Cocoa & custom view

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Paul - 28 Jul 2006 08:05 GMT

Hi,

In "myView" which is a custom view, drawRect is drawing a few objects at
100 pixels from the left edge of the view. When I click the mouse on one
of these objects the outline is displayed in a different colour but the
it's is being drawn 100 pixels from the left edge of the window not 100
pixels from the left edge of the view.

What am I doing wrong? Any help appreciated.

Paul

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Just - 28 Jul 2006 09:17 GMT

> Hi,
>
[quoted text clipped - 5 lines]
>
> What am I doing wrong? Any help appreciated.

Are you calling drawRect yourself?

It's impossible to say what you're doing wrong if you don't post any
code.

Just

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Tom Harrington - 28 Jul 2006 16:40 GMT

> Hi,
>
[quoted text clipped - 5 lines]
>
> What am I doing wrong? Any help appreciated.

Hard to say from just that description, but at a guess you're probably
forgetting to convert from the window's coordinates to the view's
coordinates at some point. One of the -convertRect: or -convertPoint:
methods may be what you need.

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Tom "Tom" Harrington
Macaroni, Automated System Maintenance for Mac OS X.
Version 2.0: Delocalize, Repair Permissions, lots more.
See http://www.atomicbird.com/

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Paul - 29 Jul 2006 06:35 GMT

Maybe it's because I'm drawing the object outside the custom view's
drawRect so it's just drawing to the window not the view. I'm drawing it
in the view's mouseDown. I'll have a fiddle with the code.

Thanks,

Paul

> > Hi,
> >
[quoted text clipped - 10 lines]
> coordinates at some point. One of the -convertRect: or -convertPoint:
> methods may be what you need.

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John C. Randolph - 29 Jul 2006 09:06 GMT

> Maybe it's because I'm drawing the object outside the custom view's
> drawRect so it's just drawing to the window not the view. I'm drawing it
> in the view's mouseDown.

Don't do that, and don't send -drawRect: yourself.

In -mouseDown:, process the event. If you determine upon doing so that
you want to change what you see in your view, then send
-setNeedsDisplay: or -setNeedsDisplayInRect: to the view in question.

You also appear to be confused when you refer to the "custom view's
drawRect". A view has a bounds rect and a frame rect. A view
implements -drawRect:. The rect passed to a view in a -drawRect:
message is dependent on what portion of the view needs to be redrawn;
this might be the entire bounds of the view, or it might be less than
that.

I strongly recommend reading the concept docs on views and 2D drawing.
It will save you a good deal of time.

-jcr

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Michael Ash - 29 Jul 2006 12:15 GMT

> Maybe it's because I'm drawing the object outside the custom view's
> drawRect so it's just drawing to the window not the view. I'm drawing it
> in the view's mouseDown. I'll have a fiddle with the code.

"Hard to say from just that description" is a very polite and roundabout
way of asking you to *post your code*. It's impossible to to answer this
sort of question with any certainty without actually seeing the code
responsible for the behavior. The best we can do without code is give you
vague platitudes which may or may not apply, whereas if we have code then,
assuming the problem is clear in the code (usually but not always the
case) then we can both point out the the specific error and the conceptual
problem that caused you to write it.

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Michael Ash
Rogue Amoeba Software

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Simon Slavin - 30 Jul 2006 22:06 GMT

On 28/07/2006, Paul wrote in message
<1hj7325.1pvboanb8ealaN%paulfredlein@NOSPAMoptusnet.com.au>:

> In "myView" which is a custom view, drawRect is drawing a few objects at
> 100 pixels from the left edge of the view.

So what you're saying here is that when drawRect is called normally
(because your window has just appeared) the object you're drawing appears
in its expect place, right ?

> When I click the mouse on one
> of these objects

'one of these objects' being one of your custom views, right ?

> the outline is displayed in a different colour but the
> it's is being drawn 100 pixels from the left edge of the window not 100
> pixels from the left edge of the view.

The need to redraw the contents of the custom view must be something
you're doing in your code because there's not normally any need to redraw
something just because someone clicks on it. So you must have some code
somewhere which responds to a mouse click by calling the drawRect method.

So what parameters are you passing to it as its (NSRect) argument when you
call it ?

Simon.

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http://www.hearsay.demon.co.uk

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Paul - 31 Jul 2006 05:31 GMT

Hi,

Found the problem.

When I clicked the mouse in my object the object called:
"NSFrameRectWithWidthUsingOperation" immediately and drew the rect which
is outside the view's drawRect function.

So I made the mouseDown change the preset colour of my object and then
called: [self setNeedsDisplay:YES] after the mouseDown and then the view
refreshed itself and drew the rect in the proper place in the view not
in the window.

Thanks,

Paul

> Hi,
>
[quoted text clipped - 7 lines]
>
> Paul

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Mac Forum / Programming / Mac Programming / July 2006

Cocoa & custom view