| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| const PNG = require('pngjs').PNG; |
| const pixelmatch = require('pixelmatch'); |
| const fs = require('fs'); |
| |
| function readPNG(path) { |
| return new Promise(resolve => { |
| fs.createReadStream(path) |
| .pipe(new PNG()) |
| .on('parsed', function () { |
| resolve({ |
| data: this.data, |
| width: this.width, |
| height: this.height |
| }); |
| }); |
| }); |
| } |
| |
| module.exports = function (expectedShotPath, actualShotPath, threshold = 0.01) { |
| return Promise.all([ |
| readPNG(expectedShotPath), |
| readPNG(actualShotPath) |
| ]).then(([expectedImg, actualImg]) => { |
| let width = expectedImg.width; |
| let height = expectedImg.height; |
| if ( |
| (width !== actualImg.width) |
| || (height !== actualImg.height) |
| ) { |
| throw new Error('Image size not match'); |
| } |
| const diffPNG = new PNG({width, height}); |
| let diffPixelsCount = pixelmatch(expectedImg.data, actualImg.data, diffPNG.data, width, height, {threshold}); |
| let totalPixelsCount = width * height; |
| |
| return { |
| diffRatio: diffPixelsCount / totalPixelsCount, |
| diffPNG |
| }; |
| }); |
| }; |