背景：

   由于项目的需要，当用户在查看流程图时，当点击某个流程图片上的节点时，需要提示一些信息，这就需要获取各个节点的信息，此处获取id和name的值。

注意：这个并不是流程图的高亮,即当点击网点申请环节时，获取该节点的id和name,即B001和网点申请，点击部门申请时，获取B002和部门经理审批

解释说明：

1.下方说的x和y:

2.流程定义的key: 即为下方id的值

3.节点的id和name的值：

难点分析：

由 于activiti在部署时，如果没有流程图片，则activiti会自动生成一张图片，而我们项目中使用的是activiti modeler实现的在线画流程图，部署时没有图片，是由activiti自动生成。而activiti在生成图片时，会对图片做一个裁剪操作，所有最终 各个节点的坐标会比实际的要小。

（即：activiti自动生成的图片，会做一个裁剪操作，各个节点实际的x和y的值比xml文件中的要小）

而我们的难点在于，各个节点实际坐标的获取。如下图所示：

即我们实际上获取的坐标需要在减去一个minX和minY，得到的才是我们的各个节点实际的坐标。

步骤分析：

1.根据流程定义的key,重新生成流程图片，而不是获取流程图片。

2.还是根据流程定义的key,获取各个节点的信息。（此处需要注意的是各个节点实际的x和y的值的获取的方法）

3.在jsp页面上使用绝对定位，给点击的节点加上高亮。

步骤实现： 1.根据流程定义的key,重新生成流程图片，而不是获取流程图片。

此处重新生成图片的原因：

因为有些时候我们在部署流程时，将图片也部署进去了，此时使用的就是自己的图片，activiti不会进行图片的裁剪。因为我在下一步获取流程节点的信息时，对x和y的进行了特殊处理，因此此处需要重新生成 流程图片。

/**
* 根据流程的key生成图片
*
* @param request
* @param response
* @param wfKey 流程定义的key
*/
@RequestMapping("/genericImageByWfKey")
public void genericImageByWfKey(HttpServletRequest request, HttpServletResponse response, String wfKey) {
    Context.setProcessEngineConfiguration(processEngineConfiguration);
    RepositoryService repositoryService = this.processEngine.getRepositoryService();
    ProcessDefinition pd = repositoryService.createProcessDefinitionQuery().processDefinitionKey(wfKey).latestVersion().singleResult();
    BpmnModel bm = repositoryService.getBpmnModel(pd.getId());
    InputStream is = ProcessDiagramGenerator.generatePngDiagram(bm); // 生成图片，获取图片的输入流
    try {
        int size = is.available();
        byte data[] = new byte[size];
        is.read(data);
        response.setContentType("image/png"); // 设置返回的文件类型
        OutputStream os = response.getOutputStream();
        os.write(data);
        os.flush();
        os.close();
    } catch (IOException e) {
        log.error("读写流程图时出现异常！");
    }
        log.info("end....");
}

2.还是根据流程定义的key,获取各个节点的信息。

获取各个节点的坐标之前，我们先看一下activiti中是如果获取到最小的x和y的，然后是如何裁剪图片的

2.1获取节点包括线的最小x和最小y :

跟踪acticiti的源码可以发现，最小x和y的获取（org.activiti.engine.impl.bpmn.diagram.ProcessDiagramGenerator.initProcessDiagramCanvas(BpmnModel)）

protected static ProcessDiagramCanvas initProcessDiagramCanvas(BpmnModel bpmnModel) {
    // We need to calculate maximum values to know how big the image will be in its entirety
    double minX = Double.MAX_VALUE;
    double maxX = 0;
    double minY = Double.MAX_VALUE;
    double maxY = 0;

    for (Pool pool : bpmnModel.getPools()) {
      GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(pool.getId());
      minX = graphicInfo.getX();
      maxX = graphicInfo.getX() + graphicInfo.getWidth();
      minY = graphicInfo.getY();
      maxY = graphicInfo.getY() + graphicInfo.getHeight();
    }

    List<FlowNode> flowNodes = gatherAllFlowNodes(bpmnModel);
    for (FlowNode flowNode : flowNodes) {

      GraphicInfo flowNodeGraphicInfo = bpmnModel.getGraphicInfo(flowNode.getId());

      // width
      if (flowNodeGraphicInfo.getX() + flowNodeGraphicInfo.getWidth() > maxX) {
        maxX = flowNodeGraphicInfo.getX() + flowNodeGraphicInfo.getWidth();
      }
      if (flowNodeGraphicInfo.getX() < minX) {
        minX = flowNodeGraphicInfo.getX();
      }
      // height
      if (flowNodeGraphicInfo.getY() + flowNodeGraphicInfo.getHeight() > maxY) {
        maxY = flowNodeGraphicInfo.getY() + flowNodeGraphicInfo.getHeight();
      }
      if (flowNodeGraphicInfo.getY() < minY) {
        minY = flowNodeGraphicInfo.getY();
      }

      for (SequenceFlow sequenceFlow : flowNode.getOutgoingFlows()) {
        List<GraphicInfo> graphicInfoList = bpmnModel.getFlowLocationGraphicInfo(sequenceFlow.getId());
        for (GraphicInfo graphicInfo : graphicInfoList) {
          // width
          if (graphicInfo.getX() > maxX) {
            maxX = graphicInfo.getX();
          }
          if (graphicInfo.getX() < minX) {
            minX = graphicInfo.getX();
          }
          // height
          if (graphicInfo.getY() > maxY) {
            maxY = graphicInfo.getY();
          }
          if (graphicInfo.getY()< minY) {
            minY = graphicInfo.getY();
          }
        }
      }
    }

    int nrOfLanes = 0;
    for (Process process : bpmnModel.getProcesses()) {
      for (Lane l : process.getLanes()) {

        nrOfLanes++;

        GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(l.getId());
        // // width
        if (graphicInfo.getX() + graphicInfo.getWidth() > maxX) {
          maxX = graphicInfo.getX() + graphicInfo.getWidth();
        }
        if (graphicInfo.getX() < minX) {
          minX = graphicInfo.getX();
        }
        // height
        if (graphicInfo.getY() + graphicInfo.getHeight() > maxY) {
          maxY = graphicInfo.getY() + graphicInfo.getHeight();
        }
        if (graphicInfo.getY() < minY) {
          minY = graphicInfo.getY();
        }
      }
    }

    // Special case, see http://jira.codehaus.org/browse/ACT-1431
    if (flowNodes.size() == 0 && bpmnModel.getPools().size() == 0 && nrOfLanes == 0) {
      // Nothing to show
      minX = 0;
      minY = 0;
    }

    return new ProcessDiagramCanvas((int) maxX + 10,(int) maxY + 10, (int) minX, (int) minY);
  }

2.2 图片的裁剪：

还是activiti的源码：（org.activiti.engine.impl.bpmn.diagram.ProcessDiagramCanvas.generateImage(String)）

/**
   * Generates an image of what currently is drawn on the canvas.
   *
   * Throws an {@link ActivitiException} when {@link #close()} is already
   * called.
   */
  public InputStream generateImage(String imageType) {
    if (closed) {
      throw new ActivitiException("ProcessDiagramGenerator already closed");
    }

    ByteArrayOutputStream out = new ByteArrayOutputStream();
    try {
      // Try to remove white space
      minX = (minX <= 5) ? 5 : minX;
      minY = (minY <= 5) ? 5 : minY;
      BufferedImage imageToSerialize = processDiagram;
      if (minX >= 0 && minY >= 0) {
        // 此处的最小x和最小y减去了5
        imageToSerialize = processDiagram.getSubimage(minX - 5, minY - 5, canvasWidth - minX + 5, canvasHeight - minY + 5); // 此处可以看到，activiti对图像做了裁剪的操作。
      }
      ImageIO.write(imageToSerialize, imageType, out);
    } catch (IOException e) {
      throw new ActivitiException("Error while generating process image", e);
    } finally {
      IoUtil.closeSilently(out);
    }
    return new ByteArrayInputStream(out.toByteArray());
  }

2.3 我们自己的各个节点的信息获取

@RequestMapping("/getProcessTrace")
    @ResponseBody
    /**
     * 获取各个节点的具体的信息
     * @param wfKey
     *      流程定义的key
     * @return
     */
    public List<Map<String, Object>> getProcessTrace(String wfKey) throws Exception {
        List<Map<String, Object>> activityInfos = new ArrayList<Map<String, Object>>();
        RepositoryService repositoryService = processEngine.getRepositoryService();
        ProcessDefinition pd = repositoryService.createProcessDefinitionQuery().processDefinitionKey(wfKey).latestVersion().singleResult();
        ProcessDefinitionEntity processDefinition = (ProcessDefinitionEntity) ((RepositoryServiceImpl) repositoryService).getDeployedProcessDefinition(pd.getId());
        List<ActivityImpl> activitiList = processDefinition.getActivities();
        InputStream xmlIs = repositoryService.getResourceAsStream(processDefinition.getDeploymentId(), processDefinition.getResourceName());
        BpmnModel bm = new BpmnXMLConverter().convertToBpmnModel(new InputStreamSource(xmlIs), false, true);

                // 下方使用反射获取最小的x和y，仔细看就会发现调用的是上方2.1节的方法
        Class<?> clazz = Class.forName("org.activiti.engine.impl.bpmn.diagram.ProcessDiagramGenerator");
        Method method = clazz.getDeclaredMethod("initProcessDiagramCanvas", BpmnModel.class);
        method.setAccessible(true);
        ProcessDiagramCanvas pdc = (ProcessDiagramCanvas) method.invoke(clazz.newInstance(), bm); // 调用方法

        clazz = Class.forName("org.activiti.engine.impl.bpmn.diagram.ProcessDiagramCanvas");
        Field minXField = clazz.getDeclaredField("minX"); // 得到minX字段
        Field minYField = clazz.getDeclaredField("minY");
        minXField.setAccessible(true);
        minYField.setAccessible(true);
        int minX = minXField.getInt(pdc);// 最小的x值
        int minY = minYField.getInt(pdc); // 最小的y的值


        minX = minX > 0 ? minX - 5 : 0;   // 此处为什么需要减5，上方2.2中activiti源码中有
        minY = minY > 0 ? minY - 5 : 0;
        for (ActivityImpl activity : activitiList) {
            Map<String, Object> activityInfo = new HashMap<String, Object>();
            activityInfo.put("width", activity.getWidth());
            activityInfo.put("height", activity.getHeight());
            activityInfo.put("x", activity.getX() - minX);
            activityInfo.put("y", activity.getY() - minY);
            activityInfo.put("actId", activity.getId());
            activityInfo.put("name", activity.getProperty("name"));  // ActivityImpl 中没有getName方法，所以此处需要这样获取。
            activityInfos.add(activityInfo);
        }
        return activityInfos;
    }

3.在jsp页面上使用绝对定位，给点击的节点加上高亮。

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Insert title here</title>
        <style type="text/css">
            .activity-attr{border-radius: 10px; border: 3px solid red; transition:ease-out 0.5s; box-shadow:0px 0px 9px red;}
            #processKey{color: red;}
            #flowImageAndRect{position: relative;overflow: scroll;height:300px; heibackground-image: url('${ctx}/resources/images/workflow/grid_10.png')}
            body,html{margin: 0px;padding:0px;}
        </style>
        <script type="text/javascript">
            $(function(){
                var wfKey = '${param.wfKey}'; // 流程定义的key
                var $flowImageAndRect = $('#flowImageAndRect');
                $('#processKey').html('流程定义的key --> ' + wfKey);
                // 加载流程图片
                loadProcessImage(wfKey,$flowImageAndRect);
                // 加载各节点信息，最终实现，在点击图片上的各节点时，出现高亮
                setTimeout(function(){
                    loadProcessTrace(wfKey,$flowImageAndRect);
                },200);

                var $revClickRect = null; // 上次点击的图形
                // 绑定click事件，点击实现，只有点击的不是同一个时，才显示红色的边框（如果多次点击同一个，红色的边框只出现一次）
                $('#flowImageAndRect').off('click').on('click','.activity-attr',function(e){
                    var $this = $(this);
                    var prevFlag = false; // 是上一个图形，避免多次点击同一个
                    if($revClickRect){ // 说明不是第一次点击
                        prevFlag = ($revClickRect.attr('actId')!=$this.attr('actId')) ? false : true;// 说明2次点击的不是同一个
                        if(!prevFlag)
                            $revClickRect.css('opacity','0');
                    }
                    if(!prevFlag){ // 此处可以请求后台，加载相关的数据（多次点击同一个，下方可确保只执行一次）
                        $this.css('opacity','1'); // 显示当前的
                        $revClickRect = $this; // 将当前设置为上次点击的
                        $('#info').html('节点ID --> ' + $this.attr('actId') + "  |  " + "节点名称 --> " + $this.attr('name'));
                    }
                });
            });

            /**
             * 加载图片
             */
            function loadProcessImage(wfKey,$flowImageAndRect){
                var imageUrl = '${ctx}/workflow/monitor/genericImageByWfKey.do?wfKey='+wfKey;
                // 加载图片
                $('<img />',{
                    "src" : imageUrl,
                    "alt" : ''
                }).appendTo($flowImageAndRect);
            }

            /**
             * 加载流程中各节点的信息
             * @param wfKey : 流程定义的key
             * @param $flowImageAndRect
             */
            function loadProcessTrace(wfKey,$flowImageAndRect){
                var traceUrl = '${ctx}/workflow/monitor/getProcessTrace.do?wfKey='+wfKey;
                $.getJSON(traceUrl,function(infos){
                    var html = "";
                    $.each(infos,function(i,v){
                        // 矩形的div
                        var $div = $('<div/>', {
                                'class': 'activity-attr'
                        }).css({
                            position: 'absolute',
                            left: v.x,
                            top: v.y,
                            width: v.width - 3,
                            height:v.height - 3,
                            opacity: 0,
                            zIndex: 100,
                    cursor : 'pointer'
                        }).attr({'actId':v.actId,'name':v.name});
                        html += $div.prop("outerHTML");
                    });
                    $('<div />',{'id':'processRect'}).html(html).appendTo($flowImageAndRect);
                });
            }
        </script>
    </head>
    <body>
        <div id="main">
            <div id="flowImageAndRect">

            </div>

            <div id="processKey" style="font-size: 52px;text-align: center;margin-bottom: 50px;">

            </div>

            <div id="info" style="font-size: 52px;text-align: center;">

            </div>
        </div>
    </body>
</html>

到此，已经完成了。