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bv7_jpeg_encoder

array -> jpeg

此脚本不应直接安装，它是一个供其他脚本使用的外部库。如果您需要使用该库，请在脚本元属性加入：// @require https://update.gf.qytechs.cn/scripts/39476/258527/bv7_jpeg_encoder.js 

  1. // ==UserScript==
  2. // @name         bv7_jpeg_encoder
  3. // @namespace    bv7
  4. // @version      0.1
  5. // @description  array -> jpeg
  6. // @author       bv7
  7. // ==/UserScript==
  8.  
  9. class JpegEncoder {
  10. 	constructor() {
  11. 		this.zigZag = [
  12. 			0x00, 0x01, 0x05, 0x06, 0x0E, 0x0F, 0x1B, 0x1C,
  13. 			0x02, 0x04, 0x07, 0x0D, 0x10, 0x1A, 0x1D, 0x2A,
  14. 			0x03, 0x08, 0x0C, 0x11, 0x19, 0x1E, 0x29, 0x2B,
  15. 			0x09, 0x0B, 0x12, 0x18, 0x1F, 0x28, 0x2C, 0x35,
  16. 			0x0A, 0x13, 0x17, 0x20, 0x27, 0x2D, 0x34, 0x36,
  17. 			0x14, 0x16, 0x21, 0x26, 0x2E, 0x33, 0x37, 0x3C,
  18. 			0x15, 0x22, 0x25, 0x2F, 0x32, 0x38, 0x3B, 0x3D,
  19. 			0x23, 0x24, 0x30, 0x31, 0x39, 0x3A, 0x3E, 0x3F
  20. 		];
  21. 		this.std_dc_luminance_nrcodes = [
  22. 			0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01, 0x01,
  23. 			0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  24. 		];
  25. 		this.std_dc_luminance_values  = [
  26. 			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  27. 			0x08, 0x09, 0x0A, 0x0B
  28. 		];
  29. 		this.std_ac_luminance_nrcodes = [
  30. 			0x00, 0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03,
  31. 			0x05, 0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7D
  32. 		];
  33. 		this.std_ac_luminance_values  = [
  34. 			0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
  35. 			0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
  36. 			0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08,
  37. 			0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1, 0xF0,
  38. 			0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16,
  39. 			0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28,
  40. 			0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
  41. 			0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
  42. 			0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
  43. 			0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
  44. 			0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
  45. 			0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
  46. 			0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
  47. 			0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,
  48. 			0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,
  49. 			0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5,
  50. 			0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4,
  51. 			0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xE1, 0xE2,
  52. 			0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
  53. 			0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
  54. 			0xF9, 0xFA
  55. 		];
  56. 		this.std_dc_chrominance_nrcodes = [
  57. 			0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
  58. 			0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00
  59. 		];
  60. 		this.std_dc_chrominance_values = [
  61. 			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  62. 			0x08, 0x09, 0x0A, 0x0B
  63. 		];
  64. 		this.std_ac_chrominance_nrcodes = [
  65. 			0x00, 0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04,
  66. 			0x07, 0x05, 0x04, 0x04, 0x00, 0x01, 0x02, 0x77
  67. 		];
  68. 		this.std_ac_chrominance_values = [
  69. 			0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
  70. 			0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
  71. 			0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
  72. 			0xA1, 0xB1, 0xC1, 0x09, 0x23, 0x33, 0x52, 0xF0,
  73. 			0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34,
  74. 			0xE1, 0x25, 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26,
  75. 			0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38,
  76. 			0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
  77. 			0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
  78. 			0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
  79. 			0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
  80. 			0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
  81. 			0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96,
  82. 			0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5,
  83. 			0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4,
  84. 			0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3,
  85. 			0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2,
  86. 			0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA,
  87. 			0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9,
  88. 			0xEA, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
  89. 			0xF9, 0xFA
  90. 		];
  91. 		this.YDC_HT          = new Uint8Array(0x0B);
  92. 		this.UVDC_HT         = new Uint8Array(0x0B);
  93. 		this.YAC_HT          = new  Int8Array(0xFA);
  94. 		this.UVAC_HT         = new  Int8Array(0xFA);
  95. 		this.YDC_HT2         = new Uint8Array(0x0B);
  96. 		this.UVDC_HT2        = new Uint8Array(0x0B);
  97. 		this.YAC_HT2         = new Uint8Array(0xFA);
  98. 		this.UVAC_HT2        = new Uint8Array(0xFA);
  99. 		this.YTable          = new  Uint8Array(0x40  );
  100. 		this.UVTable         = new  Uint8Array(0x40  );
  101. 		this.fdtbl_Y         = [];
  102. 		this.fdtbl_UV        = new Float32Array(0x08);
  103. 		this.outputfDCTQuant = new Uint16Array(0x40  );
  104. 		this.DU              = new  Int16Array(0x40  );
  105. 		this.category        = new  Uint8Array(0xFFFE);
  106. 		this.bitcode         = new Uint16Array(0xFFFE);
  107. 		this.RGB_YUV_TABLE   = new Uint32Array(0x0800);
  108. 		this.YDU             = new  Int16Array(0x40  );
  109. 		this.UDU             = new  Int16Array(0x40  );
  110. 		this.VDU             = new  Int16Array(0x40  );
  111. 		this.initHuffmanTbl();
  112. 		this.initCategoryNumber();
  113. 		this.initRGBYUVTable();
  114. 	}
  115. 	// IO functions
  116. 	writeBits(value, posval) {
  117. 		while (posval >= 0) {
  118. 			if (value & (1 << posval)) this.bytenew |= (1 << this.bytepos);
  119. 			posval--;
  120. 			this.bytepos--;
  121. 			if (this.bytepos < 0) {
  122. 				this.writeByte(this.bytenew);
  123. 				if (this.bytenew == 0xFF) this.writeByte(0x00);
  124. 				this.bytepos = 7;
  125. 				this.bytenew = 0;
  126. 			}
  127. 		}
  128. 	}
  129. 	writeByte(value) {
  130. 		this.byteout.push(String.fromCharCode(value)); // write char directly instead of converting later
  131. 	}
  132. 	writeWord(value) {
  133. 		this.writeByte((value >> 8) & 0xFF);
  134.         this.writeByte((value     ) & 0xFF);
  135.     }
  136.     writeAPP0() {
  137.     	this.writeWord(0xFFE0); // marker
  138.     	this.writeWord(0x0010); // length
  139.     	this.writeByte(0x4A  ); // J
  140.     	this.writeByte(0x46  ); // F
  141.     	this.writeByte(0x49  ); // I
  142.     	this.writeByte(0x46  ); // F
  143.     	this.writeByte(0x00  ); // = "JFIF",'\0'
  144.     	this.writeByte(0x01  ); // versionhi
  145.     	this.writeByte(0x01  ); // versionlo
  146.     	this.writeByte(0x00  ); // xyunits
  147.     	this.writeWord(0x0001); // xdensity
  148.     	this.writeWord(0x0001); // ydensity
  149.     	this.writeByte(0x00  ); // thumbnwidth
  150.     	this.writeByte(0x00  ); // thumbnheight
  151.     }
  152. 	writeDQT() {
  153. 		this.writeWord(0xFFDB); // marker
  154. 		this.writeWord(0x0084); // length
  155. 		this.writeByte(0x00  );
  156. 		this.YTable.forEach((v) => this.writeByte(v));
  157.         this.writeByte(0x01  );
  158.         this.UVTable.forEach((v) => this.writeByte(v));
  159.     }
  160. 	writeSOF0(width, height) {
  161. 		this.writeWord(0xFFC0); // marker
  162. 		this.writeWord(0x0011); // length, truecolor YUV JPG
  163. 		this.writeByte(0x08  ); // precision
  164. 		this.writeWord(height);
  165. 		this.writeWord(width );
  166. 		this.writeByte(0x03  ); // nrofcomponents
  167. 		this.writeByte(0x01  ); // IdY
  168. 		this.writeByte(0x11  ); // HVY
  169. 		this.writeByte(0x00  ); // QTY
  170. 		this.writeByte(0x02  ); // IdU
  171. 		this.writeByte(0x11  ); // HVU
  172. 		this.writeByte(0x01  ); // QTU
  173. 		this.writeByte(0x03  ); // IdV
  174. 		this.writeByte(0x11  ); // HVV
  175. 		this.writeByte(0x01  ); // QTV
  176. 	}
  177. 	writeDHT() {
  178. 		this.writeWord(0xFFC4); // marker
  179. 		this.writeWord(0x01A2); // length
  180. 		this.writeByte(0x00  ); // HTYDCinfo
  181. 		this.std_dc_luminance_nrcodes.forEach((v) => this.writeByte(v));
  182. 		this.std_dc_luminance_values.forEach((v) => this.writeByte(v));
  183. 		this.writeByte(0x10  ); // HTYACinfo
  184. 		this.std_ac_luminance_nrcodes.forEach((v) => this.writeByte(v));
  185. 		this.std_ac_luminance_values.forEach((v) => this.writeByte(v));
  186. 		this.writeByte(0x01  ); // HTUDCinfo
  187. 		this.std_dc_chrominance_nrcodes.forEach((v) => this.writeByte(v));
  188. 		this.std_dc_chrominance_values.forEach((v) => this.writeByte(v));
  189. 		this.writeByte(0x11  ); // HTUACinfo
  190. 		this.std_ac_chrominance_nrcodes.forEach((v) => this.writeByte(v));
  191. 		this.std_ac_chrominance_values.forEach((v) => this.writeByte(v));
  192. 	}
  193. 	writeSOS() {
  194. 		this.writeWord(0xFFDA); // marker
  195. 		this.writeWord(0x000C); // length
  196. 		this.writeByte(0x03  ); // nrofcomponents
  197. 		this.writeByte(0x01  ); // IdY
  198. 		this.writeByte(0x00  ); // HTY
  199. 		this.writeByte(0x02  ); // IdU
  200. 		this.writeByte(0x11  ); // HTU
  201. 		this.writeByte(0x03  ); // IdV
  202. 		this.writeByte(0x11  ); // HTV
  203. 		this.writeByte(0x00  ); // Ss
  204. 		this.writeByte(0x3F  ); // Se
  205. 		this.writeByte(0x00  ); // Bf
  206. 	}
  207. 	computeHuffmanTbl(nrcodes, std_table, HT, HT2) {
  208. 		let a, j;
  209. 		let codevalue    = 0;
  210. 		let pos_in_table = 0;
  211. 		nrcodes.forEach((nrcodesK, k) => {
  212. 			for (j = 0; j < nrcodesK; j++) {
  213. 				HT[a = std_table[pos_in_table++]] = codevalue++;
  214. 				HT2[a                           ] = k;
  215. 			}
  216. 			codevalue *= 2;
  217. 		});
  218. 	}
  219. 	initHuffmanTbl() {
  220. 		this.computeHuffmanTbl(this.std_dc_luminance_nrcodes  , this.std_dc_luminance_values  , this.YDC_HT , this.YDC_HT2 );
  221. 		this.computeHuffmanTbl(this.std_dc_chrominance_nrcodes, this.std_dc_chrominance_values, this.UVDC_HT, this.UVDC_HT2);
  222. 		this.computeHuffmanTbl(this.std_ac_luminance_nrcodes  , this.std_ac_luminance_values  , this.YAC_HT , this.YAC_HT2 );
  223. 		this.computeHuffmanTbl(this.std_ac_chrominance_nrcodes, this.std_ac_chrominance_values, this.UVAC_HT, this.UVAC_HT2);
  224. 	}
  225. 	initCategoryNumber() {
  226. 		let cat, nr, nrlower, nrupper, nrn;
  227. 		for (cat = 0, nrlower = 1, nrupper = 2; cat < 15; cat++, nrlower = nrupper, nrupper <<= 1) {
  228. 			for (nr = nrlower, nrn = nrlower - 1; nr < nrupper; nr++, nrn--) { //Positive & Negative numbers
  229. 				this.category[0x7FFF + nr] = this.category[0x7FFF - nr] = cat;
  230. 				this.bitcode[ 0x7FFF + nr] = nr;
  231. 				this.bitcode[ 0x7FFF - nr] = nrn;
  232. 			}
  233. 		}
  234. 	}
  235. 	initRGBYUVTable() {
  236. 		for(let i = 0x0000; i < 0x0100; i++) {
  237. 			this.RGB_YUV_TABLE[i         ] =   0x004C8B * i           ;
  238. 			this.RGB_YUV_TABLE[i + 0x0100] =   0x009646 * i           ;
  239. 			this.RGB_YUV_TABLE[i + 0x0200] =   0x001D2F * i + 0x008000;
  240. 			this.RGB_YUV_TABLE[i + 0x0300] = - 0x002B33 * i           ;
  241. 			this.RGB_YUV_TABLE[i + 0x0400] = - 0x0054CD * i           ;
  242. 			this.RGB_YUV_TABLE[i + 0x0500] =   0x008000 * i + 0x807FFF;
  243. 			this.RGB_YUV_TABLE[i + 0x0600] = - 0x006B2F * i           ;
  244. 			this.RGB_YUV_TABLE[i + 0x0700] = - 0x0014D1 * i           ;
  245. 		}
  246. 	}
  247. 	initQuantTables(sf) {
  248. 		let i, t;
  249. 		let row;
  250. 		let col;
  251. 		[
  252. 			0x10, 0x0B, 0x0A, 0x10, 0x18, 0x28, 0x33, 0x3D,
  253. 			0x0C, 0x0C, 0x0E, 0x13, 0x1A, 0x3A, 0x3C, 0x37,
  254. 			0x0E, 0x0D, 0x10, 0x18, 0x28, 0x39, 0x45, 0x38,
  255. 			0x0E, 0x11, 0x16, 0x1D, 0x33, 0x57, 0x50, 0x3E,
  256. 			0x12, 0x16, 0x25, 0x38, 0x44, 0x6D, 0x67, 0x4D,
  257. 			0x18, 0x23, 0x37, 0x40, 0x51, 0x68, 0x71, 0x5C,
  258. 			0x31, 0x40, 0x4E, 0x57, 0x67, 0x79, 0x78, 0x65,
  259. 			0x48, 0x5C, 0x5F, 0x62, 0x70, 0x64, 0x67, 0x63
  260. 		].forEach((v, i) => this.YTable[this.zigZag[i]] = (t = 0 | ((v * sf + 50) / 100)) < 1 ? 1 : t > 0xFF ? 0xFF : t);
  261. 		[
  262. 			0x11, 0x12, 0x18, 0x2F, 0x63, 0x63, 0x63, 0x63,
  263. 			0x12, 0x15, 0x1A, 0x42, 0x63, 0x63, 0x63, 0x63,
  264. 			0x18, 0x1A, 0x38, 0x63, 0x63, 0x63, 0x63, 0x63,
  265. 			0x2F, 0x42, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  266. 			0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  267. 			0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  268. 			0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  269. 			0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63
  270. 		].forEach((v, i) => this.UVTable[this.zigZag[i]] = (t = 0 | ((v * sf + 50) / 100)) < 1 ? 1 : t > 0xFF ? 0xFF : t);
  271. 		let aasf = [
  272. 			1.0, 1.387039845, 1.306562965, 1.175875602,
  273. 			1.0, 0.785694958, 0.541196100, 0.275899379
  274. 		];
  275. 		for (i = 0, row = 0; row < 8; row++) for (col = 0; col < 8; col++, i++) {
  276. 			this.fdtbl_Y[i]  = 1.0 / (this.YTable [this.zigZag[i]] * aasf[row] * aasf[col] * 8.0);
  277. 			this.fdtbl_UV[i] = 1.0 / (this.UVTable[this.zigZag[i]] * aasf[row] * aasf[col] * 8.0);
  278. 		}
  279.     }
  280. 	fDCTQuant(data, fdtbl) { // DCT & quantization core
  281. 		let d0, d1, d2, d3, d4, d5, d6, d7;
  282. 		let t0, t1, t2, t3, t4, t5, t6, t7;
  283. 		// Pass 1: process rows.
  284. 		let i, p;
  285. 		for (i = p = 0; i < 8; ++i, p += 8) { // advance pointer to next row
  286. 			d0 = data[p    ];
  287. 			d1 = data[p + 1];
  288. 			d2 = data[p + 2];
  289. 			d3 = data[p + 3];
  290. 			d4 = data[p + 4];
  291. 			d5 = data[p + 5];
  292. 			d6 = data[p + 6];
  293. 			d7 = data[p + 7];
  294. 			t0 = d0 + d7;
  295. 			t7 = d0 - d7;
  296. 			t1 = d1 + d6;
  297. 			t6 = d1 - d6;
  298. 			t2 = d2 + d5;
  299. 			t5 = d2 - d5;
  300. 			t3 = d3 + d4;
  301. 			t4 = d3 - d4;
  302. 			// Even part
  303. 			d0          = t0 + t3;    // phase 2
  304. 			d1          = t1 + t2;
  305. 			d2          = t1 - t2;
  306. 			d3          = t0 - t3;
  307. 			data[p    ] = d0 + d1;    // phase 3
  308. 			data[p + 4] = d0 - d1;
  309. 			d0          = (d2 + d3) * 0.707106781; // c4
  310. 			data[p + 2] = d3 + d0;    // phase 5
  311. 			data[p + 6] = d3 - d0;
  312. 			// Odd part
  313. 			d0 = t4 + t5;             // phase 2
  314. 			d1 = t5 + t6;
  315. 			d2 = t6 + t7;
  316. 			// The rotator is modified from fig 4-8 to avoid extra negations.
  317. 			d3          = 0.382683433 * (d0 - d2); // c6
  318. 			t2          = 0.541196100 * d0 + d3;   // c2-c6
  319. 			t4          = 1.306562965 * d2 + d3;   // c2+c6
  320. 			t3          = 0.707106781 * d1     ;   // c4
  321. 			d1          = t7 + t3;    // phase 5
  322. 			d3          = t7 - t3;
  323. 			data[p + 1] = d1 + t4;    // phase 6
  324. 			data[p + 3] = d3 - t2;
  325. 			data[p + 5] = d3 + t2;
  326. 			data[p + 7] = d1 - t4;
  327. 		}
  328. 		// Pass 2: process columns.
  329. 		for (i = p = 0; i < 8; ++i, p++) { // advance pointer to next column
  330. 			d0 = data[p       ];
  331. 			d1 = data[p + 0x08];
  332. 			d2 = data[p + 0x10];
  333. 			d3 = data[p + 0x18];
  334. 			d4 = data[p + 0x20];
  335. 			d5 = data[p + 0x28];
  336. 			d6 = data[p + 0x30];
  337. 			d7 = data[p + 0x38];
  338. 			t0 = d0 + d7;
  339. 			t1 = d1 + d6;
  340. 			t2 = d2 + d5;
  341. 			t3 = d3 + d4;
  342. 			t4 = d3 - d4;
  343. 			t5 = d2 - d5;
  344. 			t6 = d1 - d6;
  345. 			t7 = d0 - d7;
  346. 			// Even part
  347. 			d0             = t0 + t3; // phase 2
  348. 			d1             = t1 + t2;
  349. 			d2             = t1 - t2;
  350. 			d3             = t0 - t3;
  351. 			data[p       ] = d0 + d1; // phase 3
  352. 			data[p + 0x20] = d0 - d1;
  353. 			d0             = (d2 + d3) * 0.707106781; // c4
  354. 			data[p + 0x10] = d3 + d0; // phase 5
  355. 			data[p + 0x30] = d3 - d0;
  356. 			// Odd part
  357. 			d0 = t4 + t5;             // phase 2
  358. 			d1 = t5 + t6;
  359. 			d2 = t6 + t7;
  360. 			// The rotator is modified from fig 4-8 to avoid extra negations.
  361. 			d3             = 0.382683433 * (d0 - d2); // c6
  362. 			t2             = 0.541196100 * d0 + d3;   // c2-c6
  363. 			t4             = 1.306562965 * d2 + d3;   // c2+c6
  364. 			t3             = 0.707106781 * d1;        // c4
  365. 			d1             = t7 + t3; // phase 5
  366. 			d3             = t7 - t3;
  367. 			data[p + 0x08] = d1 + t4; // phase 6
  368. 			data[p + 0x18] = d3 - t2;
  369. 			data[p + 0x28] = d3 + t2;
  370. 			data[p + 0x38] = d1 - t4;
  371. 		}
  372. 		// Quantize/descale the coefficients
  373. 		// Apply the quantization and scaling factor & Round to nearest integer
  374. 		for (i = 0; i < 64; ++i) this.outputfDCTQuant[i] = ((d0 = data[i] * fdtbl[i]) > 0.0) ? ((d0 + 0.5)|0) : ((d0 - 0.5)|0); //outputfDCTQuant[i] = fround(d0);
  375. 		return this.outputfDCTQuant;
  376. 	}
  377. 	processDU(CDU, fdtbl, DC, HTDC, HTAC, HTDC2, HTAC2) {
  378. 		let pos, i, a;
  379. 		let EOB        = HTAC[0x00];
  380. 		let EOB2       = HTAC2[0x00];
  381. 		let M16zeroes  = HTAC[0xF0];
  382. 		let M16zeroes2 = HTAC2[0xF0];
  383. 		let DU_DCT     = this.fDCTQuant(CDU, fdtbl);
  384. 		//ZigZag reorder
  385. 		for (i = 0; i < 64; ++i) this.DU[this.zigZag[i]] = DU_DCT[i];
  386. 		let Diff = this.DU[0] - DC;
  387. 		DC = this.DU[0];
  388. 		//Encode DC
  389. 		if (Diff == 0) this.writeBits(HTDC[0], HTDC2[0]); // Diff might be 0
  390. 		else {
  391. 			pos = 0x7FFF + Diff;
  392. 			this.writeBits(HTDC[a = this.category[pos] + 1], HTDC2[a]);
  393. 			this.writeBits(this.bitcode[pos], this.category[pos]);
  394. 		}
  395. 		//Encode ACs
  396. 		let end0pos = 0x3F; // was const... which is crazy
  397. 		while (end0pos > 0 && this.DU[end0pos] == 0) end0pos--;
  398. 		if (end0pos == 0) this.writeBits(EOB, EOB2); //end0pos = first element in reverse order !=0
  399. 		else {
  400. 			let lng, startpos, nrzeroes, nrmarker;
  401. 			end0pos++;
  402. 			for (i = 1; i < end0pos; i++) {
  403. 				startpos = i;
  404. 				while (this.DU[i] == 0 && i < end0pos) ++i;
  405. 				nrzeroes = i - startpos;
  406. 				if (nrzeroes > 0x0F) {
  407. 					lng = nrzeroes >> 4;
  408. 					for (nrmarker = 0; nrmarker < lng; ++nrmarker) this.writeBits(M16zeroes, M16zeroes2);
  409. 					nrzeroes = nrzeroes & 0x0F;
  410. 				}
  411. 				this.writeBits(HTAC[a = (nrzeroes << 4) + this.category[pos = 0x7FFF + this.DU[i]] + 1], HTAC2[a]);
  412. 				this.writeBits(this.bitcode[pos], this.category[pos]);
  413. 			}
  414. 			if (end0pos != 0x40) this.writeBits(EOB, EOB2);
  415. 		}
  416. 		return DC;
  417. 	}
  418. 	encode(imageData, quality = 0.92) { // image data object
  419. 		this.byteout = []; // Initialize bit writer
  420. 		this.bytenew = 0;
  421. 		this.bytepos = 7;
  422. 		let newSf = Math.floor(quality < 0.5 ? 50 / quality : 200 * (1 - quality));
  423. 		if ((typeof this.sf) == 'undefined' || newSf !== this.sf) this.initQuantTables(this.sf = newSf);
  424. 		// Add JPEG headers
  425. 		this.writeWord(0xFFD8); // SOI
  426. 		this.writeAPP0();
  427. 		this.writeDQT();
  428. 		this.writeSOF0(imageData.width, imageData.height);
  429. 		this.writeDHT();
  430. 		this.writeSOS();
  431. 		let y1, y2, y3, pY3, pY1;
  432. 		let x1, x2, x3, pX3, pX1;
  433. 		let r, g, b;
  434. 		let pos;
  435. 		let quadWidth = imageData.width *  4;
  436. 		let width32   = imageData.width * 32;
  437. 		// Encode 8x8 macroblocks
  438. 		let DCY = 0;
  439. 		let DCU = 0;
  440. 		let DCV = 0;
  441. 		for (y1 = 0, pY1 = 0; y1 < imageData.height; y1 += 8, pY1 += width32) {
  442. 			for (x1 = 0, pX1 = pY1; x1 < imageData.width; x1 += 8, pX1 += 32) {
  443. 				for (y2 = pos = 0, y3 = y1, pY3 = pX1; y2 < 8; y2++, y3++, pY3 += quadWidth) {
  444. 					for (x2 = 0, x3 = x1, pX3 = pY3; x2 < 8; x2++, x3++, pos++) {
  445. 						if (y3 < imageData.height && x3 < imageData.width) {
  446. 							r = imageData.data[pX3++];
  447. 							g = imageData.data[pX3++];
  448. 							b = imageData.data[pX3++];
  449. 							pX3++;
  450. 						} else r = g = b = 0; // padding
  451. 						this.YDU[pos] = ((this.RGB_YUV_TABLE[r         ] + this.RGB_YUV_TABLE[g + 0x0100] + this.RGB_YUV_TABLE[b + 0x0200]) >> 16) - 0x80;
  452. 						this.UDU[pos] = ((this.RGB_YUV_TABLE[r + 0x0300] + this.RGB_YUV_TABLE[g + 0x0400] + this.RGB_YUV_TABLE[b + 0x0500]) >> 16) - 0x80;
  453. 						this.VDU[pos] = ((this.RGB_YUV_TABLE[r + 0x0500] + this.RGB_YUV_TABLE[g + 0x0600] + this.RGB_YUV_TABLE[b + 0x0700]) >> 16) - 0x80;
  454. 					}
  455. 				}
  456. 				DCY = this.processDU(this.YDU, this.fdtbl_Y , DCY,  this.YDC_HT,  this.YAC_HT,  this.YDC_HT2,  this.YAC_HT2);
  457. 				DCU = this.processDU(this.UDU, this.fdtbl_UV, DCU, this.UVDC_HT, this.UVAC_HT, this.UVDC_HT2, this.UVAC_HT2);
  458. 				DCV = this.processDU(this.VDU, this.fdtbl_UV, DCV, this.UVDC_HT, this.UVAC_HT, this.UVDC_HT2, this.UVAC_HT2);
  459. 			}
  460. 		}
  461. 		////////////////////////////////////////////////////////////////
  462. 		// Do the bit alignment of the EOI marker
  463. 		if (this.bytepos >= 0) this.writeBits((1 << (this.bytepos + 1)) - 1, this.bytepos);
  464. 		this.writeWord(0xFFD9); //EOI
  465. 		let res = 'data:image/jpeg;base64,' + btoa(this.byteout.join(''));
  466. 		this.byteout = [];
  467. 		return res;
  468. 	}
  469. }

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