nested block-container approach

[Giuseppe Briotti <g....@gmail.com>]

The problem:

I have a page with a body divided in 3 areas (say top, middle and bottom).
The total height of the 3 areas is fixed. The content of the 3 areas may
varies, thus the height of each area must be adaptable but around 33% of the
total height.

The proposed solution:

As a solution, I'm thinking about some nested block containers with
appropriate set of block-progression-dimension. In pseudo code:

<!-- first external block of whole area
<fo:block-container  block-progression-dimension.minimum="21cm"
block-progression-dimension.optimum="21cm"
block-progression-dimension.maximum="21cm" >

     <!-- top area -->
     <fo:block-container  block-progression-dimension.minimum="5cm"
block-progression-dimension.optimum="7cm"
block-progression-dimension.maximum="9cm" >
           ........content.........
     </fo:block-container>

     <!-- middle area -->
     <fo:block-container  block-progression-dimension.minimum="5cm"
block-progression-dimension.optimum="7cm"
block-progression-dimension.maximum="9cm" >
           ........content.........
     </fo:block-container>

     <!-- bottom area -->
     <fo:block-container  block-progression-dimension.minimum="5cm"
block-progression-dimension.optimum="7cm"
block-progression-dimension.maximum="9cm" >
           ........content.........
     </fo:block-container>

</fo:block-container>

Question(s):

Is this approach correct?
I'm missing something?
Someone here did something like this?
Can the external constraint (i.e. total height = 21cm) affects the internal
constraints in order to set each internal height properly?

TIA


-- 

Giuseppe Briotti
g.briotti@gmail.com

"Alme Sol, curru nitido diem qui
promis et celas aliusque et idem
nasceris, possis nihil urbe Roma
visere maius."
(Orazio)