[Qt-interest] Qt/C++ working with graphicsview

[Ross Driedger]

On 24-Jan-10, at 11:32 AM, qt-interest-request at trolltech.com wrote:

> Message: 2
> Date: Sun, 24 Jan 2010 09:30:28 -0600
> From: "Stephen Deetz" <stephendeetz at chibardun.net>
> Subject: [Qt-interest] Qt/C++ working with graphicsview.
> To: <qt-interest at trolltech.com>
> Message-ID: <005a01ca9d0a$28b477b0$7a1d6710$@net>
> Content-Type: text/plain; charset="us-ascii"
>
> Trying to get used to Qt/C++ by working with graphicsview.
>
>
>
> Main question: How does a scene connect to an item for mouse events?

Until you fix the C++ issues, it is pointless to sweat the Qt details.

> Other questions:
>
> 1)  Am I using the inherited stuff correctly?

No.  There is no point in deriving a new class unless you add  
something new to it.  The coordinates are stored in the subclass.

> a.  Calling the super classes.

No.  Look up 'initiation lists' in a good C++ reference.

> b.  Virtual keyword needed for subclass only if planning on making
> descendents?

No.  Look up 'late binding' in a good C++ reference.  I gather from  
your terminology that you have some Java experience.  Java does not  
have this issue.

> 2)  I think I know what bounding rect is, but why is it needed if  
> shape is
> used for collisions?

??

I don't understand your question.  I do some fairly intricate graphics  
(music notation) and need to check for more than collisions

> 3)  Qreal to int conversion. Is this a problem?

Everything to the right of the decimal will be lost.  A good compiler  
will warn you of this if you have the warnings on -- which you should.

Ross

"Sometimes I think the surest sign that intelligent life exists  
elsewhere in the universe is that none of it has tried to contact us."
Bill Waterson (Calvin & Hobbes)

Ross Driedger
ross_at_earz.ca




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