Re: Checking: difference between negative stretch and positive shrink?

2007-09-17 Thread Andreas L Delmelle

On Sep 17, 2007, at 14:17, Luca Furini wrote:


Andreas L Delmelle wrote:

Just wondering about some KnuthSequences for spaces I noticed  
during a debug-session:




Negative stretch is not the same as a positive shrink (and vice- 
versa): a negative stretch is used to cancel (or diminish) a  
positive one provided by some other elements: for each possible  
break point, however, the overall stretch / shrink should always be  
>= 0.


The meaning of the mini-sequence above is:
- if there is a break at the penalty element, there is some stretch  
for

  the line ending there
- otherwise, the overall stretch is zero

This is with unjustified text to give each line the same amount of  
stretch, so that the algorithm should build lines with similar  
length (while in justified text a line with many spaces and few  
letters could be stretched a lot).


HTH


It did. Thanks for the quick explanation.

Cheers

Andreas



Re: Checking: difference between negative stretch and positive shrink?

2007-09-17 Thread Luca Furini

Andreas L Delmelle wrote:

Just wondering about some KnuthSequences for spaces I noticed during 
a debug-session:


glue w=0 stretch=10008 shrink=0
penalty w=0 p=0
glue w=3336 stretch=-10008 shrink=0

What does it mean that the latter glue can be stretched by a negative 
amount?

Why not:
glue w=3336 stretch=0 shrink=10008

Is there a difference as to how the algorithm treats these?


Negative stretch is not the same as a positive shrink (and vice-versa): a 
negative stretch is used to cancel (or diminish) a positive one provided 
by some other elements: for each possible break point, however, the 
overall stretch / shrink should always be >= 0.


The meaning of the mini-sequence above is:
- if there is a break at the penalty element, there is some stretch for
  the line ending there
- otherwise, the overall stretch is zero

This is with unjustified text to give each line the same amount of 
stretch, so that the algorithm should build lines with similar length 
(while in justified text a line with many spaces and few letters could be 
stretched a lot).


HTH

Luca