From: James Edward Gray II <james@...>
Date: 2004-12-10T00:47:09+09:00
Subject: Re: [SUMMARY] Crosswords (#10)

On Dec 9, 2004, at 8:55 AM, Brian Schr�der wrote:

> Hello James,
>
> Nice summary, thanks you again. Did you benchmark the solutions, I 
> would be
> interested in how fast/slow some approaches where. Especially those 
> that rely
> heavily on string manipulation, vs. those that build up the layout in a
> streaming fashion.

I didn't benchmark this time no.  Everything I ran was "faster than I 
blink" zippy.  ;)

>> (Note:  This "collapsing borders" technique is common in many aspects 
>> of
>> programming.  Examine the output of the mysql command line tool, GNU 
>> Chess,
>> or a hundred other tools.  It's also common for GUI libraries to 
>> combine
>> borders of neighboring elements.)
>>
>
> One remark here, is that it is common for filling algorithms not to 
> draw each
> border twice, but to draw only borders on two sides of the elements. 
> Especially
> if you have a line drawing algorithm (e.g. Bresenham) and you draw 
> adjacent
> lines of polygons twice, it is 1. a waste of energy and 2. rounding 
> errors may
> lead to jitter, such that the lines do not overlap perfectly.
>
> (On a second read I'm not that shure that I understood you perfectly, 
> so if I
> was ranting about something you already said, I'm sorry for the noise.)

I should have written that note more clearly.  I wasn't trying to say 
that drawing the borders twice was the technique to always use (though 
it works fine in many cases).  I was trying to say that the need to 
collapse borders like that comes up a lot, however you accomplish it.  
My bad.

James Edward Gray II