Re: MVC question
Re: MVC question
- Subject: Re: MVC question
- From: Ryan Bates <email@hidden>
- Date: Sun, 8 Feb 2004 13:18:10 -0800
On Feb 7, 2004, at 1:07 PM, Koen van der Drift wrote:
Initially I thought I can pass that info with the info on the
pasteboard to the model, more or less as in the Sketch example. But,
does this info really belong in the model? The objects shouldn't know
where they need to be drawn, the view or viewcontroller should take
care of this. Any suggestions how to approach this? Maybe use a
parallel array that stores the coordinates of each object?
A good rule of thumb is if a class has more than one purpose then it
should be split into two classes. If the model objects you are drawing
have a purpose other than to be drawn, I would create a separate
"graphic" class to handle the drawing of each model class. In Sketch,
the graphic objects only have one purpose - to be drawn - so it makes
sense to handle the drawing there.
If you do separate the two, I would make the drawing classes similar to
Sketch's. There could be an abstract graphic class which would contain
the position, size, etc. I would then create a graphic subclass for
each model object that needs to be drawn. The drawing class could hold
an instance of the model it draws.
Let's say you are drawing a clock. You could create a Clock model class
that keeps track of time. You could then create a ClockGraphic class
that draws a Clock object. You could even go a step further and create
an AnalogClockGraphic and a DigitalClockGraphic to draw the same Clock
two different ways.
An additional question, since I am rewriting the app from scratch,
would this type of app benefit from using Cocoa bindings?
I really don't know much about bindings, but it seems to be best suited
for widget-type applications. Throw bindings in with a couple buttons
and a table view and you can create a simple program with almost no
code, but when it comes to a drawing application where most of the GUI
is made up of custom objects, it might be harder to implement bindings.
I could be wrong though.
Ryan Bates
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| | >MVC question (From: Koen van der Drift <email@hidden>) |