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HTML5上传图片，后台使用java

div.certification-item-tips添加hidden类来控制隐藏 --> img...'); //return; }); var oReader = new FileReader(); oReader.onload...var image = new Image(); image.src = e.target.result; image.onload...= this.naturalHeight; if (this.naturalWidth > this.naturalHeight && this.naturalWidth.../ this.naturalWidth; } else if (this.naturalHeight > this.naturalWidth && this.naturalHeight

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详解 JS 压缩图片

file2Image(file, callback) 若想将用户通过本地上传的图片放入缓存并 img 标签显示出来，除了可以利用以上方法转化成的 base64 字符串作为图片 src，还可以直接用 URL...) { var canvas = util.image2Canvas(img); file.width = img.naturalWidth; file.height...= img.naturalHeight; _this.beforeCompress(file, canvas); util.canvas2Blob(canvas, function...var aspectRatio = naturalWidth / naturalHeight;var width = Math.max(options.width, 0) || naturalWidth...(options.width > naturalWidth || options.height > naturalHeight)) { result = file; } 大尺寸 png 格式图片在一些手机上

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jscanvas合成图片实现微信公众号海报功能

img1.src = data[0]; img1.onload = function () {//这步必须,因为图片加载是异步的,必须等图片加载完成才开始下面的这些步骤 ....naturalWidth; c.height = img1.naturalHeight; ctx.rect...= new Image; img2.src = data[1]; img2.onload = function () {//同理,如果是加载图片的话,需要等图片加载出来再下一步...('canvas'), ctx = c.getContext('2d'); c.width = img1.naturalWidth...; c.height = img1.naturalHeight; ctx.rect(0, 0, c.width

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【项目】前端图片裁剪

= null; resolve( Object.assign(event, { naturalWidth: image.naturalWidth..., naturalHeight: image.naturalHeight, imageObj: image,...}; const errored = (event) => { image.onerror = null; console.log("img...加载error", event); reject(event); }; image.onload = loaded; image.onerror = errored..., naturalHeight } = imgInfo; const imgHeight = naturalHeight; const imgWidth = naturalWidth

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【不可思议的CANVAS】画一只会跟着鼠标走的小狗

= new Image(); img.onload = () => resolve(img); img.src = imgPath; }...这样就拿到了所有已onload的img对象，然后就可以拿来画了。..., sheight this.ctx.drawImage(img, 0, 0, img.naturalWidth, img.naturalHeight,..., 0, 0, img.naturalWidth, img.naturalHeight, // dx, dy, dwidth, dheight this.currentX...this.pictureWidth : 0); ctx.drawImage(img, 0, 0, img.naturalWidth, img.naturalHeight,

1.1K2 0

H5上传图片

var fr = new FileReader(); fr.readAsDataURL(file); fr.onload = function(e) { $('img').attr('src',...var img = new Image(); img.src = base64; img.onload = function(){ var canvas = document.createElement...('canvas'); canvas.width = img.naturalWidth; canvas.height = img.naturalHeight; canvas.getContext...("2d").drawImage(img, 0, 0); var compressBase64 = cvs.toDataURL(mime_type, quality / 100); } 上传base64

1.1K1 0

H5上传图片

var fr = new FileReader(); fr.readAsDataURL(file); fr.onload = function(e) { $('img').attr('src',...var img = new Image(); img.src = base64; img.onload = function(){ var canvas = document.createElement...('canvas'); canvas.width = img.naturalWidth; canvas.height = img.naturalHeight; canvas.getContext...("2d").drawImage(img, 0, 0); var compressBase64 = cvs.toDataURL(mime_type, quality / 100); } 上传base64

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canvas保存图片的场景分析(附完整demo)

= new Image() img.crossOrigin = '' // allow cors，这里是camelCase，不是crossorigin let [width...,height] = await new Promise(resolve => { img.onload = function () { // 获取图片的原始尺寸...resolve([img.naturalWidth, img.naturalHeight]) } img.src = src })...所以避免在html里写对应的Img吧。...img crossorigin='' /> 复制代码 canvas的其它使用右键图片保存可参考下面的这篇文章: weworkweplay.com/play/saving…

8602 0

懒就是生产力之图片懒加载

isVueNext = Vue.version.split('.')[0] === '2' const DEFAULT_URL = Options.bgImgUrl || 'https//img.aiyoumi.com...reject) => { let image = new Image() image.src = item.src image.onload...= function() { resolve({ naturalHeight: image.naturalHeight,...naturalWidth: image.naturalWidth, src: item.src }) }

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如何使用FormData上传压缩裁剪后的图片Blob对象

function (resolve, reject) { var reader = new FileReader(); reader.onload...= function () { var img = new Image(); img.onload = function...() { var w = this.naturalWidth; var h = this.naturalHeight..., 0, 0, resizeW, resizeH); var base64Img = canvas.toDataURL(file.type, level...); var arr = base64Img.split(","); resolve(arr[1]);

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教程 | 如何在Tensorflow.js中处理MNIST图像数据

imgRequest const imgRequest = new Promise((resolve, reject) => { img.crossOrigin = ''; img.onload =...() => { img.width = img.naturalWidth; img.height = img.naturalHeight; 该代码初始化了一个 new promise，图像加载成功后该...naturalWidth 和 naturalHeight 指加载图像的原始维度，在计算时可以强制校正图像尺寸。...64 datasetBytesBuffer, i * IMAGESIZE * chunkSize * 4, IMAGESIZE * chunkSize); 66 ctx.drawImage( 67 img..., 0, i * chunkSize, img.width, chunkSize, 0, 0, img.width, 68 chunkSize); 69 70 const imageData = ctx.getImageData

3.3K3 0

使用canvas组合多图

when loaded var img = new Image(); img.crossOrigin =...return reject(new Error('Couldn\'t load image')); }; img.onload...= function () { return resolve(Object.assign({}, source, {img: img}));...{ canvasWidthAndHeight.push({ w: image.img.naturalWidth..., h: image.img.naturalHeight })

8862 0

Seam Carving demo

从github上clone了源码，作者原来是用React写的，我把他改成了angular，同样实现了最基本的功能。下面写一下改写的过程：首先明确下我们需要实现的最基本的功能： 1.图片上传。...和Angular的一些区别：获取Img与Canvas元素 React：通过ref img src={imageSrc} alt="Original" ref={imgRef} style={...imageSrc" alt="Original" /> 另外作者原本提供了Mask的功能，这里为了简单实现，没有实现Mask和图片缩放时删除像素的特效，也没有提供Higher quality 的选项(即使用img.naturalWidth...和img.Width的区别)。...; //srcImg.width; let h = srcImg.naturalHeight;//srcImg.height; const ratio = w / h;

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【前端监控】静态资源测速&错误上报

watchImgError(params) { window.document.addEventListener( 'error', (event) => { const target = event.target...lazySrc) { // 加载完成 complete = true，naturalWidth=0 表示图片没高度，那就是加载失败 if (element.complete &&...element.naturalWidth === 0) { ErrImgList.push(node.src); } } }); } function reportResource...if (ErrImgList.indexOf(name) > -1) { return; } // 上报资源测速数据 }); } 4什么时候上报数据 1、window.onload...上报 window.onload() 会在页面完全载入（包括静态资源完成）后触发，所以在这里可以上报一波 2、监听资源加载再逐个上报前面总体上报了一波之后，动态增加的资源，可以动态单个上报 5基本流程

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利用canvas实现一个抠图小工具

-- 图片处理前后展示 --> 原图： img-container">img id="input-img"> 画布：</...(e) { const file = e.target.files[0]; const reader = new FileReader(); reader.onload = onFileLoad...const url = e.target.value; onFileLoad(url); } // 加载图片数据 function onFileLoad(src) { oImg.onload...) { const width = oCanvas.width = img.naturalWidth || img.width; const height = oCanvas.height...= img.naturalHeight || img.height; const ctx = oCanvas.getContext("2d"); ctx.drawImage(img,

2.9K5 0

cropperjs图片裁剪及数据提交文件流互相转换详解

/cropper.js"> 1 2 初始化图片裁剪 new Cropper(element, options) 1 参数： element: 需要裁剪的图片元素，一般指本地获取到的img...= imgUrl; img.onload = function(){ setCutImg (fileList[0].type); /...cropperPhoto.data.winW - 20; // 手机端两侧10px间距 // 正方形头像裁剪，图片竖图，窄图始终以最小的边居中填充裁剪框 if (imgEle.naturalWidth...> imgEle.naturalHeight) { // 横图 objOpt = { minCropBoxHeight: winW...const reader = new FileReader(); reader.onload = function(evt) { console.log(evt.target.result); };

1.2K1 0

【动效】：刮刮卡

canvas.getContext('2d'); const image = new Image(60, 45); // Using optional size for image image.onload...// Use the intrinsic size of image in CSS pixels for the canvas element canvas.width = this.naturalWidth...; canvas.height = this.naturalHeight; // Will draw the image as 300x227, ignoring the custom...= new Image(); img.onload = function(){ bridgeCanvas.drawImage(img, 0, 0, bridge.width...bridgeCanvas.fillStyle = "red"; bridgeCanvas.fillText("刮我一下", 75, 90); } img.src

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写给新手前端的各种文件上传攻略，从小图片到大文件断点续传

= window.URL.createObjectURL(f); img.onload = function () { //显示要是否这块儿内存...= document.createElement('img'); img.src= obj.fileUrl[0]; img.style.width...=new Image(); img.onload=function(){ console.log('图片原始大小 width*height', this.width, this.height...); if(this.naturalWidth){ console.log('图片原始大小 naturalWidth*naturalHeight', this.naturalWidth..., this.naturalHeight); }else{ console.log('oImg.width*height', this.width, this.height

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你的网页有多快 — 从 DOMReady 到 Element Timing

「FP, FCP 和 LCP」近古时期（指距今 5-2 年左右的 React 纪元），由于各种前端框架（React，Vue 等）雨后春笋似的涌出，加上 Webpack 这种前端构建神器的出现，导致 Web...Element Timing 支持的元素有： img> 元素中的 img> 元素中的 poster image 拥有 background-image 的元素一组文本节点...{x: 236, y: 130, width: 144, height: 28, top: 130, …} // loadTime: 0 // name: "text-paint" // naturalHeight...: 0 // naturalWidth: 0 // renderTime: 10850.899999976158 // startTime: 10850.899999976158 //...-- 无效 --> img1" src="https://img.alicdn.com/tfs

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强大的图片预览组件Viewer.js

&#].*$/,""):""}function q(e,t){var i;return e.naturalWidth?...t(e.naturalWidth,e.naturalHeight):(i=W.createElement("img"),i.onload=function(){t(this.width,this.height...f=r/d:m=s*d,m=Fe(.9*m,n),f=Fe(.9*f,a),c={naturalWidth:n,naturalHeight:a,aspectRatio:d,ratio:m/n,width...,i=e.naturalHeight;C(l,o+" ("+t+" × "+i+")")},!...*e,r=f.naturalHeight*e,i?

4.3K2 0

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