dom节点生成图片
1，业务要求将dom节点生成图片，注意点，移动端dom节点不可以使用%，rem等布局。要是用px来布局，并且使用640的设计稿，适配320px的手机屏幕。要在服务器上才可以，我是用node+express搭建的服务器环境。如果有自己的环境可以直接引用下面代码
2依赖的js:html2canvas.js和canvas2image.js,为了省事我引入jq。
1dom绘制成为canvas————–html2canvas
/*
html2canvas 0.5.0-beta3
Copyright (c) 2016 Niklas von Hertzen
Released under License
*/
!function(e){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=e();else if("function"==typeof define&&define.amd)define([],e);else{var f;"undefined"!=typeof window?f=window:"undefined"!=typeof global?f=global:"undefined"!=typeof self&&(f=self),f.html2canvas=e()}}(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o= 0x80 (not a basic code point)',
'invalid-input': 'Invalid input'
},
/** Convenience shortcuts */
baseMinusTMin = base - tMin,
floor = Math.floor,
stringFromCharCode = String.fromCharCode,
/** Temporary variable */
key;
/*--------------------------------------------------------------------------*/
/**
* A generic error utility function.
* @private
* @param {String} type The error type.
* @returns {Error} Throws a `RangeError` with the applicable error message.
*/
function error(type) {
throw RangeError(errors[type]);
}
/**
* A generic `Array#map` utility function.
* @private
* @param {Array} array The array to iterate over.
* @param {Function} callback The function that gets called for every array
* item.
* @returns {Array} A new array of values returned by the callback function.
*/
function map(array, fn) {
var length = array.length;
while (length--) {
array[length] = fn(array[length]);
}
return array;
}
/**
* A simple `Array#map`-like wrapper to work with domain name strings.
* @private
* @param {String} domain The domain name.
* @param {Function} callback The function that gets called for every
* character.
* @returns {Array} A new string of characters returned by the callback
* function.
*/
function mapDomain(string, fn) {
return map(string.split(regexSeparators), fn).join('.');
}
/**
* Creates an array containing the numeric code points of each Unicode
* character in the string. While JavaScript uses UCS-2 internally,
* this function will convert a pair of surrogate halves (each of which
* UCS-2 exposes as separate characters) into a single code point,
* matching UTF-16.
* @see `punycode.ucs2.encode`
* @see
* @memberOf punycode.ucs2
* @name decode
* @param {String} string The Unicode input string (UCS-2).
* @returns {Array} The new array of code points.
*/
function ucs2decode(string) {
var output = [],
counter = 0,
length = string.length,
value,
extra;
while (counter < length) {
value = string.charCodeAt(counter++);
if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
// high surrogate, and there is a next character
extra = string.charCodeAt(counter++);
if ((extra & 0xFC00) == 0xDC00) { // low surrogate
output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
} else {
// unmatched surrogate; only append this code unit, in case the next
// code unit is the high surrogate of a surrogate pair
output.push(value);
counter--;
}
} else {
output.push(value);
}
}
return output;
}
/**
* Creates a string based on an array of numeric code points.
* @see `punycode.ucs2.decode`
* @memberOf punycode.ucs2
* @name encode
* @param {Array} codePoints The array of numeric code points.
* @returns {String} The new Unicode string (UCS-2).
*/
function ucs2encode(array) {
return map(array, function(value) {
var output = '';
if (value > 0xFFFF) {
value -= 0x10000;
output += stringFromCharCode(value >>> 10 & 0x3FF | 0xD800);
value = 0xDC00 | value & 0x3FF;
}
output += stringFromCharCode(value);
return output;
}).join('');
}
/**
* Converts a basic code point into a digit/integer.
* @see `digitToBasic()`
* @private
* @param {Number} codePoint The basic numeric code point value.
* @returns {Number} The numeric value of a basic code point (for use in
* representing integers) in the range `0` to `base - 1`, or `base` if
* the code point does not represent a value.
*/
function basicToDigit(codePoint) {
if (codePoint - 48 < 10) {
return codePoint - 22;
}
if (codePoint - 65 < 26) {
return codePoint - 65;
}
if (codePoint - 97 < 26) {
return codePoint - 97;
}
return base;
}
/**
* Converts a digit/integer into a basic code point.
* @see `basicToDigit()`
* @private
* @param {Number} digit The numeric value of a basic code point.
* @returns {Number} The basic code point whose value (when used for
* representing integers) is `digit`, which needs to be in the range
* `0` to `base - 1`. If `flag` is non-zero, the uppercase form is
* used; else, the lowercase form is used. The behavior is undefined
* if `flag` is non-zero and `digit` has no uppercase form.
*/
function digitToBasic(digit, flag) {
// 0..25 map to ASCII a..z or A..Z
// 26..35 map to ASCII 0..9
return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
}
/**
* Bias adaptation function as per section 3.4 of RFC 3492.
* http://tools.ietf.org/html/rfc3492#section-3.4
* @private
*/
function adapt(delta, numPoints, firstTime) {
var k = 0;
delta = firstTime ? floor(delta / damp) : delta >> 1;
delta += floor(delta / numPoints);
for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {
delta = floor(delta / baseMinusTMin);
}
return floor(k + (baseMinusTMin + 1) * delta / (delta + skew));
}
/**
* Converts a Punycode string of ASCII-only symbols to a string of Unicode
* symbols.
* @memberOf punycode
* @param {String} input The Punycode string of ASCII-only symbols.
* @returns {String} The resulting string of Unicode symbols.
*/
function decode(input) {
// Don't use UCS-2
var output = [],
inputLength = input.length,
out,
i = 0,
n = initialN,
bias = initialBias,
basic,
j,
index,
oldi,
w,
k,
digit,
t,
/** Cached calculation results */
baseMinusT;
// Handle the basic code points: let `basic` be the number of input code
// points before the last delimiter, or `0` if there is none, then copy
// the first basic code points to the output.
basic = input.lastIndexOf(delimiter);
if (basic < 0) {
basic = 0;
}
for (j = 0; j < basic; ++j) {
// if it's not a basic code point
if (input.charCodeAt(j) >= 0x80) {
error('not-basic');
}
output.push(input.charCodeAt(j));
}
// Main decoding loop: start just after the last delimiter if any basic code
// points were copied; start at the beginning otherwise.
for (index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {
// `index` is the index of the next character to be consumed.
// Decode a generalized variable-length integer into `delta`,
// which gets added to `i`. The overflow checking is easier
// if we increase `i` as we go, then subtract off its starting
// value at the end to obtain `delta`.
for (oldi = i, w = 1, k = base; /* no condition */; k += base) {
if (index >= inputLength) {
error('invalid-input');
}
digit = basicToDigit(input.charCodeAt(index++));
if (digit >= base || digit > floor((maxInt - i) / w)) {
error('overflow');
}
i += digit * w;
t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
if (digit < t) {
break;
}
baseMinusT = base - t;
if (w > floor(maxInt / baseMinusT)) {
error('overflow');
}
w *= baseMinusT;
}
out = output.length + 1;
bias = adapt(i - oldi, out, oldi == 0);
// `i` was supposed to wrap around from `out` to `0`,
// incrementing `n` each time, so we'll fix that now:
if (floor(i / out) > maxInt - n) {
error('overflow');
}
n += floor(i / out);
i %= out;
// Insert `n` at position `i` of the output
output.splice(i++, 0, n);
}
return ucs2encode(output);
}
/**
* Converts a string of Unicode symbols to a Punycode string of ASCII-only
* symbols.
* @memberOf punycode
* @param {String} input The string of Unicode symbols.
* @returns {String} The resulting Punycode string of ASCII-only symbols.
*/
function encode(input) {
var n,
delta,
handledCPCount,
basicLength,
bias,
j,
m,
q,
k,
t,
currentValue,
output = [],
/** `inputLength` will hold the number of code points in `input`. */
inputLength,
/** Cached calculation results */
handledCPCountPlusOne,
baseMinusT,
qMinusT;
// Convert the input in UCS-2 to Unicode
input = ucs2decode(input);
// Cache the length
inputLength = input.length;
// Initialize the state
n = initialN;
delta = 0;
bias = initialBias;
// Handle the basic code points
for (j = 0; j < inputLength; ++j) {
currentValue = input[j];
if (currentValue < 0x80) {
output.push(stringFromCharCode(currentValue));
}
}
handledCPCount = basicLength = output.length;
// `handledCPCount` is the number of code points that have been handled;
// `basicLength` is the number of basic code points.
// Finish the basic string - if it is not empty - with a delimiter
if (basicLength) {
output.push(delimiter);
}
// Main encoding loop:
while (handledCPCount < inputLength) {
// All non-basic code points < n have been handled already. Find the next
// larger one:
for (m = maxInt, j = 0; j < inputLength; ++j) {
currentValue = input[j];
if (currentValue >= n && currentValue < m) {
m = currentValue;
}
}
// Increase `delta` enough to advance the decoder's state to ,
// but guard against overflow
handledCPCountPlusOne = handledCPCount + 1;
if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
error('overflow');
}
delta += (m - n) * handledCPCountPlusOne;
n = m;
for (j = 0; j < inputLength; ++j) {
currentValue = input[j];
if (currentValue < n && ++delta > maxInt) {
error('overflow');
}
if (currentValue == n) {
// Represent delta as a generalized variable-length integer
for (q = delta, k = base; /* no condition */; k += base) {
t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
if (q < t) {
break;
}
qMinusT = q - t;
baseMinusT = base - t;
output.push(
stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))
);
q = floor(qMinusT / baseMinusT);
}
output.push(stringFromCharCode(digitToBasic(q, 0)));
bias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength);
delta = 0;
++handledCPCount;
}
}
++delta;
++n;
}
return output.join('');
}
/**
* Converts a Punycode string representing a domain name to Unicode. Only the
* Punycoded parts of the domain name will be converted, i.e. it doesn't
* matter if you call it on a string that has already been converted to
* Unicode.
* @memberOf punycode
* @param {String} domain The Punycode domain name to convert to Unicode.
* @returns {String} The Unicode representation of the given Punycode
* string.
*/
function toUnicode(domain) {
return mapDomain(domain, function(string) {
return regexPunycode.test(string)
? decode(string.slice(4).toLowerCase())
: string;
});
}
/**
* Converts a Unicode string representing a domain name to Punycode. Only the
* non-ASCII parts of the domain name will be converted, i.e. it doesn't
* matter if you call it with a domain that's already in ASCII.
* @memberOf punycode
* @param {String} domain The domain name to convert, as a Unicode string.
* @returns {String} The Punycode representation of the given domain name.
*/
function toASCII(domain) {
return mapDomain(domain, function(string) {
return regexNonASCII.test(string)
? 'xn--' + encode(string)
: string;
});
}
/*--------------------------------------------------------------------------*/
/** Define the public API */
punycode = {
/**
* A string representing the current Punycode.js version number.
* @memberOf punycode
* @type String
*/
'version': '1.2.4',
/**
* An object of methods to convert from JavaScript's internal character
* representation (UCS-2) to Unicode code points, and back.
* @see
* @memberOf punycode
* @type Object
*/
'ucs2': {
'decode': ucs2decode,
'encode': ucs2encode
},
'decode': decode,
'encode': encode,
'toASCII': toASCII,
'toUnicode': toUnicode
};
/** Expose `punycode` */
// Some AMD build optimizers, like r.js, check for specific condition patterns
// like the following:
if (
typeof define == 'function' &&
typeof define.amd == 'object' &&
define.amd
) {
define('punycode', function() {
return punycode;
});
} else if (freeExports && !freeExports.nodeType) {
if (freeModule) { // in Node.js or RingoJS v0.8.0+
freeModule.exports = punycode;
} else { // in Narwhal or RingoJS v0.7.0-
for (key in punycode) {
punycode.hasOwnProperty(key) && (freeExports[key] = punycode[key]);
}
}
} else { // in Rhino or a web browser
root.punycode = punycode;
}
}(this));
}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],2:[function(_dereq_,module,exports){
var log = _dereq_('./log');
function restoreOwnerScroll(ownerDocument, x, y) {
if (ownerDocument.defaultView && (x !== ownerDocument.defaultView.pageXOffset || y !== ownerDocument.defaultView.pageYOffset)) {
ownerDocument.defaultView.scrollTo(x, y);
}
}
function cloneCanvasContents(canvas, clonedCanvas) {
try {
if (clonedCanvas) {
clonedCanvas.width = canvas.width;
clonedCanvas.height = canvas.height;
clonedCanvas.getContext("2d").putImageData(canvas.getContext("2d").getImageData(0, 0, canvas.width, canvas.height), 0, 0);
}
} catch(e) {
log("Unable to copy canvas content from", canvas, e);
}
}
function cloneNode(node, javascriptEnabled) {
var clone = node.nodeType === 3 ? document.createTextNode(node.nodeValue) : node.cloneNode(false);
var child = node.firstChild;
while(child) {
if (javascriptEnabled === true || child.nodeType !== 1 || child.nodeName !== 'SCRIPT') {
clone.appendChild(cloneNode(child, javascriptEnabled));
}
child = child.nextSibling;
}
if (node.nodeType === 1) {
clone._scrollTop = node.scrollTop;
clone._scrollLeft = node.scrollLeft;
if (node.nodeName === "CANVAS") {
cloneCanvasContents(node, clone);
} else if (node.nodeName === "TEXTAREA" || node.nodeName === "SELECT") {
clone.value = node.value;
}
}
return clone;
}
function initNode(node) {
if (node.nodeType === 1) {
node.scrollTop = node._scrollTop;
node.scrollLeft = node._scrollLeft;
var child = node.firstChild;
while(child) {
initNode(child);
child = child.nextSibling;
}
}
}
module.exports = function(ownerDocument, containerDocument, width, height, options, x ,y) {
var documentElement = cloneNode(ownerDocument.documentElement, options.javascriptEnabled);
var container = containerDocument.createElement("iframe");
container.className = "html2canvas-container";
container.style.visibility = "hidden";
container.style.position = "fixed";
container.style.left = "-10000px";
container.style.top = "0px";
container.style.border = "0";
container.width = width;
container.height = height;
container.scrolling = "no"; // ios won't scroll without it
containerDocument.body.appendChild(container);
return new Promise(function(resolve) {
var documentClone = container.contentWindow.document;
/* Chrome doesn't detect relative background-images assigned in inline
将dom节点生成img图片
必须再服务器上才可以生成
点我生成图片