sometimes the picture will be a little darker and sometimes it will be completely black. I don"t see what"s wrong with the code. I hope God can help me answer
/ /-ID card upload-
//document.getElementById("img").addEventListener("change", function() {
$("-sharpimg_wrapper").on("change",".input_img",function(){
var reader = new FileReader();
var that = this;
var nodeId = $(this).parent().parent().attr("id");
reader.onload = function (e) {
console.log("");
//console.log(e.target.result);
compress(e.target.result, fileSize,nodeId);
compress_show(e.target.result, fileSize,nodeId,that);
};
reader.readAsDataURL(this.files[0]);
var fileSize = Math.round(this.files[0].size / 1024 / 1024); //M
});
/ / Image compression
function compress (res, fileSize,nodeId) {/ / res represents the uploaded picture, and the size of the fileSize-sized picture
console.log("");
var img = new Image(),
maxW = $("-sharpsfzm").width() * 3, //
maxH = $("-sharpsfzm").height() * 3; //
console.log(9999);
img.onload = function() {
var cvs = document.createElement("canvas"),
ctx = cvs.getContext("2d");
if(img.width > maxW) {
img.height *= maxW / img.width;
img.width = maxW;
} else {
img.width *= maxH / img.height;
img.height = maxH;
}
cvs.width = img.width;
cvs.height = img.height;
ctx.clearRect(0, 0, cvs.width, cvs.height);
ctx.drawImage(img, 0, 0, img.width, img.height);
var compressRate = getCompressRate(1, fileSize);
var dataUrl = cvs.toDataURL("image/jpeg", compressRate).replace("data:image/jpeg;base64,","");
selectPicture(nodeId,dataUrl);
console.log(cvs);
}
img.src = res;
}/ / Compression ratio
function getCompressRate(allowMaxSize, fileSize) { //sizeMB
var compressRate = 1;
if(fileSize / allowMaxSize > 4) {
compressRate = 0.5;
} else if(fileSize / allowMaxSize > 3) {
compressRate = 0.6;
} else if(fileSize / allowMaxSize > 2) {
compressRate = 0.7;
} else if(fileSize > allowMaxSize) {
compressRate = 0.8;
} else {
compressRate = 0.9;
}
console.log(compressRate);
return compressRate;
}