Am 05.11.2005 um 18:37 schrieb stéphane ducasse:

> testContainsPoint
>     "self run: #testContainsPoint"
>
>     self assert: ((0 at 0 extent: 300 at 200) containsPoint: 100 at 100).
>     self deny: ((0 at 0 extent: 300 at 200) containsPoint: 0 at 299).
>     self assert: ((0 at 0 extent: 300 at 200) containsPoint: 0 at 199).
>
>
>     "strange behavior a rectangle includes a point that is equals to
>     its origin but not its corner"
>     self deny: ((0 at 0 extent: 300 at 200) containsPoint: 0 at 200).
>     self assert: ((0 at 0 extent: 300 at 200) containsPoint: 0 at 0).
>     self deny: ((0 at 0 extent: 300 at 200) containsPoint: 300 at 200).
>
> may be this is to make sure that a point cannot belongs to two  
> rectangles that would be just
> overlapping of one pixel?

Yes. Rasterizing two adjacent rectangles (e.g., "rect1 right = rect2  
left") should leave no gap and touch every pixel exactly once. This  
is a basic property of all graphics packages (google for  
"rasterization rules" if you want to learn more), but often comes as  
a surprise to graphics newbies, because geometry in school does not  
deal with rasterization.

- Bert -