# Difference between revisions of "Collectors"

Collectors are an alternative to overlays that can be used to build-up composite objects. Layers on the other hand, are used to define whole pages. See the details manual for further explanations.

## Example

```\starttext

\definecollector[example]
\setcollector [example] { \externalfigure[cow][width=4cm,frame=on] }
\setcollector [example] [corner={right,bottom},location={left,top}]
{\framed{1}}
\setcollector [example] [corner={right,top},location={left,bottom}]
{\framed{2}}
\setcollector [example] [corner={left,top},location={right,bottom}]
{\framed{3}}
\setcollector [example] [corner={left,bottom},location={right,top}]
{\framed{4}}

\startTEXpage
\composedcollector{example}
\stopTEXpage

\stoptext
```

There is no confusion if the added text is placed within the first object. However,

```\starttext

\definecollector[example2]
\setcollector [example2] { \externalfigure[cow][width=4cm,frame=on] }
\setcollector [example2] [corner={right,bottom},location={right,bottom}]
{\framed{1}}
\setcollector [example2] [corner={right,top},location={right,top}]
{\framed{2}}
\setcollector [example2] [corner={left,top},location={left,top}]
{\framed{3}}
\setcollector [example2] [corner={left,bottom},location={left,bottom}]
{\framed{4}}

\startTEXpage
\composedcollector{example2}
\stopTEXpage

\stoptext
```

Notice that the size of the collected object grows as text is added. As a consequence, the positions of the corners get redefined as the bounding box grows.