Plantuml Usage Summary

I have used this tool before , I saw 2 Very good plantuml teaching , But I didn't summarize , So after a while, I forgot . I've been doing nothing for a long time , So let's write a summary ;
Of course , First, install the plug-in , stay idea Very convenient , Directly in plugins On the search plantuml That's all right. ;
plantuml There are many uses （ I reprinted an article about plantuml A tutorial for Connection address , There are many fancy usages , Those who are interested can study ）, This article is just an introduction , If it is only used to draw flow charts , It's enough for work ;

uml Structure

@startuml   
xxxxx
xxxx
xxx

@enduml

As shown in the figure above ,uml All the grammar , All wrapped in @startuml @enduml Between ; Next , Let's take a look at uml The grammar of

Basic grammar 1 :XXXX;

Don't talk much , Look at the renderings ：
The main structure of the flow chart is probably such a thing ; So this is the most basic and important grammatical structure ;
Speaking of which, I would also like to introduce 2 individual , Compare basic keywords start ,end; this 2 Words mean the process Start and end , this 2 Words can be used separately ;
Look at the usage and effect pictures ：

In fact this 2 Key words , It can make the flow chart look clearer , Because when the flow chart is very complex and there are many branches , Use end, It allows people to see more intuitively where a specific branch ends

Basic grammar 2 ：if structure

Because a lot of times , We draw a flow chart , It will inevitably involve the situation of branches , therefore if Structure is also very common ; Learning this should actually feel familiar , Because the structure of programming language is too similar , After reading it, you can write it immediately ;

2.1 Simple if structure

@startuml
if(conditon1)then(yes)
: Satisfy conditon1, Take the branch 1;
else
:no, Take a branch 2;
endif
@enduml

design sketch ：

2.2 multiple if structure

usage ： When there are many branches , Different conditions must be met before entering the corresponding branch , This time , You should use multiple if structure
grammar ：

if(condition1)then(yes)
   : event 1;
   : event 2;
   : event 3;
   end
elseif(condition2)then(yes)
: event 1;
elseif(condition3)then(yes)
: event 1;
elseif(condition4)then(yes)
: event 1;
endif

design sketch ：

Here you can see , I added end, Keyword indicates that the process enters condition1 in , The whole process is over , Very intuitive ; So use when appropriate end keyword , It will make the flow chart more suitable for people to view ;

2.3 if Nesting of structures

above 2 The first grammatical structure is uml Of if Basic usage of structure ; occasionally , Maybe we will encounter a situation , Is in a branch , There are other branches , At this time, it can be nested in a branch if structure ;
Pictured ：

Basic grammar 3 ： Loop structure while

start

while(conditon)is(not empty)
:read file;
endwhile(empty)
:close file --> End of the process ;
stop

When use , No keywords ：start,stop, You can also use , However, it is recommended to add , Use a complete structure , Don't talk much , Look at the renderings ：

One more word here , stay while In circulation It can also be added if Structural , Actually in uml In the grammar of , Any structure can be nested in any structure , Can be in if In structure , set while, And vice versa ,（ There are other structures behind , In fact, they can be nested with each other ） This nesting is widely used , You can find it by yourself ;
Draw one here ：

In this way, various nested combinations can cope with most workflow diagrams ;

Basic grammar 4 ： Parallel structure fork

Use this structure , You can simplify some flow charts , When there is no sequence of events , This structure can be used ; Let's talk about grammar first , And the renderings

fork
:;
fork again
:;
fork again
:;
end fork

there fork again You can add as many as you like , This sum if The structure is very similar

Use scenario suggestions ： When the flow chart is long , Consider classifying processes
such as ：
ad locum ： Thing 1, Thing 2, Thing 3 Between , There is no order of precedence （ There's no connection ）, If you draw the flow chart in such a straightforward way , It's not intuitive , It also seems difficult ; If you use fork The structure is different ;

In the use of fork After structure , The whole process is much clearer than before ;
Many say , there fork structure , Can also be combined with if,while nesting ;

Basic grammar five ： notes

When drawing the flow chart , In order to make it easier for people to understand, sometimes , Some notes will be marked to explain some terms or processes , Or important data, etc ...
So annotation is also very important
grammar ：

 grammar 1：
floating note left:  Left note 

 grammar 2：
note right
	 Note on the right 
end note

design sketch ：


Let's emphasize here , To annotate a line , Write the comment structure just below this line ;

5.1 Other syntax for comments

In the comments
note right
XXXX
end note
Can be used in the structure of

• html grammar
• ====（ You can split rows ）
• "*" Represents a list
  Pictured ：
  

Grammar 6 ： Color syntax

This grammar is also very interesting , Is to mark a line with a color ;
grammar ：

# english （ Or hexadecimal ）:XXXXX;

Here is a color conversion website , Please refer to this website for the colors you need Color website links
design sketch ：

The English words here , And hexadecimal codes are recommended Color website links You can try to check on ;

That's all uml Basic grammar , There are other grammars , But it doesn't seem to be very useful , So I won't summarize ; If you want to see other grammars , You can see the connection uml Tutorial recommendation