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creating a Rectangle

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Andre Hora

creating a Rectangle

Hello,

To create a Rectangle in Pharo with the method Rectangle>>origin:corner:, you must provide the top left and the bottom right points. With others you have a Rectangle with area equals to zero.
I just noticed that in VW it is possible create a Rectangle with other points (bottom right and top left, bottom left and top right, ...).
So, shouldn't Pharo Rectangle allow the same?

regards,

--
Andre Hora

Stéphane Ducasse

Re: creating a Rectangle

Give us the code!
In VW and Pharo side by side and their results

Stef

On Apr 6, 2011, at 10:31 AM, Andre Hora wrote:

> Hello,
>
> To create a Rectangle in Pharo with the method Rectangle>>origin:corner:, you must provide the top left and the bottom right points. With others you have a Rectangle with area equals to zero.
> I just noticed that in VW it is possible create a Rectangle with other points (bottom right and top left, bottom left and top right, ...).
> So, shouldn't Pharo Rectangle allow the same?
>
> regards,
>
> --
> Andre Hora
>

Andre Hora

Re: creating a Rectangle

Hello,

VW:
(Rectangle origin: (0@0) corner: (10@10)) area. 100
(Rectangle origin: (0@10) corner: (10@0)) area. -100
(Rectangle origin: (10@10) corner: (0@0)) area. 100
(Rectangle origin: (10@0) corner: (0@10)) area. -100

Pharo:
(Rectangle origin: (0@0) corner: (10@10)) area. 100
(Rectangle origin: (0@10) corner: (10@0)) area. 0
(Rectangle origin: (10@10) corner: (0@0)) area. 0
(Rectangle origin: (10@0) corner: (0@10)) area. 0

On Wed, Apr 6, 2011 at 1:05 PM, Stéphane Ducasse <[hidden email]> wrote:

Give us the code!
In VW and Pharo side by side and their results

Stef

On Apr 6, 2011, at 10:31 AM, Andre Hora wrote:

> Hello,
>
> To create a Rectangle in Pharo with the method Rectangle>>origin:corner:, you must provide the top left and the bottom right points. With others you have a Rectangle with area equals to zero.
> I just noticed that in VW it is possible create a Rectangle with other points (bottom right and top left, bottom left and top right, ...).
> So, shouldn't Pharo Rectangle allow the same?
>
> regards,
>
> --
> Andre Hora
>

--
Andre Hora

Igor Stasenko

Re: creating a Rectangle

area
"Answer the receiver's area, the product of width and height."
| w |
(w := self width) <= 0 ifTrue: [ ^ 0 ].
^ w * self height max: 0

what i found that rectangles don't like if corner point having
coordinates (either x or y)
which is below the origin.

many places in code (and especially in morphic) assuming that for any rectangle:
rect origin >= rect corner.

On 6 April 2011 13:51, Andre Hora <[hidden email]> wrote:

> Hello,
>
> VW:
> (Rectangle origin: (0@0) corner: (10@10)) area. 100
> (Rectangle origin: (0@10) corner: (10@0)) area. -100
> (Rectangle origin: (10@10) corner: (0@0)) area. 100
> (Rectangle origin: (10@0) corner: (0@10)) area. -100
>
> Pharo:
> (Rectangle origin: (0@0) corner: (10@10)) area. 100
> (Rectangle origin: (0@10) corner: (10@0)) area. 0
> (Rectangle origin: (10@10) corner: (0@0)) area. 0
> (Rectangle origin: (10@0) corner: (0@10)) area. 0
>
> On Wed, Apr 6, 2011 at 1:05 PM, Stéphane Ducasse <[hidden email]>
> wrote:
>>
>> Give us the code!
>> In VW and Pharo side by side and their results
>>
>> Stef
>>
>> On Apr 6, 2011, at 10:31 AM, Andre Hora wrote:
>>
>> > Hello,
>> >
>> > To create a Rectangle in Pharo with the method
>> > Rectangle>>origin:corner:, you must provide the top left and the bottom
>> > right points. With others you have a Rectangle with area equals to zero.
>> > I just noticed that in VW it is possible create a Rectangle with other
>> > points (bottom right and top left, bottom left and top right, ...).
>> > So, shouldn't Pharo Rectangle allow the same?
>> >
>> > regards,
>> >
>> > --
>> > Andre Hora
>> >
>>
>>
>
>
>
> --
> Andre Hora
>
>

--
Best regards,
Igor Stasenko AKA sig.

Stéphane Ducasse

Re: creating a Rectangle

In reply to this post by Andre Hora

Thanks andre
Igor I'm sure that we can understand the implementation of area.
I asked andre to post it because I was concerned that this difference of behavior is a bit odd.
And I wanted to raise awareness and may be that we question ourselves.
Now I do not have that much preconceived point of view on it.

Stef

> Hello,
>
> VW:
> (Rectangle origin: (0@0) corner: (10@10)) area. 100
> (Rectangle origin: (0@10) corner: (10@0)) area. -100
> (Rectangle origin: (10@10) corner: (0@0)) area. 100
> (Rectangle origin: (10@0) corner: (0@10)) area. -100
>
> Pharo:
> (Rectangle origin: (0@0) corner: (10@10)) area. 100
> (Rectangle origin: (0@10) corner: (10@0)) area. 0
> (Rectangle origin: (10@10) corner: (0@0)) area. 0
> (Rectangle origin: (10@0) corner: (0@10)) area. 0
>
> On Wed, Apr 6, 2011 at 1:05 PM, Stéphane Ducasse <[hidden email]> wrote:
> Give us the code!
> In VW and Pharo side by side and their results
>
> Stef
>
> On Apr 6, 2011, at 10:31 AM, Andre Hora wrote:
>
> > Hello,
> >
> > To create a Rectangle in Pharo with the method Rectangle>>origin:corner:, you must provide the top left and the bottom right points. With others you have a Rectangle with area equals to zero.
> > I just noticed that in VW it is possible create a Rectangle with other points (bottom right and top left, bottom left and top right, ...).
> > So, shouldn't Pharo Rectangle allow the same?
> >
> > regards,
> >
> > --
> > Andre Hora
> >
>
>
>
>
>
> --
> Andre Hora
>

Igor Stasenko

Re: creating a Rectangle

On 6 April 2011 22:15, Stéphane Ducasse <[hidden email]> wrote:
> Thanks andre
> Igor I'm sure that we can understand the implementation of area.
> I asked andre to post it because I was concerned that this difference of behavior is a bit odd.
> And I wanted to raise awareness and may be that we question ourselves.
> Now I do not have that much preconceived point of view on it.
>

Me neither.
I found it odd that some pieces of code relying that origin <= corner
(sorry i mistaken in previous mail)

i meant that

origin x <= corner x
origin y <= corner y

and yes, there is some code that assumes it is always like that.

So, yes. While in pure geometry two different corner points could
define a rectangle, no matter
in what order you put them, in pharo/squeak geometry it sometimes matters :)

But of course you can try and figure out what is works and what not,
and fix it :)

> Stef
>

--
Best regards,
Igor Stasenko AKA sig.

Henrik Sperre Johansen

Re: creating a Rectangle

http://forum.world.st/vwnc-Rectangle-td1414824.html
http://forum.world.st/Behavior-of-Rectangle-td2021104.html#a2021123

Personally, I like vertex:vertex: :)

drush66

Re: creating a Rectangle

In reply to this post by Igor Stasenko

On Wed, Apr 6, 2011 at 11:09 PM, Igor Stasenko <[hidden email]> wrote:

> Me neither.
> I found it odd that some pieces of code relying that origin <= corner
> (sorry i mistaken in previous mail)
>
> i meant that
>
> origin x <= corner x
> origin y <= corner y
>
> and yes, there is some code that assumes it is always like that.
>
> So, yes. While in pure geometry two different corner points could
> define a rectangle, no matter
> in what order you put them, in pharo/squeak geometry it sometimes matters :)
>
> But of course you can try and figure out what is works and what not,
> and fix it :)

hmm.. I am not sure if this would improve situation or make situation
even more ugly, but maybe #origin:corner: could figure out how to
create rectangle from given parameters that satisfies:

new_origin x <= new_corner x
new_origin y <= new_corner y

in other words, resulting rectangle may have different origin and
corner than one supplied to #origin:corner:

Davorin Rusevljan
http://www.cloud208.com/

http://www.cloud208.com/