767 lines
20 KiB
JavaScript
767 lines
20 KiB
JavaScript
/*
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Copyright (c) 2008, Adobe Systems Incorporated
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of Adobe Systems Incorporated nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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JPEG encoder ported to JavaScript and optimized by Andreas Ritter, www.bytestrom.eu, 11/2009
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Basic GUI blocking jpeg encoder
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*/
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var btoa = btoa || function(buf) {
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return new Buffer(buf).toString('base64');
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};
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function JPEGEncoder(quality) {
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var self = this;
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var fround = Math.round;
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var ffloor = Math.floor;
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var YTable = new Array(64);
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var UVTable = new Array(64);
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var fdtbl_Y = new Array(64);
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var fdtbl_UV = new Array(64);
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var YDC_HT;
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var UVDC_HT;
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var YAC_HT;
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var UVAC_HT;
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var bitcode = new Array(65535);
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var category = new Array(65535);
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var outputfDCTQuant = new Array(64);
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var DU = new Array(64);
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var byteout = [];
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var bytenew = 0;
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var bytepos = 7;
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var YDU = new Array(64);
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var UDU = new Array(64);
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var VDU = new Array(64);
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var clt = new Array(256);
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var RGB_YUV_TABLE = new Array(2048);
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var currentQuality;
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var ZigZag = [
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0, 1, 5, 6,14,15,27,28,
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2, 4, 7,13,16,26,29,42,
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3, 8,12,17,25,30,41,43,
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9,11,18,24,31,40,44,53,
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10,19,23,32,39,45,52,54,
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20,22,33,38,46,51,55,60,
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21,34,37,47,50,56,59,61,
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35,36,48,49,57,58,62,63
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];
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var std_dc_luminance_nrcodes = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0];
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var std_dc_luminance_values = [0,1,2,3,4,5,6,7,8,9,10,11];
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var std_ac_luminance_nrcodes = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d];
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var std_ac_luminance_values = [
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0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,
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0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,
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0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
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0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,
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0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,
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0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
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0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,
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0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
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0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
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0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,
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0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,
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0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
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0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,
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0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,
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0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
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0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,
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0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,
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0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
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0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,
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0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
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0xf9,0xfa
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];
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var std_dc_chrominance_nrcodes = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0];
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var std_dc_chrominance_values = [0,1,2,3,4,5,6,7,8,9,10,11];
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var std_ac_chrominance_nrcodes = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77];
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var std_ac_chrominance_values = [
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0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,
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0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,
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0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
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0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,
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0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,
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0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
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0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,
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0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,
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0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
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0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,
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0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,
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0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
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0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,
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0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,
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0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
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0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,
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0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,
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0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
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0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,
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0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
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0xf9,0xfa
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];
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function initQuantTables(sf){
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var YQT = [
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16, 11, 10, 16, 24, 40, 51, 61,
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12, 12, 14, 19, 26, 58, 60, 55,
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14, 13, 16, 24, 40, 57, 69, 56,
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14, 17, 22, 29, 51, 87, 80, 62,
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18, 22, 37, 56, 68,109,103, 77,
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24, 35, 55, 64, 81,104,113, 92,
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49, 64, 78, 87,103,121,120,101,
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72, 92, 95, 98,112,100,103, 99
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];
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for (var i = 0; i < 64; i++) {
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var t = ffloor((YQT[i]*sf+50)/100);
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if (t < 1) {
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t = 1;
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} else if (t > 255) {
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t = 255;
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}
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YTable[ZigZag[i]] = t;
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}
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var UVQT = [
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17, 18, 24, 47, 99, 99, 99, 99,
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18, 21, 26, 66, 99, 99, 99, 99,
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24, 26, 56, 99, 99, 99, 99, 99,
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47, 66, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99
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];
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for (var j = 0; j < 64; j++) {
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var u = ffloor((UVQT[j]*sf+50)/100);
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if (u < 1) {
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u = 1;
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} else if (u > 255) {
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u = 255;
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}
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UVTable[ZigZag[j]] = u;
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}
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var aasf = [
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1.0, 1.387039845, 1.306562965, 1.175875602,
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1.0, 0.785694958, 0.541196100, 0.275899379
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];
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var k = 0;
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for (var row = 0; row < 8; row++)
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{
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for (var col = 0; col < 8; col++)
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{
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fdtbl_Y[k] = (1.0 / (YTable [ZigZag[k]] * aasf[row] * aasf[col] * 8.0));
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fdtbl_UV[k] = (1.0 / (UVTable[ZigZag[k]] * aasf[row] * aasf[col] * 8.0));
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k++;
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}
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}
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}
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function computeHuffmanTbl(nrcodes, std_table){
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var codevalue = 0;
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var pos_in_table = 0;
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var HT = new Array();
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for (var k = 1; k <= 16; k++) {
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for (var j = 1; j <= nrcodes[k]; j++) {
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HT[std_table[pos_in_table]] = [];
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HT[std_table[pos_in_table]][0] = codevalue;
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HT[std_table[pos_in_table]][1] = k;
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pos_in_table++;
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codevalue++;
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}
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codevalue*=2;
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}
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return HT;
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}
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function initHuffmanTbl()
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{
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YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values);
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UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values);
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YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values);
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UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values);
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}
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function initCategoryNumber()
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{
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var nrlower = 1;
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var nrupper = 2;
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for (var cat = 1; cat <= 15; cat++) {
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//Positive numbers
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for (var nr = nrlower; nr<nrupper; nr++) {
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category[32767+nr] = cat;
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bitcode[32767+nr] = [];
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bitcode[32767+nr][1] = cat;
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bitcode[32767+nr][0] = nr;
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}
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//Negative numbers
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for (var nrneg =-(nrupper-1); nrneg<=-nrlower; nrneg++) {
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category[32767+nrneg] = cat;
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bitcode[32767+nrneg] = [];
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bitcode[32767+nrneg][1] = cat;
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bitcode[32767+nrneg][0] = nrupper-1+nrneg;
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}
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nrlower <<= 1;
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nrupper <<= 1;
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}
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}
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function initRGBYUVTable() {
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for(var i = 0; i < 256;i++) {
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RGB_YUV_TABLE[i] = 19595 * i;
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RGB_YUV_TABLE[(i+ 256)>>0] = 38470 * i;
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RGB_YUV_TABLE[(i+ 512)>>0] = 7471 * i + 0x8000;
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RGB_YUV_TABLE[(i+ 768)>>0] = -11059 * i;
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RGB_YUV_TABLE[(i+1024)>>0] = -21709 * i;
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RGB_YUV_TABLE[(i+1280)>>0] = 32768 * i + 0x807FFF;
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RGB_YUV_TABLE[(i+1536)>>0] = -27439 * i;
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RGB_YUV_TABLE[(i+1792)>>0] = - 5329 * i;
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}
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}
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// IO functions
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function writeBits(bs)
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{
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var value = bs[0];
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var posval = bs[1]-1;
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while ( posval >= 0 ) {
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if (value & (1 << posval) ) {
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bytenew |= (1 << bytepos);
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}
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posval--;
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bytepos--;
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if (bytepos < 0) {
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if (bytenew == 0xFF) {
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writeByte(0xFF);
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writeByte(0);
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}
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else {
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writeByte(bytenew);
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}
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bytepos=7;
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bytenew=0;
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}
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}
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}
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function writeByte(value)
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{
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//byteout.push(clt[value]); // write char directly instead of converting later
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byteout.push(value);
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}
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function writeWord(value)
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{
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writeByte((value>>8)&0xFF);
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writeByte((value )&0xFF);
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}
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// DCT & quantization core
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function fDCTQuant(data, fdtbl)
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{
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var d0, d1, d2, d3, d4, d5, d6, d7;
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/* Pass 1: process rows. */
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var dataOff=0;
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var i;
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const I8 = 8;
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const I64 = 64;
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for (i=0; i<I8; ++i)
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{
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d0 = data[dataOff];
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d1 = data[dataOff+1];
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d2 = data[dataOff+2];
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d3 = data[dataOff+3];
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d4 = data[dataOff+4];
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d5 = data[dataOff+5];
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d6 = data[dataOff+6];
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d7 = data[dataOff+7];
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var tmp0 = d0 + d7;
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var tmp7 = d0 - d7;
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var tmp1 = d1 + d6;
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var tmp6 = d1 - d6;
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var tmp2 = d2 + d5;
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var tmp5 = d2 - d5;
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var tmp3 = d3 + d4;
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var tmp4 = d3 - d4;
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/* Even part */
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var tmp10 = tmp0 + tmp3; /* phase 2 */
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var tmp13 = tmp0 - tmp3;
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var tmp11 = tmp1 + tmp2;
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var tmp12 = tmp1 - tmp2;
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data[dataOff] = tmp10 + tmp11; /* phase 3 */
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data[dataOff+4] = tmp10 - tmp11;
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var z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */
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data[dataOff+2] = tmp13 + z1; /* phase 5 */
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data[dataOff+6] = tmp13 - z1;
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/* Odd part */
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tmp10 = tmp4 + tmp5; /* phase 2 */
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tmp11 = tmp5 + tmp6;
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tmp12 = tmp6 + tmp7;
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/* The rotator is modified from fig 4-8 to avoid extra negations. */
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var z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */
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var z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */
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var z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */
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var z3 = tmp11 * 0.707106781; /* c4 */
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var z11 = tmp7 + z3; /* phase 5 */
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var z13 = tmp7 - z3;
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data[dataOff+5] = z13 + z2; /* phase 6 */
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data[dataOff+3] = z13 - z2;
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data[dataOff+1] = z11 + z4;
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data[dataOff+7] = z11 - z4;
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dataOff += 8; /* advance pointer to next row */
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}
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/* Pass 2: process columns. */
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dataOff = 0;
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for (i=0; i<I8; ++i)
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{
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d0 = data[dataOff];
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d1 = data[dataOff + 8];
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d2 = data[dataOff + 16];
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d3 = data[dataOff + 24];
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d4 = data[dataOff + 32];
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d5 = data[dataOff + 40];
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d6 = data[dataOff + 48];
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d7 = data[dataOff + 56];
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var tmp0p2 = d0 + d7;
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var tmp7p2 = d0 - d7;
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var tmp1p2 = d1 + d6;
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var tmp6p2 = d1 - d6;
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var tmp2p2 = d2 + d5;
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var tmp5p2 = d2 - d5;
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var tmp3p2 = d3 + d4;
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var tmp4p2 = d3 - d4;
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/* Even part */
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var tmp10p2 = tmp0p2 + tmp3p2; /* phase 2 */
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var tmp13p2 = tmp0p2 - tmp3p2;
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var tmp11p2 = tmp1p2 + tmp2p2;
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var tmp12p2 = tmp1p2 - tmp2p2;
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data[dataOff] = tmp10p2 + tmp11p2; /* phase 3 */
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data[dataOff+32] = tmp10p2 - tmp11p2;
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var z1p2 = (tmp12p2 + tmp13p2) * 0.707106781; /* c4 */
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data[dataOff+16] = tmp13p2 + z1p2; /* phase 5 */
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data[dataOff+48] = tmp13p2 - z1p2;
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/* Odd part */
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tmp10p2 = tmp4p2 + tmp5p2; /* phase 2 */
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tmp11p2 = tmp5p2 + tmp6p2;
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tmp12p2 = tmp6p2 + tmp7p2;
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/* The rotator is modified from fig 4-8 to avoid extra negations. */
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var z5p2 = (tmp10p2 - tmp12p2) * 0.382683433; /* c6 */
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var z2p2 = 0.541196100 * tmp10p2 + z5p2; /* c2-c6 */
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var z4p2 = 1.306562965 * tmp12p2 + z5p2; /* c2+c6 */
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var z3p2 = tmp11p2 * 0.707106781; /* c4 */
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var z11p2 = tmp7p2 + z3p2; /* phase 5 */
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var z13p2 = tmp7p2 - z3p2;
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data[dataOff+40] = z13p2 + z2p2; /* phase 6 */
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data[dataOff+24] = z13p2 - z2p2;
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|
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;
|
|
const I16 = 16;
|
|
const I63 = 63;
|
|
const 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);
|
|
}
|
|
}
|
|
|
|
this.encode = function(image,quality) // image data object
|
|
{
|
|
var time_start = new Date().getTime();
|
|
|
|
if(quality) setQuality(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
|
|
|
|
//return new Uint8Array(byteout);
|
|
return new Buffer(byteout);
|
|
|
|
var jpegDataUri = 'data:image/jpeg;base64,' + btoa(byteout.join(''));
|
|
|
|
byteout = [];
|
|
|
|
// benchmarking
|
|
var duration = new Date().getTime() - time_start;
|
|
//console.log('Encoding time: '+ duration + 'ms');
|
|
//
|
|
|
|
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;
|
|
//console.log('Quality set to: '+quality +'%');
|
|
}
|
|
|
|
function init(){
|
|
var time_start = new Date().getTime();
|
|
if(!quality) quality = 50;
|
|
// Create tables
|
|
initCharLookupTable()
|
|
initHuffmanTbl();
|
|
initCategoryNumber();
|
|
initRGBYUVTable();
|
|
|
|
setQuality(quality);
|
|
var duration = new Date().getTime() - time_start;
|
|
//console.log('Initialization '+ duration + 'ms');
|
|
}
|
|
|
|
init();
|
|
|
|
};
|
|
module.exports = encode;
|
|
|
|
function encode(imgData, qu) {
|
|
if (typeof qu === 'undefined') qu = 50;
|
|
var encoder = new JPEGEncoder(qu);
|
|
var data = encoder.encode(imgData, qu);
|
|
return {
|
|
data: data,
|
|
width: imgData.width,
|
|
height: imgData.height
|
|
};
|
|
}
|
|
|
|
// helper function to get the imageData of an existing image on the current page.
|
|
function getImageDataFromImage(idOrElement){
|
|
var theImg = (typeof(idOrElement)=='string')? document.getElementById(idOrElement):idOrElement;
|
|
var cvs = document.createElement('canvas');
|
|
cvs.width = theImg.width;
|
|
cvs.height = theImg.height;
|
|
var ctx = cvs.getContext("2d");
|
|
ctx.drawImage(theImg,0,0);
|
|
|
|
return (ctx.getImageData(0, 0, cvs.width, cvs.height));
|
|
}
|