Re: Release critical or not? [was Re: strange box-offset]

[Daniel J S. <dan...@ie...>]

Ethan A Merritt wrote:
> On Sunday 16 July 2006 12:05 pm, Daniel J Sebald wrote:
> 
>>>the fundamental question is whether "width" should be interpreted
>>>as "number of horizontal pixels" or "x_right - x_left".  These are not
>>>the same number.  The former makes sense if you are thinking in terms of
>>>terminal coords (pixels); the latter makes sense if you are thinking in 
>>>terms of a continuous variable (plot x coordinate).
>>
>>If you plot a series of rectangles to "cover" a range staying with 
>>x_right - x_left avoids there being an overlap of one pixel.   
> 
> 
> But then you have the discordance that if you simply draw the 
> rectangle bounded by (x1,y1) (x2,y2) with vectors, the bottom and
> left edges are part of the fill area, but the top and right edges
> are not.  Isn't that the problem being observed - that the fill
> area and the bounding lines do not agree?

Hmmm, yeah...

Well, maybe the bounding lines should also be drawn one less.  I'm getting this feeling of an analog with the bounding box issue of images.  We had that discussion (enlightening to me) a while back about how to deal with this sort of thing in images.  I recall the gist being that when one does computations translating the images, one should work with the bounding box values, not the location of the first and last pixel are... I think there was a one pixel difference.

Perhaps the same kind of thinking applies here.

Dan