rubber.md
In rswipl: Embed 'SWI'-'Prolog'

class rubber {#class-rubber}

A rubber object is associated to hbox <-rubber to declare the stretchability of the box as well as its possibility to break lines. See class parbox for an overview of the document rendering primitives.

Attributes:

<-level After collecting the hbox objects for a line, all boxes that share the highest <-level are used to distribute the remaining horizontal space on the line. Values used are:
```
1   spaces
2   alignment
3   stretching lines, etc.
```
<-shrink Difficulty to get smaller. 0 implies the box does not want to get smaller (default). Higher values represent more ease to get smaller.
<-stretch Difficulty to get wider. 0 impliesthe box does not want to get wider (default). Higher values represent more ease to get wider.

<-linebreak Possibility to break a line

| @nil  | Cannot start a new line |
| allow | May start a new line    |
| force | Must start a new line   |

<-natural Defined natural size. If @default, the size is determined from the content.
<-minimum Minimum size. Try as hard as possible to avoid getting smaller.
<-maximum Maximum size. Try as hard as possible to avoid getting larger.

See also @space_rubber.

rubber->initialise: level=[1..], stretch=[0..], shrink=[0..], linebreak=[{allow,force}]* Create a rubber object initialising ->level, ->stretch, ->shrink and ->linebreak. Other useful properties are:
```
| ->maximum: | Maximum size of object   |
| ->minimum: | Minimum size of object   |
| ->natural: | Preferred size of object |
```