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Does CSS-1 inhibit incremental rendering?

From: Gilbert Baumann <unk6@rz114s1.rz.uni-karlsruhe.de>
Date: Fri, 5 Jun 1998 14:59:58 +0200
To: www-style@w3.org
Message-Id: <E0yhw6A-0001S1-00@rz114s1.rz.uni-karlsruhe.de>
Hi folks, 
 
    Could somebody please enlighten me? 
 
    I am currently at implementing a CSS-1 based browser. It 
works pretty well so far. I am thinking about support for 
incremental rendering, to utilize idle time while the processor 
waits for data from the server. However after inspecting my code 
I recognized that CSS-1 pretty well inhibits incremental 
rendering. 
 
    The problem I see here is the 'width' attribute of 
block-level elements. Before I can go on and render the 
block-level elements contents, I have to compute the effective 
width 'ewidth'. 
 
(For sake of simplicity I formulate all below modulo the padding 
and border widthen). 
 
Assume the most common case, where 'width' is 'auto' and 
'margin-left' and 'margin-right' are absolute values. Then my 
interpretation of CSS-1, section 4.1.2 "Horizontal formatting" is 
to calculate the effective width 'ewidth' as follows: 
 
#  ewidth <- parent.width - margin-left - margin-right; 
 
Oops, this is t); 
 
Unfortunately the calculation of 'minimum-width' on block level 
elements requires the inspection of all children. The minimum 
width on block level elements is roughly: 
 
  x.minimum-width :=       Sup           c.minimum-width ; 
                       c in x.children  
 
This inhibits incremental rendering pretty well. 
 
So my questions are: 
 
 - What was the original intension of the above quoted rule. 
 - I am fundamentally wrong somewhere?  
 - Does CSS-1 really inhibit incremental rendering? 
   Tell this is not true -- I would be pretty much disappointed. 
 - Is my interpretation of 'non-negative UA-defined minimum 
   value' flawed? 
 
Through it is virtually late now, I hope I was able to 
communicate the point. 
 
Regards, 
    Gilbert 
 
 
PS. Please take my apologies if this is addressed in CSS-2. I am 
    tired of reading RFCs and following the newest and hotest 
    standards, so I settled on HTML-4.0 and CSS-1 to get my 
    project finished sometime. If standards get out faster than 
    you could code them, you'll never finish. 
Received on Friday, 5 June 1998 08:59:44 GMT

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