======Common commands======
======Footer and header======
You can use the commands header or footer to add a footer or a header on any generated diagram.

You can optionally specify if you want a center, left or right footer/header, by adding a keyword.
As for title, it is possible to define a header or a footer on several lines.
It is also possible to put some HTML into the header or footer.

<uml t="commons">
Alice -> Bob: Authentication Request

header
<font color=red>Warning:</font>
Do not use in production.
endheader

center footer Generated for demonstration
</uml>

======Zoom======
You can use the scale command to zoom the generated image.
You can use either a number or a fraction to define the scale factor. You can
also specify either width or height (in pixel). And you can also give both
width and height : the image is scaled to fit inside the specified dimension.
    * scale 1.5
    * scale 2/3
    * scale 200 width
    * scale 200 height
    * scale 200*100
<uml t="commons_001">
scale 180*90
Bob->Alice : hello
</uml>