png-chunk-itxt/dist/index.js

Create or parse a PNG iTXt chunk that stores unicode text data in PNG images

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.decodeSync = decodeSync;
exports.encodeSync = encodeSync;
const zlib_1 = __importDefault(require("zlib"));
const binary_parser_1 = require("binary-parser");
// http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.iTXt
const iTxtChunkParser = new binary_parser_1.Parser()
    .string("keyword", { zeroTerminated: true })
    .uint8("compressionFlag")
    .uint8("compressionMethod")
    .string("languageTag", { zeroTerminated: true })
    .string("translatedKeyword", { zeroTerminated: true })
    .buffer("text", { readUntil: "eof" });
function decodeSync(data) {
    const vars = iTxtChunkParser.parse(data);
    const uncompressedTextBuffer = Boolean(vars.compressionFlag)
        ? zlib_1.default.inflateSync(vars.text)
        : vars.text;
    return {
        keyword: vars.keyword,
        compressionFlag: Boolean(vars.compressionFlag),
        compressionMethod: vars.compressionMethod,
        languageTag: vars.languageTag,
        translatedKeyword: vars.translatedKeyword,
        text: new TextDecoder().decode(uncompressedTextBuffer)
    };
}
function encodeSync(chunk) {
    const encoder = new TextEncoder();
    const encodedText = encoder.encode(chunk.text);
    const compressedTextBuffer = chunk.compressionFlag
        ? zlib_1.default.deflateSync(encodedText)
        : encodedText;
    return Buffer.concat([
        encoder.encode(chunk.keyword),
        Buffer.from([0]),
        Buffer.from([Number(chunk.compressionFlag)]),
        Buffer.from([Number(chunk.compressionMethod)]),
        encoder.encode(chunk.languageTag),
        Buffer.from([0]),
        encoder.encode(chunk.translatedKeyword),
        Buffer.from([0]),
        compressedTextBuffer
    ]);
}
//# sourceMappingURL=index.js.map