It looks like Connectors does not map curves directly to balloon  
since the two arrays that you provided does not build the same shape.  
The first one draws a square, while the second one draws a kind of  
triangle (see below).

Noury

Le 8 sept. 06 à 01:22, Andreas Raab a écrit :

> I have no idea how connectors handle this. If it's mapped straight  
> into Balloon then it should be the case that you can make up  
> arbitrary segments but that they should form closed shapes for  
> rendering. E.g., instead of a "regular" set of curves like here:
>   {
>     0 at 0. 0 at 0. 1 at 0. "right"
>     1 at 0. 1 at 0. 1 at 1. "down"
>     1 at 1. 1 at 1. 0 at 1. "left"
>     0 at 1. 0 at 1. 0 at 0. "up"
>   }
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> the following would work just as well in Balloon:
>
>   {
>     0 at 0. 0 at 0. 1 at 0. "right"
>     1 at 1. 1 at 1. 0 at 1. "left"
>     0 at 1. 0 at 1. 0 at 0. "up"
>     1 at 0. 1 at 0. 1 at 1. "down"
>   }
>
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> Since the segments form a closed outline and that is really all  
> that is required to draw them.
>
> Cheers,
>   - Andreas
>
> Noury Bouraqadi wrote:
>> Thanks Andreas for your help.
>> Do you know if there any constraints/dependencies on/between  
>> points belonging to two different segments defined for the same  
>> arrow ? Though we know about bezier curves, still we don't fully  
>> understand the implementation. We'd like to draw an open symbol,  
>> something like a "lower than" (<) symbol.
>> Noury
>> Le 7 sept. 06 à 08:30, Andreas Raab a écrit :
>>> Noury Bouraqadi wrote:
>>>> I'd like to have connectors with new arrow shapes (circles,  
>>>> arcs, rhombus...)
>>>> How can do that? Together with Serge, we had a look on class  
>>>> methods such as NCAAConnectorMorph class>>#basicArrow (see code  
>>>> below).
>>>> But, we could not figure-out how to easily and cleanly change  
>>>> the points to have the expected shape.
>>>
>>> This is a quadratic bezier curve. Each segment is made up by  
>>> three consecutive points where the first and the third point are  
>>> start and end and the intermediate is a control point that  
>>> describes how the curve is shaped. To draw straight lines, have  
>>> the intermediate point coincide with either start or end. See  
>>> also (but for cubic beziers) the description at wikipedia:
>>>
>>>   http://en.wikipedia.org/wiki/Bezier_curve
>>>
>>> On a related note, be advised that non-rational bezier curves  
>>> cannot truthfully approximate circles and other conic sections.  
>>> To approximate ellipses see Bezier2Segment  
>>> class>>makeEllipseSegments: in the 3.9 graphics package. The  
>>> points you see in Ned's spec are the control points of such  
>>> segments (this may be helpful with exploring the exact shape you  
>>> are trying to construct).
>>>
>>> Hope this helps,
>>>   - Andreas
>>>
>> ------------------------------------------------------------------
>> Dr. Noury Bouraqadi - Enseignant/Chercheur
>> ARMINES - Ecole des Mines de Douai - Dept. I.A.
>> http://csl.ensm-douai.fr/noury
>> European Smalltalk Users Group Board
>> http://www.esug.org
>> Squeak: a Free Smalltalk
>> http://www.squeak.org
>> ------------------------------------------------------------------
>
>

------------------------------------------------------------------
Dr. Noury Bouraqadi - Enseignant/Chercheur
ARMINES - Ecole des Mines de Douai - Dept. I.A.
http://csl.ensm-douai.fr/noury

European Smalltalk Users Group Board
http://www.esug.org

Squeak: a Free Smalltalk
http://www.squeak.org
------------------------------------------------------------------