ImageClipboard js粘贴剪切板图片，已测试，可用，可获得base64
具体用到自己项目的时候，拿源码改成自己的库，从写一遍
3个小问题
- onpaste 执行了两遍，一次是图片加载完成，一次是加载图片之前。按说 应该搞两个事件来分别调用
- pasteCatcher 应该是作为一个保底实现，我也没看明白是怎么获取剪切板的图片，怎么就能拿到base64了，反正通过e.clipboardData.items是拿到图片了
- 大哥遍历了整个剪切板的图片，全部走了一遍函数，这性能会不会有点问题，也不知道。
结论
不管怎么说，这个代码能用，别的库，好多都不能用。
index.html
<!DOCTYPE html>
<html>
<head>
<!-- https://github.com/jorgenbs/ImageClipboard/tree/master -->
<script src="ImageClipboard.js"></script>
</head>
<body>
<div id="box">
</div>
<script type="text/javascript">
var clipboard = new ImageClipboard('#box');
//onpaste-callback can also be passed as second argument
//in the constructor above.
clipboard.onpaste = function (base64) {
//do stuff with the pasted image
console.info('clipboard.onpaste')
};
//you can also pass in single DOM-element instead of
//query as the first parameter.
</script>
</body>
</html>
ImageClipboard.js
/*jshint boss:true, laxcomma: true, expr: true*/
!function (name, definition) {
if (typeof module != 'undefined') module.exports = definition;
else if (typeof define == 'function' && define.amd) define(name, definition);
else this[name] = definition;
}('ImageClipboard', function (selector, callback) {
'use strict';
var self = typeof this === 'object' ? this : {};
self.el = null;
self.pasteCatcher = null;
self.clipImage = null;
self.onpaste = null;
self.browserSupport = true;
self.init = function (selector, callback) {
if (typeof selector === "string") {
self.el = document.querySelector(selector);
}
else if (_isElement(selector)) self.el = selector;
else return false;
self.pasteCatcher = null;
self.clipImage = null;
self.onpaste = typeof callback === 'function' ? callback : function () { };
//pasting not supported, make workaround
if (!window.Clipboard) {
self.pasteCatcher = _makePasteCatcher();
}
window.addEventListener('paste', self.pasteHandler);
return self;
};
self.pasteHandler = function (e) {
var items;
if (e.clipboardData && e.clipboardData.items) {
items = e.clipboardData.items;
if (items) {
items = Array.prototype.filter.call(items, function (element) {
return element.type.indexOf("image") >= 0;
});
console.info('items.length', items.length)
Array.prototype.forEach.call(items, function (item) {
var blob = item.getAsFile();
var rdr = new FileReader();
rdr.onloadend = function () {
_loadImage(rdr.result);
};
rdr.readAsDataURL(blob);
});
}
}
else if (self.pasteCatcher) {
//no direct access to clipboardData (firefox)
//use the pastecatcher
setTimeout(function () {
var child = self.pasteCatcher.firstElementChild;
if (child && child.tagName == "IMG") {
_loadImage(child.src);
}
}, 5);
}
};
function _makePasteCatcher() {
var pasteBox = document.createElement("div");
pasteBox.setAttribute("id", "paste_catcher");
pasteBox.setAttribute("contenteditable", "");
pasteBox.style.opacity = 0;
document.body.insertBefore(pasteBox, document.body.firstChild);
pasteBox.focus();
self.el.addEventListener("click", function () { pasteBox.focus(); });
return pasteBox;
}
function _loadImage(source) {
var img = new Image();
self.el.innerHTML = "";
img.onload = function () {
//got picture, display it
var imgContainer = document.createElement("img");
imgContainer.src = img.src;
imgContainer.style.maxHeight = "100%";
imgContainer.style.maxHeight = "100%";
self.el.appendChild(imgContainer);
//empty out the ol' pastecatcher
if (self.pasteCatcher) self.pasteCatcher.innerHTML = "";
self.clipImage = img;
if (typeof self.onpaste === 'function')
self.onpaste(img.src);
};
img.src = source;
self.onpaste.call(self, source.split(",")[1]); //callback(base64, file-type)
}
function _isElement(obj) {
return typeof HTMLElement === "object" ? obj instanceof HTMLElement :
obj && typeof obj === "object" && obj.nodeType === 1 && typeof obj.nodeName === "string";
}
return self.init(selector, callback);
});