2877a788d7
Bitmap images (PNG & friends) are cached in memory. Note: the cache is not discriminatory and grows constantly. Part of issue #23.
58 lines
1.7 KiB
JavaScript
58 lines
1.7 KiB
JavaScript
var fs = require('fs');
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var os = require('os');
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var path = require('path');
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var phantom = require('phantomjs');
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var childProcess = require('child_process');
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var phantomScript = path.join(__dirname, 'phantomjs-svg2png.js');
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var imgCache = Object.create(null);
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// If available, use the font here.
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var fontPath = './Verbana.ttf';
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try {
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// This happens at startup. Needn't be async.
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var fontBase64 = fs.readFileSync(fontPath, 'base64');
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} catch(e) {}
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module.exports = function (svg, format, out, cb) {
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var cacheIndex = format + svg;
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if (imgCache[cacheIndex] !== undefined) {
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// We own a cache for this svg conversion.
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imgCache[cacheIndex].pipe(out);
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}
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var tmpFile = path.join(os.tmpdir(),
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"svg2img-" + (Math.random()*2147483648|0) + "." + format);
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// Conversion to PNG happens in the phantom script.
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childProcess.execFile(phantom.path, [phantomScript, svg, tmpFile],
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function(err, stdout, stderr) {
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if (stdout) { console.log(stdout); }
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if (stderr) { console.error(stderr); }
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if (err != null) { console.error(err.stack); if (cb) { cb(err); } return; }
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var inStream = fs.createReadStream(tmpFile);
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var cached = [];
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inStream.on('data', function(chunk) {
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cached.push(chunk);
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out.write(chunk);
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});
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// Remove the temporary file after use.
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inStream.on('end', function() {
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out.end();
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imgCache[cacheIndex] = streamFromData(cached);
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fs.unlink(tmpFile, cb);
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});
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});
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};
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// Fake stream from the cache.
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var stream = require('stream');
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function streamFromData(data) {
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var newStream = new stream.Readable();
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newStream._read = function() {
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for (var i = 0; i < data.length; i++) {
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newStream.push(data[i]);
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}
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newStream.push(null)
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};
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return newStream;
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}
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