RE: Balanced lines

The type of line break behavior you refer to below is considered to be an advanced typesetting feature only available in fairly high-end pre-press systems (it is known in typesetting as "river control"). I can't imagine that any subtitle/cc user agent would implement it.
 
See http://www.coathook.pwp.blueyonder.co.uk/comp/comp3a.htm for some discussion of river control.
 
Also, clearly a UA is not going to perform sentential analysis to determine line break points.
 
G.

	-----Original Message-----
	From: Johnb@screen.subtitling.com [mailto:Johnb@screen.subtitling.com] 
	Sent: Wednesday, August 13, 2003 11:02 AM
	To: Glenn A. Adams
	Cc: public-tt@w3.org
	Subject: Balanced lines
	
	
	Glenn 

		[JB> ] CSS wrap-option property does not have a value that produces balanced lines. Justification properties do not appear to help either. 
		
		GA: What do you mean by "balanced lines"? If you mean left and right block justified, then the text-align property would be used to specify justify. Whether to perform soft layout, i.e., UA line wrapping, is independent of the alignment of line areas in the containing block area.
		
		[JB> ]  No I don't mean block justified. It's an issue of where in the lines to put a line break. 
		 
		So given a content of "Scooby dooby doo where are you?" a typical line break mechanism might break this as follows for a 22 character 2 line display (for ease lets assume a fixed font - as in Teletext).
		

		
		Scooby dooby doo where 
		are you?
		
		The more balanced lines would be
		 
		Scooby dooby doo 
		where are you?
		
		From Australian Caption Centre guidelines
		 
		" Where possible, caption lines should also be similar in length because this makes them much easier to read." 

		 

		YMMV

		 

		There are a number of other 'rules' regarding line breaking that may or may not be desirable. However most of these require a detailed understanding of grammar....which I think is probably straying well outside the remit....

		 

		regards 
		John Birch 

		The views and opinions expressed are the author's own and do not necessarily 
		reflect the views and opinions of Screen Subtitling Systems Limited.