[Qt-interest] sketcher program

[phil prentice]

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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