[openbeos] Re: Printing the Tracker - Rectangle Printing

"Alexander G. M. Smith" <agmsmith@xxxxxxxxxx> wrote:

> Macintosh Quickdraw and Windows use rectangles where Width = right - left.  
> BeOS width doesn't count pixels, it's off by one.
Their coordinates are the grid between the pixels, so a rectangle with diagonal 
corners (0,0) and (1,1) is a rectangle around a
single pixel.  BeOS has the grid down the middle of pixels so it's harder to 
tell what's going to happen when drawing.  If you want
rectangles to butt up against each other without a gap, in Mac & Windows you 
just make the next rectangle's left X coordinate equal
to the previous rectangle's right X coordinate.
>
> Lots of BeOS software has off by one errors due to the confusing coordinate 
> system - like NetPositive's image display (misses one
pixel at the edge).

yes, Alex
still that does not make the coordinate system 'inappropriate for use with 
bitmaps' ;)
actually for such purposes it's virtually the same as qdraw's or gdi's - one 
just has to be
aware of the semantics of the systm. point being if you were of beos background
you'd be holding the opposite opinion now ;)

-blu

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