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1. DefaultProcessDiagramGenerator

DefaultProcessDiagramGenerator是flowable默认的流程图生成器

该类中定义了各种生成图片和一些画图的方法，还有一些辅助方法（如：获取所有节点）

可以查看源码

2. DefaultProcessDiagramCanvas

DefaultProcessDiagramCanvas ：flowable 提供的默认的流程图画布
类中定义了许多字体、颜色、大小、字体等静态变量，还有bpmn中节点（task，gateway，event，flow…）的基本行程，以及各类事件的图标

initialize方法，还有用来画各种节点、连线、事件等等的方法
可以查看源码

3. 使用Flowable默认的流程图生成器

/** * 流程申请 流转图片输入流 */
public void getFlowDiagram(String procInsId){ 

String procDefId;
ProcessInstance processInstance = runtimeService.createProcessInstanceQuery()
.processInstanceId(procInsId)
.singleResult();
if (processInstance == null) { 

HistoricProcessInstance historicProcessInstance = historyService.createHistoricProcessInstanceQuery().processInstanceId(procInsId).singleResult();
procDefId = historicProcessInstance.getProcessDefinitionId();
} else { 

procDefId = processInstance.getProcessDefinitionId();
}
BpmnModel bpmnModel = repositoryService.getBpmnModel(procDefId);
DefaultProcessDiagramGenerator defaultProcessDiagramGenerator = new DefaultProcessDiagramGenerator(); // 创建默认的流程图生成器
String imageType = "png"; // 生成图片的类型
List<String> highLightedActivities = new ArrayList<>(); // 高亮节点集合
List<String> highLightedFlows = new ArrayList<>(); // 高亮连线集合
List<HistoricActivityInstance> hisActInsList = historyService.createHistoricActivityInstanceQuery()
.processInstanceId(procInsId)
.list(); // 查询所有历史节点信息
hisActInsList.forEach(historicActivityInstance -> { 
 // 遍历
if("sequenceFlow".equals(historicActivityInstance.getActivityType())) { 

// 添加高亮连线
highLightedFlows.add(historicActivityInstance.getActivityId());
} else { 

// 添加高亮节点
highLightedActivities.add(historicActivityInstance.getActivityId());
}
});
String activityFontName = "宋体"; // 节点字体
String labelFontName = "微软雅黑"; // 连线标签字体
String annotationFontName = "宋体"; // 连线标签字体
ClassLoader customClassLoader = null; // 类加载器
double scaleFactor = 1.0d; // 比例因子，默认即可
boolean drawSequenceFlowNameWithNoLabelDI = true; // 不设置连线标签不会画
// 生成图片
InputStream inputStream = defaultProcessDiagramGenerator.generateDiagram(bpmnModel, imageType, highLightedActivities 
, highLightedFlows, activityFontName, labelFontName, annotationFontName, customClassLoader,
scaleFactor, drawSequenceFlowNameWithNoLabelDI); // 获取输入流
/* try { // 先将图片保存 FileUtils.copyInputStreamToFile(inputStream, new File("E:\\", "1.png")); } catch (IOException e) { e.printStackTrace(); } */
// 直接写到页面，要先获取HttpServletResponse
byte[] bytes = IoUtil.readInputStream(inputStream, "flow diagram inputStream");
response.setContentType("image/png");
ServletOutputStream outputStream = response.getOutputStream();
response.reset();
outputStream.write(bytes);
outputStream.flush();
outputStream.close();
}

4. 自定义流程图生成器

4.1 扩展DefaultProcessDiagramCanvas

想画什么只需要覆盖掉DefaultProcessDiagramCanvas中的那个方法即可

package top.theonly.workflow.image;
import org.flowable.bpmn.model.AssociationDirection;
import org.flowable.bpmn.model.GraphicInfo;
import org.flowable.image.impl.DefaultProcessDiagramCanvas;
import java.awt.*;
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.text.AttributedCharacterIterator;
import java.text.AttributedString;
public class MyDefaultProcessDiagramCanvas extends DefaultProcessDiagramCanvas { 

//设置高亮线的颜色 这里我设置成绿色
protected static Color HIGHLIGHT_SEQUENCEFLOW_COLOR = Color.GREEN;
//设置连接线（网关）的条件字体颜色 这里我设置成绿色
protected static Color LABEL_COLOR = new Color(10, 176, 213);
public MyDefaultProcessDiagramCanvas(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 MyDefaultProcessDiagramCanvas(int width, int height, int minX, int minY, String imageType) { 

super(width, height, minX, minY, imageType);
}
/** * 画线颜色设置 * @param xPoints * @param yPoints * @param conditional * @param isDefault * @param connectionType * @param associationDirection * @param highLighted * @param scaleFactor */
public void drawConnection(int[] xPoints, int[] yPoints, boolean conditional, boolean isDefault, String connectionType,
AssociationDirection associationDirection, boolean highLighted, double scaleFactor) { 

Paint originalPaint = g.getPaint();
Stroke originalStroke = g.getStroke();
g.setPaint(CONNECTION_COLOR);
if (connectionType.equals("association")) { 

g.setStroke(ASSOCIATION_STROKE);
} else if (highLighted) { 

//设置线的颜色
g.setPaint(HIGHLIGHT_SEQUENCEFLOW_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 == AssociationDirection.ONE || associationDirection == 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 == 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);
}
/** * 高亮节点设置 * @param x * @param y * @param width * @param height */
public void drawHighLight(int x, int y, int width, int height) { 

Paint originalPaint = g.getPaint();
Stroke originalStroke = g.getStroke();
//设置高亮节点的颜色
g.setPaint(HIGHLIGHT_COLOR);
g.setStroke(THICK_TASK_BORDER_STROKE);
RoundRectangle2D rect = new RoundRectangle2D.Double(x, y, width, height, 20, 20);
g.draw(rect);
g.setPaint(originalPaint);
g.setStroke(originalStroke);
}
/** * 条件表达式 value字体设置 * @param text * @param graphicInfo * @param centered */
public void drawLabel(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();
g.setPaint(LABEL_COLOR);
g.setFont(LABEL_FONT);
int wrapWidth = 100;
double textY = 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, (float) textY);
textY += tl.getDescent() + tl.getLeading() + (interline - 1.0f) * tl.getAscent();
}
// restore originals
g.setFont(originalFont);
g.setPaint(originalPaint);
}
}
}

4.2 扩展DefaultProcessDiagramGenerator

package top.theonly.workflow.image;
import org.flowable.bpmn.model.*;
import org.flowable.image.impl.DefaultProcessDiagramGenerator;
import java.util.*;
public class MyDefaultProcessDiagramGenerator extends DefaultProcessDiagramGenerator { 

protected MyDefaultProcessDiagramCanvas generateProcessDiagram(BpmnModel bpmnModel, String imageType,
List<String> highLightedActivities, List<String> highLightedFlows,
String activityFontName, String labelFontName, String annotationFontName, ClassLoader customClassLoader, double scaleFactor, boolean drawSequenceFlowNameWithNoLabelDI) { 

this.prepareBpmnModel(bpmnModel);
MyDefaultProcessDiagramCanvas processDiagramCanvas = initProcessDiagramCanvas(bpmnModel, imageType,
activityFontName, labelFontName, annotationFontName, customClassLoader);
// 实现同父类实现一模一样
// 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, scaleFactor);
}
// Draw lanes
for (org.flowable.bpmn.model.Process process : bpmnModel.getProcesses()) { 

for (Lane lane : process.getLanes()) { 

GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(lane.getId());
processDiagramCanvas.drawPoolOrLane(lane.getName(), graphicInfo, scaleFactor);
}
}
// Draw activities and their sequence-flows
for (org.flowable.bpmn.model.Process process : bpmnModel.getProcesses()) { 

for (FlowNode flowNode : process.findFlowElementsOfType(FlowNode.class)) { 

if (!isPartOfCollapsedSubProcess(flowNode, bpmnModel)) { 

drawActivity(processDiagramCanvas, bpmnModel, flowNode, highLightedActivities, highLightedFlows, scaleFactor,drawSequenceFlowNameWithNoLabelDI);
}
}
}
// Draw artifacts
for (org.flowable.bpmn.model.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) { 

GraphicInfo graphicInfo = bpmnModel.getGraphicInfo(subProcess.getId());
if (graphicInfo != null && graphicInfo.getExpanded() != null && !graphicInfo.getExpanded()) { 

continue;
}
if (!isPartOfCollapsedSubProcess(subProcess, bpmnModel)) { 

for (Artifact subProcessArtifact : subProcess.getArtifacts()) { 

drawArtifact(processDiagramCanvas, bpmnModel, subProcessArtifact);
}
}
}
}
}
return processDiagramCanvas;
}
protected static MyDefaultProcessDiagramCanvas initProcessDiagramCanvas(BpmnModel bpmnModel, String imageType,
String activityFontName, String labelFontName, String annotationFontName, ClassLoader customClassLoader) { 

// 这里与父类代码一模一样
// 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 (org.flowable.bpmn.model.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;
}
//设置返回自定义ProcessDiagramCanvas
return new MyDefaultProcessDiagramCanvas((int)maxX + 10, (int)maxY + 10, (int)minX, (int)minY, imageType, activityFontName, labelFontName, annotationFontName, customClassLoader);
}
}

4.3 或者自定义类实现ProcessDiagramGenerator

将DefaultProcessDiagramGenerator的代码拷过来
将类中的 DefaultProcessDiagramCanvas 改成 MyDefaultProcessDiagramCanvas 即可
不要忘了修改构造函数

4.4 使用自定义的流程图生成器生成流程图

将 3 代码中的默认生成器替换为自定义的生成器即可

//DefaultProcessDiagramGenerator defaultProcessDiagramGenerator = new DefaultProcessDiagramGenerator();
MyDefaultProcessDiagramGenerator defaultProcessDiagramGenerator = new MyDefaultProcessDiagramGenerator();