Re: Problem with Grouping the rotated object

FROM : Gordon Apple
DATE : Wed Apr 02 21:26:27 2008

Let me explain how we are handling grouped objects.

We have only one basic type of draw object with a dictionary of
characteristics.  That gives a lot of flexibility.  We do not let objects
draw themselves.  Instead, we use a separate rendering object.  This results
in a clean object data model.  (Hopefully, this will help when we do
Windows.)

We use an object of type "group" to replace grouped objects.  When the
renderer encounters a "group" type object, it creates another temporary
renderer object that draws the group.  This allows recursion for groups.  Of
course, the group object has to compute it's own bounds, including internal
and total rotations.  So far, this works quite well and we haven't
encountered the problem you have had.


> Message: 4
> Date: Wed, 2 Apr 2008 16:30:42 +0530
> From: "Ghufran Ahamad" <ghufran.<email_removed>>
> Subject: Problem with Grouping the rotated object.
> To: <<email_removed>>
> Message-ID: <20080402110120.<email_removed>>
> Content-Type: text/plain;    charset="us-ascii"
>
> Hi All,
>
>
>
> We are developing a kind of drawing application in Objective C using Cocoa
> framework. We have several separate graphical objects, each having their own
> position and rotation angle, are then grouped. As soon as we group the
> objects the rotated object has got shift with their angle. This happen only
> with rotated object. Below is the code snippet that we are using.
>