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@@ -0,0 +1,121 @@
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+var debug = require('debug')('ylt:imageOptimizer');
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+
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+var Q = require('q');
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+var Imagemin = require('imagemin');
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+var jpegoptim = require('imagemin-jpegoptim');
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+
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+var ImageOptimizer = function() {
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+
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+ var MAX_JPEG_QUALITY = 85;
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+
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+ function optimizeImage(entry) {
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+ var deferred = Q.defer();
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+
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+ var fileSize = entry.weightCheck.body.length;
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+ debug('Current file size is %d', fileSize);
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+
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+ if (isJpeg(entry)) {
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+ debug('File is a JPEG');
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+
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+ // Starting softly with a lossless compression
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+ return compressJpegLosslessly(entry.weightCheck.body)
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+
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+ .then(function(newFile) {
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+ var newFileSize = newFile.contents.length;
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+
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+ debug('JPEG lossless compression complete for %s', entry.url);
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+
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+ if (newFileSize < fileSize) {
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+ entry.weightCheck.lossless = entry.weightCheck.optimized = newFileSize;
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+ entry.weightCheck.isOptimized = false;
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+ debug('Filesize is %d bytes smaller (-%d%)', fileSize - newFileSize, Math.round((fileSize - newFileSize) * 100 / fileSize));
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+ }
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+
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+
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+ // Now let's compress lossy to MAX_JPEG_QUALITY
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+ return compressJpegLossly(entry.weightCheck.body);
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+ })
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+
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+ .then(function(newFile) {
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+ var newFileSize = newFile.contents.length;
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+
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+ debug('JPEG lossy compression complete for %s', entry.url);
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+
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+ if (newFileSize < fileSize) {
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+ entry.weightCheck.lossy = newFileSize;
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+ entry.weightCheck.isOptimized = false;
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+ debug('Filesize is %d bytes smaller (-%d%)', fileSize - newFileSize, Math.round((fileSize - newFileSize) * 100 / fileSize));
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+
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+ if (newFileSize < entry.weightCheck.lossless) {
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+ entry.weightCheck.optimized = newFileSize;
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+ }
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+ }
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+
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+ return entry;
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+ });
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+
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+ } else {
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+ debug('File type is not an optimizable image');
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+ deferred.resolve(entry);
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+ }
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+
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+ return deferred.promise;
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+ }
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+
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+ function isJpeg(entry) {
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+ return entry.isImage && entry.contentType === 'image/jpeg';
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+ }
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+
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+ function compressJpegLosslessly(imageBody) {
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+ var deferred = Q.defer();
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+ var startTime = Date.now();
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+
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+ debug('Starting JPEG lossless compression');
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+
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+ new Imagemin()
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+ .src(imageBody)
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+ .use(Imagemin.jpegtran())
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+ .run(function (err, files) {
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+ if (err) {
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+ deferred.reject(err);
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+ } else {
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+ deferred.resolve(files[0]);
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+ var endTime = Date.now();
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+ debug('compressJpegLosslessly took %d ms', endTime - startTime);
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+ }
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+ });
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+
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+ return deferred.promise;
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+ }
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+
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+ function compressJpegLossly(imageBody) {
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+ var deferred = Q.defer();
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+ var startTime = Date.now();
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+
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+ debug('Starting JPEG lossly compression');
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+
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+ new Imagemin()
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+ .src(imageBody)
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+ .use(jpegoptim({max: MAX_JPEG_QUALITY}))
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+ .run(function (err, files) {
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+ if (err) {
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+ deferred.reject(err);
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+ } else {
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+ deferred.resolve(files[0]);
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+ var endTime = Date.now();
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+ debug('compressJpegLossly took %d ms', endTime - startTime);
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+ }
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+ });
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+
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+ return deferred.promise;
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+ }
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+
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+ return {
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+ //recompressIfImage: recompressIfImage,
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+ optimizeImage: optimizeImage,
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+ compressJpegLosslessly: compressJpegLosslessly,
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+ compressJpegLossly: compressJpegLossly
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+ };
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+};
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+
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+module.exports = new ImageOptimizer();
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