activiti7.1.0.M6（七）获取流程审批图片，高亮显示

/**
     * 根据流程实例Id,获取实时流程图片
     *
     * @param processInstanceId
     * @param
     * @param useCustomColor    true:用自定义的颜色（完成节点绿色，当前节点红色），default:用默认的颜色（红色）
     * @return
     */
    public  void getFlowImgByInstanceId(String processInstanceId, HttpServletResponse response, boolean useCustomColor) {
        try {
            if (org.springframework.util.StringUtils.isEmpty(processInstanceId)) {
                log.error("processInstanceId is null");
                return;
            }
            // 获取历史流程实例
            HistoricProcessInstance historicProcessInstance = historyService
                    .createHistoricProcessInstanceQuery()
                    .processInstanceId(processInstanceId).singleResult();
            // 获取流程中已经执行的节点，按照执行先后顺序排序
            List historicActivityInstances = historyService
                    .createHistoricActivityInstanceQuery()
                    .processInstanceId(processInstanceId)
                    .orderByHistoricActivityInstanceId()
                    .desc().list();
            // 高亮已经执行流程节点ID集合
            List highLightedActivitiIds = new ArrayList<>();
            int index = 1;
            for (HistoricActivityInstance historicActivityInstance : historicActivityInstances) {
                if (useCustomColor) {
                    // 用自定义颜色
                    if (index == historicActivityInstances.size()) {
                        // 当前节点
                        highLightedActivitiIds.add(historicActivityInstance.getActivityId() + "#");
                    } else {
                        // 已完成节点
                        highLightedActivitiIds.add(historicActivityInstance.getActivityId());
                    }
                } else {
                    // 用默认颜色
                    highLightedActivitiIds.add(historicActivityInstance.getActivityId());
                }

                index++;
            }

            ProcessDiagramGenerator processDiagramGenerator = null;
            if (useCustomColor) {
                // 使用自定义的程序图片生成器
                processDiagramGenerator = new CustomProcessDiagramGenerator();

            } else {
                // 使用默认的程序图片生成器
                processDiagramGenerator = new DefaultProcessDiagramGenerator();
            }


            BpmnModel bpmnModel = repositoryService
                    .getBpmnModel(historicProcessInstance.getProcessDefinitionId());
            // 高亮流程已发生流转的线id集合
            List highLightedFlowIds = getHighLightedFlows(bpmnModel, historicActivityInstances);

            // 使用默认配置获得流程图表生成器，并生成追踪图片字符流
            InputStream imageStream = processDiagramGenerator.generateDiagram(bpmnModel,
                    highLightedActivitiIds, highLightedFlowIds, "宋体",
                    "宋体", "宋体");

            // 输出图片内容
            Integer byteSize = 1024;
            byte[] b = new byte[byteSize];
            int len;
            while ((len = imageStream.read(b, 0, byteSize)) != -1) {
                response.getOutputStream().write(b, 0, len);
            }
        } catch (Exception e) {
            log.error("processInstanceId" + processInstanceId + "生成流程图失败，原因：" + e.getMessage(), e);
        }

    }

/**
     * 获取已经流转的线
     *
     * @param bpmnModel
     * @param historicActivityInstances
     * @return
     */
    private static List getHighLightedFlows(BpmnModel bpmnModel,
                                                    List historicActivityInstances) {

        // 流转线ID集合
        List flowIdList = new ArrayList();
        // 全部活动实例
        List historicFlowNodeList = new LinkedList();
        // 已完成的历史活动节点
        List finishedActivityInstanceList = new LinkedList();
        for (HistoricActivityInstance historicActivityInstance : historicActivityInstances) {
            historicFlowNodeList.add((FlowNode) bpmnModel.getMainProcess().getFlowElement(historicActivityInstance.getActivityId(), true));
            if (historicActivityInstance.getEndTime() != null) {
                finishedActivityInstanceList.add(historicActivityInstance);
            }
        }

        // 遍历已完成的活动实例，从每个实例的outgoingFlows中找到已执行的
        FlowNode currentFlowNode = null;
        for (HistoricActivityInstance currentActivityInstance : finishedActivityInstanceList) {
            // 获得当前活动对应的节点信息及outgoingFlows信息
            currentFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(currentActivityInstance.getActivityId(), true);
            List sequenceFlowList = currentFlowNode.getOutgoingFlows();

            /**
             * 遍历outgoingFlows并找到已已流转的
             * 满足如下条件认为已已流转：
             * 1.当前节点是并行网关或包含网关，则通过outgoingFlows能够在历史活动中找到的全部节点均为已流转
             * 2.当前节点是以上两种类型之外的，通过outgoingFlows查找到的时间最近的流转节点视为有效流转
             */
            FlowNode targetFlowNode = null;
            if ("parallelGateway".equals(currentActivityInstance.getActivityType())
                    || "inclusiveGateway".equals(currentActivityInstance.getActivityType())) {
                // 遍历历史活动节点，找到匹配Flow目标节点的
                for (SequenceFlow sequenceFlow : sequenceFlowList) {
                    targetFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(sequenceFlow.getTargetRef(), true);
                    if (historicFlowNodeList.contains(targetFlowNode)
                            && (sequenceFlowList.size() > 1 || Objects.nonNull(currentActivityInstance.getEndTime()))) {
                        flowIdList.add(sequenceFlow.getId());
                    }
                }
            } else {
                // 遍历历史活动节点，找到匹配Flow目标节点的
                for (SequenceFlow sequenceFlow : sequenceFlowList) {
                    for (HistoricActivityInstance historicActivityInstance : historicActivityInstances) {
                        if (historicActivityInstance.getActivityId().equals(sequenceFlow.getTargetRef())) {
                            if(Objects.nonNull(currentActivityInstance.getEndTime())
                                    && Objects.nonNull(historicActivityInstance.getStartTime())){

                                String  endTime = DateUtil.format(currentActivityInstance.getEndTime(), "yyyy-MM-dd HH:mm:ss");
                                String  startTime = DateUtil.format(historicActivityInstance.getStartTime(), "yyyy-MM-dd HH:mm:ss");


                                if(startTime.equals(endTime)){
                                    flowIdList.add(sequenceFlow.getId());
                                }
                            }
                        }
                    }
                }
            }
        }
        return flowIdList;
    }

显示效果如下：