YUML支持3种图示风格，分别是：

1. plain
2. scruffy
3. boring

用例图

1. 角色(Actor)
2. 使用[角色名]

![](http://yuml.me/diagram/plain/usecase/[Customer])

![](http://yuml.me/diagram/scruffy/usecase/[Customer])

![](http://yuml.me/diagram/boring/usecase/[Customer])

用例(Use Case)
使用(用例名)表示用例，-表示角色和用例之间的关联。

![](http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login),[Customer]-(Logout))

1. 备注(Notes)
2. 如果用例名以note:开头,表明那是一个备注,可以用{bg:颜色名}定义备注的背景色

![](http://yuml.me/diagram/plain/usecase/[Customer]-(Login), 
[Customer]-(note:Cust can be registered or not{bg:beige}))

,
[Customer]-(note:Cust can be registered or not{bg:beige}))

![](http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login),
[Customer]-(note:Cust can be registered or not{bg:beige}))

,
[Customer]-(note:Cust can be registered or not{bg:beige}))

角色继承(Actor Inheritance)
使用符号^表示角色之间的继承关系

![](http://yuml.me/diagram/scruffy/usecase/[Cms Admin]^[User], [Customer]^[User],[Agent]^[User])


扩展和包含(Extends and Includes)
使用>表示用例之间的包含关系，<表示用例之间的扩展

![](http://upload-images.jianshu.io/upload_images/46259-dc05b84aa2bc8bed?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)<(Register),(Login)<(Request Password Reminder),(Register)>(Confirm Registration))

<(Register),(Login)<(Request Password Reminder),(Register)>(Confirm Registration))

完整示例

plain

![](http://yuml.me/diagram/plain/usecase/(note: figure  1.2{bg:beige}), [User]-(Login),[Site Maintainer]-(Add User),(Add User)<(Add Company),[Site Maintainer]-(Upload Docs),(Upload Docs)<(Manage Folders),[User]-(Upload Docs),[User]-(Full Text Search Docs), (Full Text Search Docs)>(Preview Doc),(Full Text Search Docs)>(Download Docs),[User]-(Browse Docs), (Browse Docs)>(Preview Doc),[Site Maintainer]-(Post New Event To The Web Site),[User]-(View Events))

, [User]-(Login),[Site Maintainer]-(Add User),(Add User)<(Add Company),[Site Maintainer]-(Upload Docs),(Upload Docs)<(Manage Folders),[User]-(Upload Docs),[User]-(Full Text Search Docs), (Full Text Search Docs)>(Preview Doc),(Full Text Search Docs)>(Download Docs),[User]-(Browse Docs), (Browse Docs)>(Preview Doc),[Site Maintainer]-(Post New Event To The Web Site),[User]-(View Events))

scruffy

, [User]-(Login),[Site Maintainer]-(Add User),(Add User)<(Add Company),[Site Maintainer]-(Upload Docs),(Upload Docs)<(Manage Folders),[User]-(Upload Docs),[User]-(Full Text Search Docs), (Full Text Search Docs)>(Preview Doc),(Full Text Search Docs)>(Download Docs),[User]-(Browse Docs), (Browse Docs)>(Preview Doc),[Site Maintainer]-(Post New Event To The Web Site),[User]-(View Events))

boring

, [User]-(Login),[Site Maintainer]-(Add User),(Add User)<(Add Company),[Site Maintainer]-(Upload Docs),(Upload Docs)<(Manage Folders),[User]-(Upload Docs),[User]-(Full Text Search Docs), (Full Text Search Docs)>(Preview Doc),(Full Text Search Docs)>(Download Docs),[User]-(Browse Docs), (Browse Docs)>(Preview Doc),[Site Maintainer]-(Post New Event To The Web Site),[User]-(View Events))

nofunky

, [User]-(Login),[Site Maintainer]-(Add User),(Add User)<(Add Company),[Site Maintainer]-(Upload Docs),(Upload Docs)<(Manage Folders),[User]-(Upload Docs),[User]-(Full Text Search Docs), (Full Text Search Docs)>(Preview Doc),(Full Text Search Docs)>(Download Docs),[User]-(Browse Docs), (Browse Docs)>(Preview Doc),[Site Maintainer]-(Post New Event To The Web Site),[User]-(View Events))