all files / lighthouse-core/driver/gatherers/ screenshots.js

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/**
 * @license
 * Copyright 2016 Google Inc. All rights reserved.
 *
 * Licensed 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.
 */
 
'use strict';
 
const Gather = require('./gather');
const DevtoolsTimelineModel = require('../../lib/traces/devtools-timeline-model');
 
class ScreenshotFilmstrip extends Gather {
 
  fetchScreenshot(frame) {
    return frame
      .imageDataPromise()
      .then(data => 'data:image/jpg;base64,' + data);
  }
 
  /**
   * @param {!Array<!Object>} traceData
   * @return {!Promise}
  */
  getScreenshots(traceData) {
    const model = new DevtoolsTimelineModel(traceData);
    const filmStripFrames = model.filmStripModel().frames();
 
    const frameFetches = filmStripFrames.map(frame => this.fetchScreenshot(frame));
    return Promise.all(frameFetches).then(images => {
      return filmStripFrames.map((frame, i) => ({
        timestamp: frame.timestamp,
        datauri: images[i]
      }));
    });
  }
 
  afterPass(options, tracingData) {
    return this.getScreenshots(tracingData.traceContents).then(screenshots => {
      this.artifact = screenshots;
    });
  }
}
 
module.exports = ScreenshotFilmstrip;