玩一玩GoJS，GoJS是Northwoods Software的产品。Northwoods Software创立于1995年，专注于交互图控件和类库。旗下四款产品：
- GoJS：用于在HTML上创建交互图的纯javaSCript库，GoJS支持复杂的模板定义和数据绑定。
- GoDiagram：用于WinForms的.NET图控件。
- GoXam：用于WPF/Silverlight的图控件。
- JGo：用于Swing/SWT中创建交互图的java库。
试了一下GoJS的BPMN样例，很容易导出SVG或PNG/JPEG等格式的图像数据。其中：
- 由于GoJS是经过代码混淆的，不能对makeSVG方法进行确定的分析，大概是采用HTMLCanvasElement.getContext(‘2d’).drawImage(…).getImageData(…)获得的
- makeImage和makeImageData方法通过HTMLCanvasElement.toDataURL()方法实现的
在控制台执行window.myDiagram.model.toJson()，返回如下结果：
{
"class": "go.GraphLinksModel",
"linkFromPortIdProperty": "fromPort",
"linkToPortIdProperty": "toPort",
"nodeDataArray": [
{
"category": "activity",
"item": "User task",
"key": 7,
"loc": "388.33645784919577 140.35229369949943",
"text": "User Task",
"taskType": 2,
"boundaryEventArray": [
],
"size": "120 80"
},
{
"category": "event",
"item": "End",
"key": 104,
"loc": "569.86545617508 140.90913111767696",
"text": "End",
"eventType": 1,
"eventDimension": 8
},
{
"category": "event",
"item": "start",
"key": 101,
"loc": "183.42028795985397 135.34075693590137",
"text": "Start",
"eventType": 1,
"eventDimension": 1
}
],
"linkDataArray": [
{
"from": 101,
"to": 7,
"fromPort": "",
"toPort": "",
"points": [
204.92028795985,
135.3407569359,
214.92028795985,
135.3407569359,
261.62837290452,
135.3407569359,
261.62837290452,
140.3522936995,
308.3364578492,
140.3522936995,
328.3364578492,
140.3522936995
]
},
{
"from": 7,
"to": 104,
"fromPort": "",
"toPort": "",
"points": [
448.3364578492,
140.3522936995,
458.3364578492,
140.3522936995,
492.60095701214,
140.3522936995,
492.60095701214,
140.90913111768,
526.86545617508,
140.90913111768,
546.86545617508,
140.90913111768
]
}
]
}
(newXMLSerializer()).serializeToString(window.myDiagram.makeSvg())可以获得SVG的字符串表示。