = HTAC[0x00]; |
| var M16zeroes = HTAC[0xF0]; |
| var pos; |
| var I16 = 16; |
| var I63 = 63; |
| var I64 = 64; |
| var DU_DCT = fDCTQuant(CDU, fdtbl); |
| //ZigZag reorder |
| for (var j=0;j<I64;++j) { |
| DU[ZigZag[j]]=DU_DCT[j]; |
| } |
| var Diff = DU[0] - DC; DC = DU[0]; |
| //Encode DC |
| if (Diff==0) { |
| writeBits(HTDC[0]); // Diff might be 0 |
| } else { |
| pos = 32767+Diff; |
| writeBits(HTDC[category[pos]]); |
| writeBits(bitcode[pos]); |
| } |
| //Encode ACs |
| var end0pos = 63; // was const... which is crazy |
| for (; (end0pos>0)&&(DU[end0pos]==0); end0pos--) {}; |
| //end0pos = first element in reverse order !=0 |
| if ( end0pos == 0) { |
| writeBits(EOB); |
| return DC; |
| } |
| var i = 1; |
| var lng; |
| while ( i <= end0pos ) { |
| var startpos = i; |
| for (; (DU[i]==0) && (i<=end0pos); ++i) {} |
| var nrzeroes = i-startpos; |
| if ( nrzeroes >= I16 ) { |
| lng = nrzeroes>>4; |
| for (var nrmarker=1; nrmarker <= lng; ++nrmarker) |
| writeBits(M16zeroes); |
| nrzeroes = nrzeroes&0xF; |
| } |
| pos = 32767+DU[i]; |
| writeBits(HTAC[(nrzeroes<<4)+category[pos]]); |
| writeBits(bitcode[pos]); |
| i++; |
| } |
| if ( end0pos != I63 ) { |
| writeBits(EOB); |
| } |
| return DC; |
| } |
| |
| function initCharLookupTable(){ |
| var sfcc = String.fromCharCode; |
| for(var i=0; i < 256; i++){ ///// ACHTUNG // 255 |
| clt[i] = sfcc(i); |
| } |
| } |
| |
| /** |
| * Encodes ImageData to JPEG. |
| * |
| * @param {ImageData} image |
| * @param {number=} opt_quality The compression quality. |
| * @return {string} base64-encoded JPEG data. |
| */ |
| this.encode = function(image,opt_quality) // image data object |
| { |
| if(opt_quality) setQuality(opt_quality); |
| |
| // Initialize bit writer |
| byteout = new Array(); |
| bytenew=0; |
| bytepos=7; |
| |
| // Add JPEG headers |
| writeWord(0xFFD8); // SOI |
| writeAPP0(); |
| writeDQT(); |
| writeSOF0(image.width,image.height); |
| writeDHT(); |
| writeSOS(); |
| |
| |
| // Encode 8x8 macroblocks |
| var _DCY=0; |
| var _DCU=0; |
| var _DCV=0; |
| |
| bytenew=0; |
| bytepos=7; |
| |
| |
| this.encode.displayName = "_encode_"; |
| |
| var imageData = image.data; |
| var width = image.width; |
| var height = image.height; |
| |
| var quadWidth = width*4; |
| var tripleWidth = width*3; |
| |
| var x, y = 0; |
| var r, g, b; |
| var start,p, col,row,pos; |
| while(y < height){ |
| x = 0; |
| while(x < quadWidth){ |
| start = quadWidth * y + x; |
| p = start; |
| col = -1; |
| row = 0; |
| |
| for(pos=0; pos < 64; pos++){ |
| row = pos >> 3;// /8 |
| col = ( pos & 7 ) * 4; // %8 |
| p = start + ( row * quadWidth ) + col; |
| |
| if(y+row >= height){ // padding bottom |
| p-= (quadWidth*(y+1+row-height)); |
| } |
| |
| if(x+col >= quadWidth){ // padding right |
| p-= ((x+col) - quadWidth +4) |
| } |
| |
| r = imageData[ p++ ]; |
| g = imageData[ p++ ]; |
| b = imageData[ p++ ]; |
| |
| |
| /* // calculate YUV values dynamically |
| YDU[pos]=((( 0.29900)*r+( 0.58700)*g+( 0.11400)*b))-128; //-0x80 |
| UDU[pos]=(((-0.16874)*r+(-0.33126)*g+( 0.50000)*b)); |
| VDU[pos]=((( 0.50000)*r+(-0.41869)*g+(-0.08131)*b)); |
| */ |
| |
| // use lookup table (slightly faster) |
| YDU[pos] = ((RGB_YUV_TABLE[r] + RGB_YUV_TABLE[(g + 256)>>0] + RGB_YUV_TABLE[(b + 512)>>0]) >> 16)-128; |
| UDU[pos] = ((RGB_YUV_TABLE[(r + 768)>>0] + RGB_YUV_TABLE[(g + 1024)>>0] + RGB_YUV_TABLE[(b + 1280)>>0]) >> 16)-128; |
| VDU[pos] = ((RGB_YUV_TABLE[(r + 1280)>>0] + RGB_YUV_TABLE[(g + 1536)>>0] + RGB_YUV_TABLE[(b + 1792)>>0]) >> 16)-128; |
| |
| } |
| |
| _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); |
| x+=32; |
| } |
| y+=8; |
| } |
| |
| |
| //////////////////////////////////////////////////////////////// |
| |
| // Do the bit alignment of the EOI marker |
| if ( bytepos >= 0 ) { |
| var fillbits = []; |
| fillbits[1] = bytepos+1; |
| fillbits[0] = (1<<(bytepos+1))-1; |
| writeBits(fillbits); |
| } |
| |
| writeWord(0xFFD9); //EOI |
| |
| var jpegDataUri = 'data:image/jpeg;base64,' |
| + goog.crypt.base64.encodeString(byteout.join('')); |
| |
| byteout = []; |
| |
| return jpegDataUri |
| } |
| |
| function setQuality(quality){ |
| if (quality <= 0) { |
| quality = 1; |
| } |
| if (quality > 100) { |
| quality = 100; |
| } |
| |
| if(currentQuality == quality) return // don't recalc if unchanged |
| |
| var sf = 0; |
| if (quality < 50) { |
| sf = Math.floor(5000 / quality); |
| } else { |
| sf = Math.floor(200 - quality*2); |
| } |
| |
| initQuantTables(sf); |
| currentQuality = quality; |
| } |
| |
| function init(){ |
| if(!opt_quality) opt_quality = 50; |
| // Create tables |
| initCharLookupTable() |
| initHuffmanTbl(); |
| initCategoryNumber(); |
| initRGBYUVTable(); |
| |
| setQuality(opt_quality); |
| } |
| |
| init(); |
| |
| }; |