32 lines
671 B
Plaintext
32 lines
671 B
Plaintext
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'use strict';
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/* eslint-disable consistent-return */
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var str2arr = require('../common').str2arr;
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var sliceEq = require('../common').sliceEq;
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var readUInt32BE = require('../common').readUInt32BE;
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var SIG_PNG = str2arr('\x89PNG\r\n\x1a\n');
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var SIG_IHDR = str2arr('IHDR');
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module.exports = function (data) {
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if (data.length < 24) return;
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// check PNG signature
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if (!sliceEq(data, 0, SIG_PNG)) return;
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// check that first chunk is IHDR
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if (!sliceEq(data, 12, SIG_IHDR)) return;
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return {
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width: readUInt32BE(data, 16),
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height: readUInt32BE(data, 20),
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type: 'png',
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mime: 'image/png',
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wUnits: 'px',
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hUnits: 'px'
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};
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};
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