src/swipl-devel/packages/xpce/man/refmanual/md/hbox.md

In rswipl: Embed 'SWI'-'Prolog'

class hbox {#class-hbox}

Class hbox denotes a horizontal box in the document rendering system, the basics of which are described with class parbox.

An hbox itself has no content and can only be used for layout. For this purpose they normally have a rubber object attached to them.

There are to subclasses of the hbox class. Class tbox represents text and class grbox represents an embedded graphical.

Attrinbutes:

• <-rubber Defines stretchability as well as possibility to break lines here.

• <-ascent Height above the baseline.

• <-descent Depth below the baseline

• <-width Horizontal width.

Instance variables {#class-hbox-instvars}

• hbox<-ascent: 0.. Height above baseline. For tbox objects this is the font<-ascent. For grbox objects this is determines by the grbox<-baseline attribute.

  Hbox objects with non-zero ascent are commonly used as first box in a paragraph to create vertical white space.

• hbox<-rubber: rubber* Stretch/shrinkability. See class rubber for details. The default <-rubber for an hbox object is @nil, implying the box' size is fixed and it can not break a line.

Send methods {#class-hbox-send}

• hbox->initialise: width=[int], ascent=[int], descent=[int], rubber=[rubber]* Create a hbox object from its attribute values. Plain hbox objects are only used for layout. See class tbox and class grbox for defining the content of parbox objects.

rswipl documentation built on June 16, 2026, 5:07 p.m.