You should look at the Morph hierarchy. In the Pharo Collaborative and Pharo By Examples books there are chapters worth reading. You may also want to learn from DrGeo sour code but it is a hudge beast and probably not the easier path. Hilaire -- Dr. Geo http://drgeo.eu

Look at PolygonMorph. Stef On Mar 20, 2013, at 11:03 AM, sminni <sm@planage.com> wrote:

Hi

I have a small project (a real requirement) and I want a little guidance to do it (myself) - pl. assume I am new to pharo though I can navigate the IDE & have a background in O-O development.

1. Draw a triangle with draggable handles on points 2. The sides length and angles will be displayed (in editable fields) 3. We can lock any of the sides / angles 4. If the side / angle is edited then an action can be initiated to recomplete the triangle by redrawing the side clicked next

Thanks Sanjay

----- --- Regards, Sanjay -- View this message in context: http://forum.world.st/new-learning-project-tiangle-with-draggable-points-on-... Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

There are two ways to approach this problem: * Spatial * Vector *Spatial:* As per the pharo by example pdf, you can create a custom TriangleMorph ( they have a cross ). Add the behavior that you mention to the TriangleMorphWithAttributes that holds the plain triangle morph. So on change to the attributes it will modify the triangle. There are challenges to using angle / other geometric approaches in the above, but simple and probably a day's effort. Good for Kid's / early school graphics I am not sure but many other contributions, half way done are there which do have some works in this line of thought including one on Kinesthetics with balls that have a gravity like pull etc.. which are quite good enough. *Vector: * CAD/ Dr. Geo approach: Use a line that makes a Triangle. Perhaps may need to add a surface for color fill also. Typical in CAD is to create a polyline that makes an arbitrary line collection with several points as input. If its closed you can treat it as an arbitrary polygon with recognition of the bounded surface for color fill. You will then need to do something similar to above to have custom change shape on attribute changes. The offside here is it will be time consuming and will need to use standard vector formulae's for accuracy with sin / cos transformation as you deal with angles. If you want this, better be sure about the whole requirement, you might reinvent the Dr. Geo work.. better to study works done in say VW for .dxf reading / display / CAD package completely once before embarking on this route. On Wed, Mar 20, 2013 at 3:33 PM, sminni <sm@planage.com> wrote:

Hi

I have a small project (a real requirement) and I want a little guidance to do it (myself) - pl. assume I am new to pharo though I can navigate the IDE & have a background in O-O development.

1. Draw a triangle with draggable handles on points 2. The sides length and angles will be displayed (in editable fields) 3. We can lock any of the sides / angles 4. If the side / angle is edited then an action can be initiated to recomplete the triangle by redrawing the side clicked next

Thanks Sanjay

----- --- Regards, Sanjay -- View this message in context: http://forum.world.st/new-learning-project-tiangle-with-draggable-points-on-... Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.