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81 lines
2.1 KiB
81 lines
2.1 KiB
var isFn = require('./isFn');
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var loadImg = require('./loadImg');
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var noop = require('./noop');
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var defaults = require('./defaults');
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var createUrl = require('./createUrl');
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var isStr = require('./isStr');
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exports = function(file, options, cb) {
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if (isFn(options)) {
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cb = options;
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options = {};
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}
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cb = cb || noop;
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options = options || {};
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defaults(options, defOptions);
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options.mimeType = options.mimeType || file.type;
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if (isStr(file)) {
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options.isUrl = true;
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} else {
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file = createUrl(file);
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}
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loadImg(file, function(err, img) {
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if (err) return cb(err);
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compress(img, options, cb);
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});
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};
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function compress(img, options, cb) {
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var canvas = document.createElement('canvas');
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var ctx = canvas.getContext('2d');
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var width = img.width;
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var height = img.height;
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var ratio = width / height;
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var maxWidth = options.maxWidth;
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var maxHeight = options.maxHeight;
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if (options.width || options.height) {
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if (options.width) {
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width = options.width;
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height = width / ratio;
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} else if (options.height) {
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height = options.height;
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width = height * ratio;
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}
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} else {
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if (width > maxWidth) {
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width = maxWidth;
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height = width / ratio;
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}
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if (height > maxHeight) {
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height = maxHeight;
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width = height * ratio;
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}
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}
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width = floor(width);
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height = floor(height);
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canvas.width = width;
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canvas.height = height;
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ctx.drawImage(img, 0, 0, width, height);
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if (URL && options.isUrl) URL.revokeObjectURL(img.src);
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if (canvas.toBlob) {
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try {
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canvas.toBlob(
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function(file) {
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cb(null, file);
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},
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options.mimeType,
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options.quality
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);
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} catch (e) {
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cb(e);
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}
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} else {
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cb(new Error('Canvas toBlob is not supported'));
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}
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}
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var defOptions = {
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maxWidth: Infinity,
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maxHeight: Infinity,
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quality: 0.8
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};
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var floor = Math.floor;
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module.exports = exports;
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