可以嵌入在markdown代码中的mermaid

mermaid的好处是可以在写markdown文档的同时，就直接可以画图了。
下面是我用Haroopad工具直接在markdown中画流图的情况：

工具下载地址：http://pad.haroopress.com/

独立使用mermaid

可以通过npm安装mermad：

npm install -g mermaid
npm install -g phantomjs

mermaid依赖于phantomjs

下面是mermaid的帮助信息：

Usage: mermaid [options] <file>...

file    The mermaid description file to be rendered

Options:
  -s --svg             Output SVG instead of PNG (experimental)
  -p --png             If SVG was selected, and you also want PNG, set this flag

  -o --outputDir       Directory to save files, will be created automatically, d
efaults to `cwd`
  -e --phantomPath     Specify the path to the phantomjs executable
  -t --css             Specify the path to a CSS file to be included when proces
sing output
  -c --sequenceConfig  Specify the path to the file with the configuration to be
 applied in the sequence diagram
  -g --ganttConfig     Specify the path to the file with the configuration to be
 applied in the gantt diagram
  -h --help            Show this message
  -v --verbose         Show logging
  -w --width           width of the generated png (number)
  --version            Print version and quit

mermaid数据流图速成

决定图的方向

与graphviz不同，graph语句首先需要设置图的方向

• TD: 默认方向，从上到下
• TB: 从上到下
• BT: 从下到上
• LR: 从左到右
• RL: 从右到左

例：

graph TB;
    Context_sendbroadcast --> ContextWrapper_sendBroadcast;
    ContextWrapper_sendBroadcast --> ContextImpl_sendBroadcast;
    ContextImpl_sendBroadcast --> ActivityManagerService_broadcastIntent;

与graphviz的不同

graphviz的dot图是用“节点1 -> 节点2”的格式，而mermaid是用“节点1 --> 节点2”的方式，中间多了一个"-".

属性定义方面，mermaid可以用[]和()几种方式来决定图形的方式。
比如：

graph TD;
    Context_sendbroadcast(Context.sendBroadcast Intent);
    ContextWrapper_sendBroadcast[ContextWrapper.sendBroadcast Intent];
    Context_sendbroadcast --> ContextWrapper_sendBroadcast;

Context_sendbroadcast就是圆脚的矩形，而ContextWrapper_sendBroadcast就是方的。

需要注意的一点，在标签属性定义的时候，不能出现()[]之类引起误会的符号。官方文档说可以用""来引起来，不过在我的版本上有点问题。

下面还是看跟上面一篇中所讲的graphviz完全一样的图的例子：

graph TD
    Context_sendbroadcast[Context.sendBroadcast Intent];
    Context_sendbroadcast_asUser[Context.sendBroadcastAsUser Intent,UserHandle];
    Context_sendOrderedBroadcast[Context.sendOrderedBroadcast Intent,String,BroadcastReceiver,Handler,int,String,Bundle];
    Context_sendOrderedBroadcast2[Context.sendOrderedBroadcast Intent,String];
    Context_sendStickyBroadcast[Context.sendStickyBroadcast Intent];
    Context_sendStickyBroadcast2[Context.sendStickyOrderedBroadcast Intent,BroadcastReceiver,Handler,int,String,Bundle];

    ContextWrapper_sendBroadcast[ContextWrapper.sendBroadcast Intent];

    ContextWrapper_sendOrderedBroadcast2[ContextWrapper.sendOrderedBroadcast Intent,String];
    ContextWrapper_sendOrderedBroadcast[ContextWrapper.sendOrderedBroadcast Intent,String,BroadcastReceiver,Handler,int,String,Bundle];
    ContextWrapper_sendStickyBroadcast[ContextWrapper.sendStickyBroadcast Intent];
    ContextWrapper_sendStickyBroadcast2[ContextWrapper.sendStickyOrderedBroadcast Intent,BroadcastReceiver,Handler,int,String,Bundle];
    ContextWrapper_sendbroadcast_asUser[ContextWrapper.sendBroadcastAsUser Intent,UserHandle];
    ContextImpl_sendBroadcast[ContextImpl.sendBroadcast Intent];
    ContextImpl_sendOrderedBroadcast2[ContextImpl.sendOrderedBroadcast Intent,String];
    ContextImpl_sendOrderedBroadcast[ContextImpl.sendOrderedBroadcast Intent,String,BroadcastReceiver,Handler,int,String,Bundle];
    ContextImpl_sendStickyBroadcast[ContextImpl.sendStickyBroadcast Intent];
    ContextImpl_sendStickyBroadcast2[ContextImpl.sendStickyOrderedBroadcast Intent,BroadcastReceiver,Handler,int,String,Bundle];
    ContextImpl_sendbroadcast_asUser[ContextImpl.sendBroadcastAsUser Intent,UserHandle];
    ContextImpl_sendOrderedBroadcast_all(ContextImpl.sendOrderedBroadcast Intent,String,int,BroadcastReceiver,Handler,int,String,Bundle,Bundle);

    ActivityManagerService_broadcastIntent(ActivityManagerService.broadcastIntent IApplicationThread,Intent,String,IIntentReceiver,int,String,Bundle,String,int,Bundle,boolean,boolean,int);

    Context_sendbroadcast --> ContextWrapper_sendBroadcast;
    ContextWrapper_sendBroadcast --> ContextImpl_sendBroadcast;
    ContextImpl_sendBroadcast --> ActivityManagerService_broadcastIntent;

    Context_sendbroadcast_asUser --> ContextWrapper_sendbroadcast_asUser;
    ContextWrapper_sendbroadcast_asUser --> ContextImpl_sendbroadcast_asUser;
    ContextImpl_sendbroadcast_asUser --> ActivityManagerService_broadcastIntent;

    Context_sendOrderedBroadcast2 --> ContextWrapper_sendOrderedBroadcast2;
    ContextWrapper_sendOrderedBroadcast2 --> ContextImpl_sendOrderedBroadcast2;
    ContextImpl_sendOrderedBroadcast2 --> ActivityManagerService_broadcastIntent;

    Context_sendOrderedBroadcast --> ContextWrapper_sendOrderedBroadcast;
    ContextWrapper_sendOrderedBroadcast --> ContextImpl_sendOrderedBroadcast;
    ContextImpl_sendOrderedBroadcast --> ContextImpl_sendOrderedBroadcast_all;
    ContextImpl_sendOrderedBroadcast_all --> ActivityManagerService_broadcastIntent;

    Context_sendStickyBroadcast --> ContextWrapper_sendStickyBroadcast;
    ContextWrapper_sendStickyBroadcast --> ContextImpl_sendStickyBroadcast;
    ContextImpl_sendStickyBroadcast --> ActivityManagerService_broadcastIntent;

    Context_sendStickyBroadcast2 --> ContextWrapper_sendStickyBroadcast2;
    ContextWrapper_sendStickyBroadcast2 --> ContextImpl_sendStickyBroadcast2;
    ContextImpl_sendStickyBroadcast2 --> ActivityManagerService_broadcastIntent;

下面是生成的图片：