如何保留页面上的绘制框和路径刷新mxgraph [英] How to retain drawn boxes and path on page refresh mxgraph
本文介绍了如何保留页面上的绘制框和路径刷新mxgraph的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
刷新页面后，我想保留绘制的boxes和路径.
i want to retain drawn boxes and path once page is refreshed.
我正在使用 mxgraph https://jgraph .github.io/mxgraph/docs/manual.html
问题:完成绘图后，如果我刷新页面刷新，则应保留相同的内容<通过将工程图数据存储到localStorage中来实现strong>工程图.
Question: once the drawing is done, if i do page refresh it should retain the same drawing by storing drawing data into localStorage.
注意::我想获取绘制的canvas的json object，并在刷新页面时从该object重新构造它.
NOTE: i want to get json object of drawn canvas, and re-construct it back from that object on page refresh.
下面的视频演示了如何绘制: https://drive.google.com/file/d/1McTMz3e8I_quOcLGt2CtaQhqif3R31qs/view
https://jgraph.github.io/mxgraph/javascript/examples/editors/images/
<!--
Copyright (c) 2006-2013, JGraph Ltd
Dynamic toolbar example for mxGraph. This example demonstrates changing the
state of the toolbar at runtime.
-->
<html>
<head>
<title>Toolbar example for mxGraph</title>
<!-- Sets the basepath for the library if not in same directory -->
<script type="text/javascript">
mxBasePath = 'https://jgraph.github.io/mxgraph/javascript/src';
</script>
<!-- Loads and initializes the library -->
<script type="text/javascript" src="https://jgraph.github.io/mxgraph/javascript/src/js/mxClient.js"></script>
<!-- Example code -->
<script type="text/javascript">
// Program starts here. Creates a sample graph in the
// DOM node with the specified ID. This function is invoked
// from the onLoad event handler of the document (see below).
function main()
{
// Checks if browser is supported
if (!mxClient.isBrowserSupported())
{
// Displays an error message if the browser is
// not supported.
mxUtils.error('Browser is not supported!', 200, false);
}
else
{
// Defines an icon for creating new connections in the connection handler.
// This will automatically disable the highlighting of the source vertex.
mxConnectionHandler.prototype.connectImage = new mxImage('images/connector.gif', 16, 16);
// Creates the div for the toolbar
var tbContainer = document.createElement('div');
tbContainer.style.position = 'absolute';
tbContainer.style.overflow = 'hidden';
tbContainer.style.padding = '2px';
tbContainer.style.left = '0px';
tbContainer.style.top = '0px';
tbContainer.style.width = '24px';
tbContainer.style.bottom = '0px';
document.body.appendChild(tbContainer);
// Creates new toolbar without event processing
var toolbar = new mxToolbar(tbContainer);
toolbar.enabled = false
// Creates the div for the graph
var container = document.createElement('div');
container.style.position = 'absolute';
container.style.overflow = 'hidden';
container.style.left = '24px';
container.style.top = '0px';
container.style.right = '0px';
container.style.bottom = '0px';
container.style.background = 'url("editors/images/grid.gif")';
document.body.appendChild(container);
// Workaround for Internet Explorer ignoring certain styles
if (mxClient.IS_QUIRKS)
{
document.body.style.overflow = 'hidden';
new mxDivResizer(tbContainer);
new mxDivResizer(container);
}
// Creates the model and the graph inside the container
// using the fastest rendering available on the browser
var model = new mxGraphModel();
var graph = new mxGraph(container, model);
// Enables new connections in the graph
graph.setConnectable(true);
graph.setMultigraph(false);
// Stops editing on enter or escape keypress
var keyHandler = new mxKeyHandler(graph);
var rubberband = new mxRubberband(graph);
var addVertex = function(icon, w, h, style)
{
var vertex = new mxCell(null, new mxGeometry(0, 0, w, h), style);
vertex.setVertex(true);
var img = addToolbarItem(graph, toolbar, vertex, icon);
img.enabled = true;
graph.getSelectionModel().addListener(mxEvent.CHANGE, function()
{
var tmp = graph.isSelectionEmpty();
mxUtils.setOpacity(img, (tmp) ? 100 : 20);
img.enabled = tmp;
});
};
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/rectangle.gif', 100, 40, '');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/rounded.gif', 100, 40, 'shape=rounded');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/ellipse.gif', 40, 40, 'shape=ellipse');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/rhombus.gif', 40, 40, 'shape=rhombus');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/triangle.gif', 40, 40, 'shape=triangle');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/cylinder.gif', 40, 40, 'shape=cylinder');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/actor.gif', 30, 40, 'shape=actor');
}
}
function addToolbarItem(graph, toolbar, prototype, image)
{
// Function that is executed when the image is dropped on
// the graph. The cell argument points to the cell under
// the mousepointer if there is one.
var funct = function(graph, evt, cell, x, y)
{
graph.stopEditing(false);
var vertex = graph.getModel().cloneCell(prototype);
vertex.geometry.x = x;
vertex.geometry.y = y;
graph.addCell(vertex);
graph.setSelectionCell(vertex);
}
// Creates the image which is used as the drag icon (preview)
var img = toolbar.addMode(null, image, function(evt, cell)
{
var pt = this.graph.getPointForEvent(evt);
funct(graph, evt, cell, pt.x, pt.y);
});
// Disables dragging if element is disabled. This is a workaround
// for wrong event order in IE. Following is a dummy listener that
// is invoked as the last listener in IE.
mxEvent.addListener(img, 'mousedown', function(evt)
{
// do nothing
});
// This listener is always called first before any other listener
// in all browsers.
mxEvent.addListener(img, 'mousedown', function(evt)
{
if (img.enabled == false)
{
mxEvent.consume(evt);
}
});
mxUtils.makeDraggable(img, graph, funct);
return img;
}
</script>
</head>
<!-- Calls the main function after the page has loaded. Container is dynamically created. -->
<body onload="main();" >
</body>
</html>
推荐答案
这使用mxgraph的XML编码.您可以在mxGraph的其中一个示例中看到此代码.虽然它不是json，但是很容易变成json，并且可以根据需要进行编辑或保存.现在，它按照您的要求存储在localStorage中.
This uses the XML encoding of mxgraph. You see this code in one of the examples of mxGraph. While it is not json, it is very easy to turn into json, and can be edited or saved as you wish. Now it it stored in localStorage as you asked.
在主函数的末尾(在对addVertex的最后一次调用之后)添加以下行:
Add the following lines at the end of your main function (after the last call to addVertex):
// read state on load
if(window.localStorage.graphState){
var doc = mxUtils.parseXml(window.localStorage.graphState);
var dec = new mxCodec(doc);
dec.decode(doc.documentElement, graph.getModel());
}
// save state on change
graph.getModel().addListener('change',function(){
var codec = new mxCodec();
window.localStorage.graphState = codec.encode(
graph.getModel()
).outerHTML;
});
使用JSON更新
更新2:切换到我自己的自定义html2json和json2html实现，以使答案完全独立
如果确实需要适当的JSON对象，则可以从xml转换为json，然后再转换回json.在下面，您可以看到我对json对象进行了字符串化和解析，但这仅是将其保存在localStorage中所需要的.
If you do need a proper JSON object, you can convert from xml to json and back. Below you can see I stringify and parse the json object, this is only needed to save it in localStorage though.
首先添加这两个函数，以从html/xml转换为json，然后从json转换回html/xml:
First add these two functions to convert from html/xml to json and from json back to html/xml:
function html2json(html){
if(html.nodeType==3){
return {
"tagName":"#text",
"content":html.textContent
}
}
var element = {
"tagName":html.tagName
};
if(html.getAttributeNames().length>0){
element.attributes = html.getAttributeNames().reduce(
function(acc,at){acc[at]=html.getAttribute(at); return acc;},
{}
);
}
if(html.childNodes.length>0){
element.children = Array.from(html.childNodes)
.filter(
function(el){
return el.nodeType!=3
||el.textContent.trim().length>0
})
.map(function(el){return html2json(el);});
}
return element;
}
function json2html(json){
var xmlDoc = document.implementation.createDocument(null, json.tagName);
var addAttributes = function(jsonNode, node){
if(jsonNode.attributes){
Object.keys(jsonNode.attributes).map(
function(name){
node.setAttribute(name,jsonNode.attributes[name]);
}
);
}
}
var addChildren = function(jsonNode,node){
if(jsonNode.children){
jsonNode.children.map(
function(jsonChildNode){
json2htmlNode(jsonChildNode,node);
}
);
}
}
var json2htmlNode = function(jsonNode,parent){
if(jsonNode.tagName=="#text"){
return xmlDoc.createTextNode(jsonNode.content);
}
var node = xmlDoc.createElement(jsonNode.tagName);
addAttributes(jsonNode,node);
addChildren(jsonNode,node);
parent.appendChild(node);
}
addAttributes(json,xmlDoc.firstElementChild);
addChildren(json,xmlDoc.firstElementChild);
return xmlDoc;
}
然后像这样从上面更改我的JavaScript代码片段，以将xml转换为json并返回:
Then change my JavaScript snippet from above like this to transform the xml into json and back:
// read state on load
if(window.localStorage.graphState){
var doc = json2html(JSON.parse(localStorage.graphState));
var dec = new mxCodec(doc);
dec.decode(doc.documentElement, graph.getModel());
}
// save state on change
graph.getModel().addListener('change',function(){
var codec = new mxCodec();
window.localStorage.graphState = JSON.stringify(html2json(codec.encode(
graph.getModel()
)));
});
这篇关于如何保留页面上的绘制框和路径刷新mxgraph的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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