[Qt-interest] sketcher program

[Mihail Naydenov]

Define "data  duplication"?  You can aways "bake" information - draw an item 
yourself, instead of using lots and lots of items (in which GS is actually very 
good at). 



MihailNaydenov


----- Original Message ----
> From: phil prentice <philp.cheer at talktalk.net>
> To: qt-interest at qt.nokia.com
> Sent: Sat, May 7, 2011 10:13:48 AM
> Subject: Re: [Qt-interest] sketcher program
> 
> Having now had a bit more of a read, I now realise that  I should use the 
> QGraphicsView class. I think that I got side-tracked by the Model-View 
> architecture. because I wanted to understand it a lot more.  However it  looks 

> like the QGraphicsView class will do most of what I need.  I  still have one 
> question.  It looks like that I will need to create a  scene with loads of QT 
> graphics items in it.  Suppose I have a database  (e.g. a garden design) which 

> has loads of other information in it (plant  types, soil types etc) would this 

> mean that you would end up with data  duplication i.e. each item would hold 
> duplicate data of element positioning  as your main database.  Is that just 
> something that you would except as  part of the design?  I think the answer is 

> probably yes, because as a  result you get the extra functionality of the 
> graphics items?  As a  result though if your database is massive then there 
> would be a lot of data  duplication.  Anyway I will start writing the app 
> using the  QGraphicsView class.
> 
> Thanks again
> 
> 
> On Friday 06 May 2011 20:03,  phil prentice wrote:
> > Hi
> >   Recently I have been looking at  an MFC example of a program that lets you
> > draw lines, circles, polylines  etc in an MDI.  As a little exercise for
> > myself I have decided to  try to perform the same functionality using Qt.
> > (I know its probably  already been done, but I would like to go through the
> > exercise myself to  try and learn!!)
> > I have some very basic questions about the model view  architecture.
> > And I need to read a lot more.
> > I would eventually  like to create a Model view (QStandardItem model or a
> > custom model), but  to start with I thought that I might try and use the
> > item view  conveniance classes.
> >
> > I was thinking of using  QListWidget.
> > I was thinking of deriving an element base class from  QListWidgetItem and
> > then deriving line, circle etc from the element  base(using a virtual draw
> > function for each element)
> >
> > I  would then use setItemDelegate for editing/displaying the  elements.
> >
> > Is this a stupid idea?
> > Would this be very  inefficient?
> >
> > I know that QListWidget is normally used to store  text and icons, so if I
> > extend it like this its probably not the way to  do things?
> >
> > Thanks
> >
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