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js实现GIF动图分解成多帧图片上传

2019-10-24 18:05 2396 查看

在项目中遇到需要支持上传gif图片,并把其分解的帧图片一次展示给用户。话不多说直接上代码

分解gif图片需要使用libgif-js这个库!

1. 引入Git库

import SuperGif from './libgif.js'

2. 分解Gif为png图片

const GifDecomposer = {
structureGifObject (gifFiles, cb) { // gifFiles 获取的文件对象 e.target.files[0]
const gifImg = document.createElement('img');
gifImg.setAttribute('rel:animated_src', URL.createObjectURL(gifFiles));
gifImg.setAttribute('rel:auto_play', '0');
// Modified pictures must be added to the body
document.body.appendChild(gifImg);
// Construction example
var rub = new SuperGif({ gif: gifImg });
rub.load(() => {
var img_list = [];
for (let i=1; i <= rub.get_length(); i++) {
// Traversing through each frame of a GIF instance
rub.move_to(i);
// Converting each frame of canvas into a file object
let cur_file = this.convertCanvasToImage(rub.get_canvas(), gifFiles.name.replace('.gif', '') + `-${i}`)
img_list.push({
file_name: cur_file.name,
url: URL.createObjectURL(cur_file),
file: cur_file,
})
}
cb(img_list)
});
},
dataURLtoFile (dataurl, filename) {
const arr = dataurl.split(',');
const mime = arr[0].match(/:(.*?);/)[1];
const bstr = atob(arr[1]);
var n = bstr.length;
const u8arr = new Uint8Array(n);
while (n--) {
u8arr
 = bstr.charCodeAt(n);
}
return new File([u8arr], filename, {type:mime});
},
convertCanvasToImage (canvas, filename) {
return this.dataURLtoFile(canvas.toDataURL('image/png'), filename);
}
}

3. 上传每一张图片

/**
* costume upload GIF decomposer
*/
const filesImg = function (list, storage, costumeFormat, assetType, handleCostume) {
let proDataList = list.map((item, index) => {
return new Promise(function(resolve, reject) {
let reader = new FileReader();
reader.readAsArrayBuffer(item.file);
reader.onload = () => {
let data = {result: reader.result, type: item.file.type, name: item.file.name}
resolve(data);
};
reader.onerror = (error) => {reject(error)};
})
})
Promise.all(proDataList).then(res => {
res.forEach(item => {
// 上传
})
}).catch(data => {console.log(data)})
}

以上就是本文的全部内容,希望对大家的学习有所帮助

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