57 lines
1.2 KiB
JavaScript
57 lines
1.2 KiB
JavaScript
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"use strict";
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let hasSyncZlib = true;
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let zlib = require("zlib");
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if (!zlib.deflateSync) {
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hasSyncZlib = false;
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}
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let constants = require("./constants");
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let Packer = require("./packer");
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module.exports = function (metaData, opt) {
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if (!hasSyncZlib) {
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throw new Error(
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"To use the sync capability of this library in old node versions, please pin pngjs to v2.3.0"
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);
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}
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let options = opt || {};
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let packer = new Packer(options);
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let chunks = [];
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// Signature
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chunks.push(Buffer.from(constants.PNG_SIGNATURE));
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// Header
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chunks.push(packer.packIHDR(metaData.width, metaData.height));
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if (metaData.gamma) {
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chunks.push(packer.packGAMA(metaData.gamma));
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}
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let filteredData = packer.filterData(
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metaData.data,
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metaData.width,
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metaData.height
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);
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// compress it
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let compressedData = zlib.deflateSync(
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filteredData,
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packer.getDeflateOptions()
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);
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filteredData = null;
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if (!compressedData || !compressedData.length) {
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throw new Error("bad png - invalid compressed data response");
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}
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chunks.push(packer.packIDAT(compressedData));
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// End
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chunks.push(packer.packIEND());
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return Buffer.concat(chunks);
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};
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