Javascript 在Electron应用程序中以表单形式下载图像,并通过canvas don'绘制;不行,我能做什么?
我尝试下载表单中的本地图像并用画布绘制,但它不起作用 请帮忙Javascript 在Electron应用程序中以表单形式下载图像,并通过canvas don'绘制;不行,我能做什么?,javascript,electron,Javascript,Electron,我尝试下载表单中的本地图像并用画布绘制,但它不起作用 请帮忙 document.getElementById("download").addEventListener("click", download); //... let link = document.createElement("a"); link.download = `${code.value}.png`; link.href = canvas.toDataURL("image/png").replace("image/png",
document.getElementById("download").addEventListener("click", download);
//...
let link = document.createElement("a");
link.download = `${code.value}.png`;
link.href = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
//...
ctx.save();
ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
ctx.restore();
图像文件:
var imageLoader=document.getElementById('imageLoader');
imageLoader.addEventListener('change',handleImage,false);
var canvas=document.getElementById('imageCanvas');
var ctx=canvas.getContext('2d');
函数handleImage(e){
var reader=new FileReader();
reader.onload=函数(事件){
var img=新图像();
img.onload=函数(){
canvas.width=img.width;
canvas.height=img.height;
ctx.drawImage(img,0,0);
}
img.src=event.target.result;
}
reader.readAsDataURL(e.target.files[0]);
}
<label>Image File:</label><br/>
<input type="file" id="imageLoader" name="imageLoader"/>
<canvas id="imageCanvas"></canvas>
var imageLoader = document.getElementById('imageLoader');
imageLoader.addEventListener('change', handleImage, false);
var canvas = document.getElementById('imageCanvas');
var ctx = canvas.getContext('2d');
function handleImage(e){
var reader = new FileReader();
reader.onload = function(event){
var img = new Image();
img.onload = function(){
canvas.width = img.width;
canvas.height = img.height;
ctx.drawImage(img,0,0);
}
img.src = event.target.result;
}
reader.readAsDataURL(e.target.files[0]);
}