1/* 2 * Copyright (c) 2023 Shenzhen Kaihong Digital Industry Development Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16import { screenManager } from '../common/ScreenManager'; 17import { computeSampleSize } from '../utils/ImageUtil'; 18import { UserFileDataItem } from '../base/UserFileDataItem'; 19 20export async function getThumbnail(mediaItem: UserFileDataItem, isCurrent: boolean): Promise<PixelMap> { 21 await mediaItem.load(true); 22 let imgWidth = mediaItem.width; 23 let imgHeight = mediaItem.height; 24 let scale = generateSampleSize(imgWidth, imgHeight, isCurrent); 25 mediaItem.imgWidth = Math.ceil(mediaItem.width / scale); 26 mediaItem.imgHeight = Math.ceil(mediaItem.height / scale); 27 imgWidth = Math.ceil(imgWidth / scale); 28 imgHeight = Math.ceil(imgHeight / scale); 29 return await mediaItem.getThumbnail(imgWidth, imgHeight); 30} 31 32function generateSampleSize(imageWidth: number, imageHeight: number, isCurrent: boolean): number { 33 let width = vp2px(screenManager.getWinWidth()); 34 let height = vp2px(screenManager.getWinHeight()); 35 width = width === 0 ? screenManager.DEFAULT_WIDTH : width; 36 height = height === 0 ? screenManager.DEFAULT_HEIGHT : height; 37 let maxNumOfPixels; 38 if (isCurrent) { 39 maxNumOfPixels = 2 * width * height; 40 } else { 41 maxNumOfPixels = width * height; 42 } 43 let minSide = Math.min(width, height); 44 return computeSampleSize(imageWidth, imageHeight, minSide, maxNumOfPixels); 45}