Activiti实现自定义流程图颜色

实现效果：

版本声明：Activiti 5.22.0
需求：Activiti原生代码在展示动态流程图时，仅支持高亮当前节点，且高亮颜色为红色，如何才能实现这样一个需求：要求在展示动态流程图时，走过的历史节点显示为绿色（颜色可配置），当前节点高亮为红色（颜色可配置）？下面讲述下思路。
1、重写ProcessDiagramGenerator接口中的generateDiagram方法，增加color参数：

package com.fengunion.scf.data.workflow.manager;

import java.awt.Color;
import java.io.InputStream;
import java.util.List;
import java.util.Set;

import org.activiti.bpmn.model.BpmnModel;
import org.activiti.image.ProcessDiagramGenerator;

public interface CustomProcessDiagramGeneratorI extends ProcessDiagramGenerator {
    InputStream generateDiagram(BpmnModel bpmnModel, String imageType, List<String> highLightedActivities,
            List<String> highLightedFlows, String activityFontName, String labelFontName, String annotationFontName,
            ClassLoader customClassLoader, double scaleFactor, Color[] colors, Set<String> currIds);
}

2、在Activiti配置中注入自定义的CustomProcessDiagramGeneratorI（此处为SpringBoot方式）：

import java.util.ArrayList;
import java.util.List;

import org.activiti.engine.impl.interceptor.SessionFactory;
import org.activiti.spring.SpringProcessEngineConfiguration;
import org.activiti.spring.boot.ProcessEngineConfigurationConfigurer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;

import com.fengunion.scf.data.workflow.manager.CustomGroupEntityManagerFactory;
import com.fengunion.scf.data.workflow.manager.CustomProcessDiagramGeneratorI;
import com.fengunion.scf.data.workflow.manager.CustomUserEntityManagerFactory;
import com.fengunion.scf.data.workflow.manager.ProcessHistoryManagerSessionFactory;


@Configuration
public class ActivitiConfiguration implements ProcessEngineConfigurationConfigurer{
    
    @Autowired
    private CustomUserEntityManagerFactory customUserEntityManagerFactory;
    
    @Autowired
    private CustomGroupEntityManagerFactory customGroupEntityManagerFactory;
    
    @Autowired
    private ProcessHistoryManagerSessionFactory processHistoryManagerSessionFactory;
    
    @Autowired
    private CustomProcessDiagramGeneratorI customProcessDiagramGeneratorI;
    
    @Override
    public void configure(SpringProcessEngineConfiguration processEngineConfiguration) {
        // TODO Auto-generated method stub
        //processEngineConfiguration.setDataSource(dataSource);
        processEngineConfiguration.setDatabaseSchemaUpdate("none");// none true
        processEngineConfiguration.setDatabaseType("mysql");

        //processEngineConfiguration.setTransactionManager(transactionManager);

        // 流程图字体
        processEngineConfiguration.setActivityFontName("宋体");
        processEngineConfiguration.setAnnotationFontName("宋体");
        processEngineConfiguration.setLabelFontName("宋体");

        processEngineConfiguration.setJpaHandleTransaction(false);
        processEngineConfiguration.setJpaCloseEntityManager(false);
        processEngineConfiguration.setJobExecutorActivate(false);
        processEngineConfiguration.setAsyncExecutorEnabled(false);
//自定义用户和组
        List<SessionFactory> customSessionFactories = new ArrayList<>();
        customSessionFactories.add(customUserEntityManagerFactory);
        customSessionFactories.add(customGroupEntityManagerFactory);
        customSessionFactories.add(processHistoryManagerSessionFactory);
        processEngineConfiguration.setCustomSessionFactories(customSessionFactories);
        
    //自定义流程图样式
    processEngineConfiguration.setProcessDiagramGenerator(customProcessDiagramGeneratorI);
    }
}

3、实现自定义的CustomProcessDiagramGenerator类：

package com.fengunion.scf.data.workflow.manager;

import org.activiti.bpmn.model.*;
import org.activiti.bpmn.model.Process;
import org.activiti.image.impl.DefaultProcessDiagramGenerator;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;

import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.List;
import java.util.Set;

@Component
public class CustomProcessDiagramGenerator extends DefaultProcessDiagramGenerator implements CustomProcessDiagramGeneratorI{
    //预初始化流程图绘制，大大提升了系统启动后首次查看流程图的速度
    static {
        new CustomProcessDiagramCanvas(10,10,0,0,"png", "宋体","宋体","宋体",null);
    }
    
    public CustomProcessDiagramCanvas generateProcessDiagram(BpmnModel bpmnModel, String imageType,
            List<String> highLightedActivities, List<String> highLightedFlows, String activityFontName,
            String labelFontName, String annotationFontName, ClassLoader customClassLoader, double scaleFactor,
            Color [] colors, Set<String> currIds) {
        
        if(null == highLightedActivities) {
            highLightedActivities = Collections.<String>emptyList();
        }
        if(null == highLightedFlows) {
            highLightedFlows = Collections.<String>emptyList();
        }
        
        prepareBpmnModel(bpmnModel);
        
        CustomProcessDiagramCanvas processDiagramCanvas = initProcessDiagramCanvas(bpmnModel, imageType, activityFontName, labelFontName, annotationFontName, customClassLoader);
        
        // Draw pool shape, if process is participant in collaboration
        for (Pool pool : bpmnModel.getPools()) {
          GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(pool.getId());
          processDiagramCanvas.drawPoolOrLane(pool.getName(), graphicInfo);
        }
        
        // Draw lanes
        for (Process process : bpmnModel.getProcesses()) {
          for (Lane lane : process.getLanes()) {
            GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(lane.getId());
            processDiagramCanvas.drawPoolOrLane(lane.getName(), graphicInfo);
          }
        }
        
        // Draw activities and their sequence-flows
        for (Process process: bpmnModel.getProcesses()) {
            List<FlowNode> flowNodeList= process.findFlowElementsOfType(FlowNode.class);
          for (FlowNode flowNode : flowNodeList) {
              drawActivity(processDiagramCanvas, bpmnModel, flowNode, highLightedActivities, highLightedFlows, scaleFactor, colors, currIds);
          }
        }
        
        // Draw artifacts
        for (Process process : bpmnModel.getProcesses()) {
          
          for (Artifact artifact : process.getArtifacts()) {
            drawArtifact(processDiagramCanvas, bpmnModel, artifact);
          }
          
          List<SubProcess> subProcesses = process.findFlowElementsOfType(SubProcess.class, true);
          if (subProcesses != null) {
            for (SubProcess subProcess : subProcesses) {
              for (Artifact subProcessArtifact : subProcess.getArtifacts()) {
                drawArtifact(processDiagramCanvas, bpmnModel, subProcessArtifact);
              }
            }
          }
        }
        
        return processDiagramCanvas;
    }

    protected void drawActivity(CustomProcessDiagramCanvas processDiagramCanvas, BpmnModel bpmnModel, FlowNode flowNode,
            List<String> highLightedActivities, List<String> highLightedFlows, double scaleFactor, Color[] colors, Set<String> currIds) {
        ActivityDrawInstruction drawInstruction = activityDrawInstructions.get(flowNode.getClass());
        if (drawInstruction != null) {
          
          drawInstruction.draw(processDiagramCanvas, bpmnModel, flowNode);

          // Gather info on the multi instance marker
          boolean multiInstanceSequential = false, multiInstanceParallel = false, collapsed = false;
          if (flowNode instanceof Activity) {
            Activity activity = (Activity) flowNode;
            MultiInstanceLoopCharacteristics multiInstanceLoopCharacteristics = activity.getLoopCharacteristics();
            if (multiInstanceLoopCharacteristics != null) {
              multiInstanceSequential = multiInstanceLoopCharacteristics.isSequential();
              multiInstanceParallel = !multiInstanceSequential;
            }
          }

          // Gather info on the collapsed marker
          GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(flowNode.getId()); 
          if (flowNode instanceof SubProcess) {
            collapsed = graphicInfo.getExpanded() != null && !graphicInfo.getExpanded();
          } else if (flowNode instanceof CallActivity) {
            collapsed = true;
          }

          if (scaleFactor == 1.0) {
            // Actually draw the markers
            processDiagramCanvas.drawActivityMarkers((int) graphicInfo.getX(), (int) graphicInfo.getY(),(int) graphicInfo.getWidth(), (int) graphicInfo.getHeight(), 
                    multiInstanceSequential, multiInstanceParallel, collapsed);
          }
          
          // Draw highlighted activities
          if (highLightedActivities.contains(flowNode.getId())) {
              if(!CollectionUtils.isEmpty(currIds)
                      &&currIds.contains(flowNode.getId())
                      && !(flowNode instanceof Gateway)) {//非结束节点，并且是当前节点
                  drawHighLight((flowNode instanceof StartEvent), processDiagramCanvas, bpmnModel.getGraphicInfo(flowNode.getId()), colors[1]); 
              }else {//普通节点
                  drawHighLight((flowNode instanceof StartEvent)||(flowNode instanceof EndEvent),processDiagramCanvas, bpmnModel.getGraphicInfo(flowNode.getId()), colors[0]);
              }         
          }

        }
        
        // Outgoing transitions of activity
        for (SequenceFlow sequenceFlow : flowNode.getOutgoingFlows()) {
            String flowId = sequenceFlow.getId();
          boolean highLighted = (highLightedFlows.contains(flowId));
          String defaultFlow = null;
          if (flowNode instanceof Activity) {
            defaultFlow = ((Activity) flowNode).getDefaultFlow();
          } else if (flowNode instanceof Gateway) {
            defaultFlow = ((Gateway) flowNode).getDefaultFlow();
          }
          
          boolean isDefault = false;
          if (defaultFlow != null && defaultFlow.equalsIgnoreCase(flowId)) {
            isDefault = true;
          }
//        boolean drawConditionalIndicator = sequenceFlow.getConditionExpression() != null && !(flowNode instanceof Gateway);
          
          String sourceRef = sequenceFlow.getSourceRef();
          String targetRef = sequenceFlow.getTargetRef();
          FlowElement sourceElement = bpmnModel.getFlowElement(sourceRef);
          FlowElement targetElement = bpmnModel.getFlowElement(targetRef);
          List<GraphicInfo> graphicInfoList = bpmnModel.getFlowLocationGraphicInfo(flowId);
          if (graphicInfoList != null && graphicInfoList.size() > 0) {
            graphicInfoList = connectionPerfectionizer(processDiagramCanvas, bpmnModel, sourceElement, targetElement, graphicInfoList);
            int xPoints[]= new int[graphicInfoList.size()];
            int yPoints[]= new int[graphicInfoList.size()];
            
            for (int i=1; i<graphicInfoList.size(); i++) {
              GraphicInfo graphicInfo = graphicInfoList.get(i);
              GraphicInfo previousGraphicInfo = graphicInfoList.get(i-1);
              
              if (i == 1) {
                xPoints[0] = (int) previousGraphicInfo.getX();
                yPoints[0] = (int) previousGraphicInfo.getY();
              }
              xPoints[i] = (int) graphicInfo.getX();
              yPoints[i] = (int) graphicInfo.getY();
              
            }
            //画高亮线
            processDiagramCanvas.drawSequenceflow(xPoints, yPoints, false, isDefault, highLighted, scaleFactor, colors[0]);
            
            // Draw sequenceflow label
//          GraphicInfo labelGraphicInfo = bpmnModel.getLabelGraphicInfo(flowId);
//          if (labelGraphicInfo != null) {
//            processDiagramCanvas.drawLabel(sequenceFlow.getName(), labelGraphicInfo, false);
//          }else {//解决流程图连线名称不显示的BUG
                GraphicInfo lineCenter = getLineCenter(graphicInfoList);
                processDiagramCanvas.drawLabel(highLighted, sequenceFlow.getName(), lineCenter, Math.abs(xPoints[1]-xPoints[0]) >= 5);
//          }
          }
        }

     // Nested elements
        if (flowNode instanceof FlowElementsContainer) {
          for (FlowElement nestedFlowElement : ((FlowElementsContainer) flowNode).getFlowElements()) {
            if (nestedFlowElement instanceof FlowNode) {
              drawActivity(processDiagramCanvas, bpmnModel, (FlowNode) nestedFlowElement, 
                  highLightedActivities, highLightedFlows, scaleFactor);
            }
          }
        }
    }
    protected void drawHighLight(boolean isStartOrEnd, CustomProcessDiagramCanvas processDiagramCanvas, GraphicInfo graphicInfo, Color color) {
      processDiagramCanvas.drawHighLight(isStartOrEnd, (int) graphicInfo.getX(), (int) graphicInfo.getY(), (int) graphicInfo.getWidth(), (int) graphicInfo.getHeight(), color);
    }
    
    protected static CustomProcessDiagramCanvas initProcessDiagramCanvas(BpmnModel bpmnModel, String imageType,
              String activityFontName, String labelFontName, String annotationFontName, ClassLoader customClassLoader) {
            
            // 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());
                if (graphicInfoList != null) {
                  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();
                    }
                  }
                }
              }
            }
            
            List<Artifact> artifacts = gatherAllArtifacts(bpmnModel);
            for (Artifact artifact : artifacts) {

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

              List<GraphicInfo> graphicInfoList = bpmnModel.getFlowLocationGraphicInfo(artifact.getId());
              if (graphicInfoList != null) {
                  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 https://activiti.atlassian.net/browse/ACT-1431
            if (flowNodes.isEmpty() && bpmnModel.getPools().isEmpty() && nrOfLanes == 0) {
              // Nothing to show
              minX = 0;
              minY = 0;
            }
            
            return new CustomProcessDiagramCanvas((int) maxX + 10,(int) maxY + 10, (int) minX, (int) minY, 
                imageType, activityFontName, labelFontName, annotationFontName, customClassLoader);
          }

    @Override
    public InputStream generateDiagram(BpmnModel bpmnModel, String imageType, List<String> highLightedActivities,
            List<String> highLightedFlows, String activityFontName, String labelFontName, String annotationFontName,
            ClassLoader customClassLoader, double scaleFactor, Color[] colors, Set<String> currIds) {
        CustomProcessDiagramCanvas customProcessDiagramCanvas = generateProcessDiagram(bpmnModel, imageType, highLightedActivities, highLightedFlows, 
                activityFontName, labelFontName, annotationFontName, customClassLoader, scaleFactor,colors, currIds);
        BufferedImage bufferedImage = customProcessDiagramCanvas.generateBufferedImage(imageType);
        ByteArrayOutputStream bs = new ByteArrayOutputStream();  
        ImageOutputStream imOut;
        try {
            imOut = ImageIO.createImageOutputStream(bs);
            ImageIO.write(bufferedImage, "PNG", imOut);
        } catch (IOException e) {
            e.printStackTrace();
        }  
          
        InputStream is = new ByteArrayInputStream(bs.toByteArray());
        return is;
    }
    @Override
    public InputStream generateDiagram(BpmnModel bpmnModel, String imageType, String activityFontName, String labelFontName, String annotationFontName, ClassLoader customClassLoader) {
        return generateDiagram(bpmnModel, imageType, Collections.<String>emptyList(), Collections.<String>emptyList(), 
            activityFontName, labelFontName, annotationFontName, customClassLoader, 1.0, new Color[] {Color.BLACK, Color.BLACK}, null);
    }
    
}

4、重写DefaultProcessDiagramCanvas类drawHighLight和drawSequenceflow方法，实现走过的历史节点高亮功能：

package com.fengunion.scf.data.workflow.manager;

import java.awt.Color;
import java.awt.Font;
import java.awt.Paint;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.awt.font.FontRenderContext;
import java.awt.font.LineBreakMeasurer;
import java.awt.font.TextAttribute;
import java.awt.font.TextLayout;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.text.AttributedCharacterIterator;
import java.text.AttributedString;

import javax.imageio.ImageIO;

import org.activiti.bpmn.model.AssociationDirection;
import org.activiti.bpmn.model.GraphicInfo;
import org.activiti.image.exception.ActivitiImageException;
import org.activiti.image.impl.DefaultProcessDiagramCanvas;
import org.activiti.image.util.ReflectUtil;

import com.fengunion.scf.data.workflow.common.constant.WorkflowConstants;

public class CustomProcessDiagramCanvas extends DefaultProcessDiagramCanvas {

    protected static Color LABEL_COLOR = new Color(0, 0, 0);

    //font
    protected String activityFontName = "宋体";
    protected String labelFontName = "宋体";
    protected String annotationFontName = "宋体";
    
    private static volatile boolean flag = false;

    public CustomProcessDiagramCanvas(int width, int height, int minX, int minY, String imageType) {
        super(width, height, minX, minY, imageType);
    }

    public CustomProcessDiagramCanvas(int width, int height, int minX, int minY, String imageType,
            String activityFontName, String labelFontName, String annotationFontName, ClassLoader customClassLoader) {
        super(width, height, minX, minY, imageType, activityFontName, labelFontName, annotationFontName,
                customClassLoader);
    }

    public void drawHighLight(boolean isStartOrEnd, int x, int y, int width, int height, Color color) {
        Paint originalPaint = g.getPaint();
        Stroke originalStroke = g.getStroke();

        g.setPaint(color);
        g.setStroke(MULTI_INSTANCE_STROKE);
        if (isStartOrEnd) {// 开始、结束节点画圆
            g.drawOval(x, y, width, height);
        } else {// 非开始、结束节点画圆角矩形
            RoundRectangle2D rect = new RoundRectangle2D.Double(x, y, width, height, 5, 5);
            g.draw(rect);
        }
        g.setPaint(originalPaint);
        g.setStroke(originalStroke);
    }

    public void drawSequenceflow(int[] xPoints, int[] yPoints, boolean conditional, boolean isDefault,
            boolean highLighted, double scaleFactor, Color color) {
        drawConnection(xPoints, yPoints, conditional, isDefault, "sequenceFlow", AssociationDirection.ONE, highLighted,
                scaleFactor, color);
    }

    public void drawConnection(int[] xPoints, int[] yPoints, boolean conditional, boolean isDefault,
            String connectionType, AssociationDirection associationDirection, boolean highLighted, double scaleFactor,
            Color color) {

        Paint originalPaint = g.getPaint();
        Stroke originalStroke = g.getStroke();

        g.setPaint(CONNECTION_COLOR);
        if (connectionType.equals("association")) {
            g.setStroke(ASSOCIATION_STROKE);
        } else if (highLighted) {
            g.setPaint(color);
            g.setStroke(HIGHLIGHT_FLOW_STROKE);
        }

        for (int i = 1; i < xPoints.length; i++) {
            Integer sourceX = xPoints[i - 1];
            Integer sourceY = yPoints[i - 1];
            Integer targetX = xPoints[i];
            Integer targetY = yPoints[i];
            Line2D.Double line = new Line2D.Double(sourceX, sourceY, targetX, targetY);
            g.draw(line);
        }

        if (isDefault) {
            Line2D.Double line = new Line2D.Double(xPoints[0], yPoints[0], xPoints[1], yPoints[1]);
            drawDefaultSequenceFlowIndicator(line, scaleFactor);
        }

        if (conditional) {
            Line2D.Double line = new Line2D.Double(xPoints[0], yPoints[0], xPoints[1], yPoints[1]);
            drawConditionalSequenceFlowIndicator(line, scaleFactor);
        }

        if (associationDirection.equals(AssociationDirection.ONE)
                || associationDirection.equals(AssociationDirection.BOTH)) {
            Line2D.Double line = new Line2D.Double(xPoints[xPoints.length - 2], yPoints[xPoints.length - 2],
                    xPoints[xPoints.length - 1], yPoints[xPoints.length - 1]);
            drawArrowHead(line, scaleFactor);
        }
        if (associationDirection.equals(AssociationDirection.BOTH)) {
            Line2D.Double line = new Line2D.Double(xPoints[1], yPoints[1], xPoints[0], yPoints[0]);
            drawArrowHead(line, scaleFactor);
        }
        g.setPaint(originalPaint);
        g.setStroke(originalStroke);
    }

    public void drawLabel(boolean highLighted, String text, GraphicInfo graphicInfo, boolean centered) {
        float interline = 1.0f;

        // text
        if (text != null && text.length() > 0) {
            Paint originalPaint = g.getPaint();
            Font originalFont = g.getFont();
            if (highLighted) {
                g.setPaint(WorkflowConstants.COLOR_NORMAL);
            } else {
                g.setPaint(LABEL_COLOR);
            }
            g.setFont(new Font(labelFontName, Font.BOLD, 10));

            int wrapWidth = 100;
            int textY = (int) graphicInfo.getY();

            // TODO: use drawMultilineText()
            AttributedString as = new AttributedString(text);
            as.addAttribute(TextAttribute.FOREGROUND, g.getPaint());
            as.addAttribute(TextAttribute.FONT, g.getFont());
            AttributedCharacterIterator aci = as.getIterator();
            FontRenderContext frc = new FontRenderContext(null, true, false);
            LineBreakMeasurer lbm = new LineBreakMeasurer(aci, frc);

            while (lbm.getPosition() < text.length()) {
                TextLayout tl = lbm.nextLayout(wrapWidth);
                textY += tl.getAscent();
                Rectangle2D bb = tl.getBounds();
                double tX = graphicInfo.getX();
                if (centered) {
                    tX += (int) (graphicInfo.getWidth() / 2 - bb.getWidth() / 2);
                }
                tl.draw(g, (float) tX, textY);
                textY += tl.getDescent() + tl.getLeading() + (interline - 1.0f) * tl.getAscent();
            }

            // restore originals
            g.setFont(originalFont);
            g.setPaint(originalPaint);
        }
    }

    @Override
    public BufferedImage generateBufferedImage(String imageType) {
        if (closed) {
            throw new ActivitiImageException("ProcessDiagramGenerator already closed");
        }

        // Try to remove white space
        minX = (minX <= WorkflowConstants.PROCESS_PADDING) ? WorkflowConstants.PROCESS_PADDING : minX;
        minY = (minY <= WorkflowConstants.PROCESS_PADDING) ? WorkflowConstants.PROCESS_PADDING : minY;
        BufferedImage imageToSerialize = processDiagram;
        if (minX >= 0 && minY >= 0) {
            imageToSerialize = processDiagram.getSubimage(
                    minX - WorkflowConstants.PROCESS_PADDING,
                    minY - WorkflowConstants.PROCESS_PADDING, 
                    canvasWidth - minX + WorkflowConstants.PROCESS_PADDING,
                    canvasHeight - minY + WorkflowConstants.PROCESS_PADDING);
        }
        return imageToSerialize;
    }

    @Override
    public void initialize(String imageType) {  
        this.processDiagram = new BufferedImage(canvasWidth, canvasHeight, BufferedImage.TYPE_INT_ARGB);    
        this.g = processDiagram.createGraphics();

        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g.setPaint(Color.black);
        
        Font font = new Font(activityFontName, Font.BOLD, FONT_SIZE);
        g.setFont(font);   
        this.fontMetrics = g.getFontMetrics();      
        
        LABEL_FONT = new Font(labelFontName, Font.ITALIC, 10);
        ANNOTATION_FONT = new Font(annotationFontName, Font.PLAIN, FONT_SIZE);
        //优化加载速度
        if(flag) {
            return;
        }
        try {
            USERTASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/userTask.png", customClassLoader));
            SCRIPTTASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/scriptTask.png", customClassLoader));
            SERVICETASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/serviceTask.png", customClassLoader));
            RECEIVETASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/receiveTask.png", customClassLoader));
            SENDTASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/sendTask.png", customClassLoader));
            MANUALTASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/manualTask.png", customClassLoader));
            BUSINESS_RULE_TASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/businessRuleTask.png", customClassLoader));
            SHELL_TASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/shellTask.png", customClassLoader));
            CAMEL_TASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/camelTask.png", customClassLoader));
            MULE_TASK_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/muleTask.png", customClassLoader));
            
            TIMER_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/timer.png", customClassLoader));
            COMPENSATE_THROW_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/compensate-throw.png", customClassLoader));
            COMPENSATE_CATCH_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/compensate.png", customClassLoader));
            ERROR_THROW_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/error-throw.png", customClassLoader));
            ERROR_CATCH_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/error.png", customClassLoader));
            MESSAGE_THROW_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/message-throw.png", customClassLoader));
            MESSAGE_CATCH_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/message.png", customClassLoader));
            SIGNAL_THROW_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/signal-throw.png", customClassLoader));
            SIGNAL_CATCH_IMAGE = ImageIO.read(ReflectUtil.getResource("org/activiti/icons/signal.png", customClassLoader));
          　flag = true;
        } catch (IOException e) {
          　flag = false;
          　LOGGER.warn("Could not load image for process diagram creation: {}", e.getMessage());
        }  
    }

    
}

总结：核心思想就是重写Activiti生成动态流程图的方法(需要重写画节点、画线的方法)，增加颜色配置参数。
鉴于有小伙伴私信找我要自定义的常量类，现将WorkflowConstants类奉上：

package com.fengunion.scf.data.workflow.common.constant;

import com.google.common.collect.Lists;

import java.awt.Color;
import java.util.List;

/** 
 * 变量类
 *@author jjd 
 **/
public final class WorkflowConstants {
    
    /**businessKey**/
    public static final String WORKLOW_BUSINESS_KEY = "businessKey";
    /**按钮网关**/
    public static final String WAY_TYPE = "wayType";
    /**按钮网关**/
    public static final String WAY_TYPE_PREFIX = "way_type_";
    /**项目id**/
    public static final String PROJECT_ID = "projectId";
    /**核心企业Id变量**/
    public static final String CORE_ENTERPRISE_ID="coreEnterpriseId";
    /**链属企业Id变量**/
    public static final String CHAIN_ENTERPRISE_ID="chainEnterpriseId";
    /**银行企业Id变量**/
    public static final String BANK_ENTERPRISE_ID="bankEnterpriseId";
    /**保理公司Id变量**/
    public static final String BAOLI_ENTERPRISE_ID="baoliEnterpriseId";
    /**立账开立企业Id变量**/
    public static final String START_ENTERPRISE_ID="startEnterpriseId";
    /**立账合作企业Id变量**/
    public static final String PARTNER_ENTERPRISE_ID="partnerEnterpriseId";
    /**母公司企业id**/
    public static final String PARENT_ENTERPRISE_ID="parentEnterpriseId";
    /**指定签收企业id**/
    public static final String RECEIVE_ENTERPRISE_ID ="receiveEnterpriseId";
    /**转出方企业Id变量**/
    public static final String TRANSFER_ENTERPRISE_ID="transEnterpriseId";
    /**指定签收企业id**/
    public static final String AC_TASK_ID ="acTaskId";
    /**企业所有角色**/
    public static final String ENT_ALL_ROLE ="all";
    /**运营所有角色**/
    public static final String OPER_ALL_ROLE ="oper";
    /**流程定义缓存时间**/
    public static final int PROCESS_DEFINITION_CACHE = 60;
    /**流程实例激活**/
    public static final int PROCESS_INSTANCE_ACTIVE = 1;
    
    /**流程实例挂起**/
    public static final int PROCESS_INSTANCE_SUSPEND = 0;
    
    /**读取图片**/
    public static final String READ_IMAGE = "image";

    /**读取xml**/
    public static final String READ_XML = "xml";
    
    /**流程激活**/
    public static final Integer ACTIVE_PROCESSDEFINITION = 1;
    
    /**流程挂起**/
    public static final Integer SUSPEND_PROCESSDEFINITION = 2;
    
    /**流程状态：0-全部，1-正常，2-已挂起**/
    public static final int QUERY_ALL       = 0;
    public static final int QUERY_NORMAL    = 1;
    public static final int QUERY_SUSPENDED = 2;
    
    /**流程实例状态：0-全部，1-正常，2-已删除**/
    public static final int INSTANCE_ALL       = 0;
    public static final int INSTANCE_NOT_DELETED    = 1;
    public static final int INSTANCE_DELETED = 2;
    
    /** 系统管理员ID **/
    public static final String INTERFACE_SYSTEM_ID = "-1";
    /** 系统管理员名称 **/
    public static final String INTERFACE_SYSTEM_NAME = "系统操作";
    
    /** 流程部署类型:1-启动并激活，2-启动即挂起 **/
    public static final int PROCESS_START_ACTIVE = 1;
    public static final int PROCESS_START_SUSPEND = 2;
    
    /** 用于标识流程项目配置信息校验结果：1：新流程，2：新版本， 3：流程类别有误  **/
    public static final int CHECK_NEW_PROCESS = 1;
    public static final int CHECK_NEW_VERSION = 2;
    public static final int CHECK_ERROR_PROCESS_TYPE = 3;
    
    /** 默认网关条件值 **/
    public static final Integer default_GATEWAY_CONDITION_VALUE = 1;
    
    /** 工作流-业务状态表数据类型：1-工作流状态，2-业务状态 **/
    public static final Integer PROCESS_STATUS = 1;
    public static final Integer BIZNESS_STATUS = 2;
    
    /** 新增流程时标识：1-直接保存，2-提示覆盖 **/
    public static final Integer PROCESS_STATUS_SAVE = 1;
    public static final Integer BIZNESS_STATUS_WARN = 2;
    
    /** 模板类型标识：1-新创建或直接导入的模板，2-默认模板生成 **/
    public static final Integer MODEL_TYPE_1 = 1;
    public static final Integer MODEL_TYPE_2 = 2;
    
    /** 查询流程定义标识：1-查询最新版本流程定义，2-查询所有版本 **/
    public static final Integer QUERY_PROCESS_LATEST_VERSION = 1;
    public static final Integer QUERY_PROCESS_ALL_VERSION = 2;
    
    /** 按钮网关 通过1 */
    public static final String WAY_TYPE_PASS = "1";
    /** 按钮网关 驳回或结束0 */
    public static final String WAY_TYPE_REJECT = "0";
    
    /** 按钮网关 退回2 */
    public static final String WAY_TYPE_BACK = "2";
    
    /**任务参数为空**/
    public static final int TASK_CHECK_PARAM_NULL = -1;
    /**任务已办理**/
    public static final int TASK_CHECK_COMPLETED = 1;
    /**无权限办理**/
    public static final int TASK_CHECK_NO_PERMISSIONS= 2;
    /**任务校验通过**/
    public static final int TASK_CHECK_PASS = 0;
    /** 动态流程图颜色定义 **/
    public static final Color COLOR_NORMAL = new Color(0, 205, 0);
    public static final Color COLOR_CURRENT = new Color(255, 0, 0);
    
    /** 定义生成流程图时的边距(像素) **/
    public static final int PROCESS_PADDING = 5;

    /** 定义新版业务进度查询包含的流程类型 **/
    public static final List<ProcessTypeEnum> INCLUDE_PROCEE_TYPE = Lists.newArrayList(
            ProcessTypeEnum.BUILD_ACCOUNT_APPLY,
            ProcessTypeEnum.CREDIT_LETTER_APPLY,
            ProcessTypeEnum.CREDIT_LETTER_TRANSFER,
            ProcessTypeEnum.CREDIT_LETTER_CASH);

}

5、调用画图service层

/**
 * @读取动态流程图
 */
public void readProcessImg(String processInstanceId, HttpServletResponse response) throws IOException {
    if (StringUtils.isBlank(processInstanceId)) {
    　　logger.error("参数为空");
    }
    HistoricProcessInstance processInstance = historyService.createHistoricProcessInstanceQuery()
    .processInstanceId(processInstanceId).singleResult();
    BpmnModel bpmnModel = repositoryService.getBpmnModel(processInstance.getProcessDefinitionId());
    ProcessDefinitionEntity definitionEntity = (ProcessDefinitionEntity) repositoryService
    .getProcessDefinition(processInstance.getProcessDefinitionId());
    List<HistoricActivityInstance> highLightedActivitList = historyService.createHistoricActivityInstanceQuery()
    .processInstanceId(processInstanceId).orderByHistoricActivityInstanceStartTime().asc().list();
    // 高亮环节id集合
    List<String> highLightedActivitis = new ArrayList<String>();
    // 高亮线路id集合
    List<String> highLightedFlows = getHighLightedFlows(bpmnModel, highLightedActivitList);
    for (HistoricActivityInstance tempActivity : highLightedActivitList) {
    　　String activityId = tempActivity.getActivityId();
    　　highLightedActivitis.add(activityId);
    }

    Set<String> currIds = runtimeService.createExecutionQuery().processInstanceId(processInstance.getId()).list()
    .stream().map(e->e.getActivityId()).collect(Collectors.toSet());

    CustomProcessDiagramGeneratorI diagramGenerator = (CustomProcessDiagramGeneratorI) processEngineConfiguration
    .getProcessDiagramGenerator();
    InputStream imageStream = diagramGenerator.generateDiagram(bpmnModel, "png", highLightedActivitis,
    highLightedFlows, "宋体", "宋体", "宋体", null, 1.0, new Color[] { WorkflowConstants.COLOR_NORMAL, WorkflowConstants.COLOR_CURRENT }, currIds);
    // 输出资源内容到相应对象
    byte[] b = new byte[1024];
    int len;
    while ((len = imageStream.read(b, 0, 1024)) != -1) {
    　　response.getOutputStream().write(b, 0, len);
    }
}

6、getHighLightedFlows方法如下：

public static List<String> getHighLightedFlows(BpmnModel bpmnModel, List<HistoricActivityInstance> historicActivityInstances) {
    // 高亮流程已发生流转的线id集合
    List<String> highLightedFlowIds = new ArrayList<>();
    // 全部活动节点
    List<FlowNode> historicActivityNodes = new ArrayList<>();
    // 已完成的历史活动节点
    List<HistoricActivityInstance> finishedActivityInstances = new ArrayList<>();

    for (HistoricActivityInstance historicActivityInstance : historicActivityInstances) {
        FlowNode flowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(historicActivityInstance.getActivityId());
        historicActivityNodes.add(flowNode);
        if (historicActivityInstance.getEndTime() != null) {
            finishedActivityInstances.add(historicActivityInstance);
        }
    }

    FlowNode currentFlowNode = null;
    FlowNode targetFlowNode = null;
    // 遍历已完成的活动实例，从每个实例的outgoingFlows中找到已执行的
    for (HistoricActivityInstance currentActivityInstance : finishedActivityInstances) {
        // 获得当前活动对应的节点信息及outgoingFlows信息
        currentFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(currentActivityInstance.getActivityId());
        List<SequenceFlow> sequenceFlows = 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兼容网关，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查找到的时间最早的流转节点视为有效流转
         */
        if ("parallelGateway".equals(currentActivityInstance.getActivityType()) || "inclusiveGateway".equals(currentActivityInstance.getActivityType())) {
            // 遍历历史活动节点，找到匹配流程目标节点的
            for (SequenceFlow sequenceFlow : sequenceFlows) {
                targetFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(sequenceFlow.getTargetRef());
                if (historicActivityNodes.contains(targetFlowNode)) {
                    highLightedFlowIds.add(targetFlowNode.getId());
                }
            }
        } else {
            List<Map<String, Object>> tempMapList = new ArrayList<>();
            for (SequenceFlow sequenceFlow : sequenceFlows) {
                for (HistoricActivityInstance historicActivityInstance : historicActivityInstances) {
                    if (historicActivityInstance.getActivityId().equals(sequenceFlow.getTargetRef())) {
                        Map<String, Object> map = new HashMap<>();
                        map.put("highLightedFlowId", sequenceFlow.getId());
                        map.put("highLightedFlowStartTime", historicActivityInstance.getStartTime().getTime());
                        tempMapList.add(map);
                    }
                }
            }

            if (!CollectionUtils.isEmpty(tempMapList)) {
                // 遍历匹配的集合，取得开始时间最早的一个
                long earliestStamp = 0L;
                String highLightedFlowId = null;
                for (Map<String, Object> map : tempMapList) {
                    long highLightedFlowStartTime = Long.valueOf(map.get("highLightedFlowStartTime").toString());
                    if (earliestStamp == 0 || earliestStamp >= highLightedFlowStartTime) {
                        highLightedFlowId = map.get("highLightedFlowId").toString();
                        earliestStamp = highLightedFlowStartTime;
                    }
                }

                highLightedFlowIds.add(highLightedFlowId);
            }

        }

    }
    return highLightedFlowIds;
}