Re: Scrollers on custom view appearing but not disappearing

FROM : Steve Weller
DATE : Sat Mar 01 03:10:01 2008

On Feb 29, 2008, at 4:46 PM, Quincey Morris wrote:

>
> On Feb 29, 2008, at 16:00, Steve Weller wrote:
>

>> - (void) setFrameSize:(NSSize)newSize
>> {
>>     NSSize cSize;
>>     cSize = [self canvasSize];  // Provides a size
>>
>>     // Use the larger dimensions of the two rects
>>     if(newSize.width > cSize.width)
>>         cSize.width = newSize.width;
>>     if(newSize.height > cSize.height)
>>         cSize.height = newSize.height;
>>     
>>      [super setFrameSize:cSize];
>> }
>>
>> And this works as long as the window is only made smaller. If the 
>> window is made larger then the scrollers do not disappear.
>>
>> Is my approach the right one for what I am trying to achieve?

>
> Probably not. There are various ways the view frame can change, and 
> they don't all funnel through the setFrameSize method.
>
> If you register to receive NSViewFrameDidChangeNotification's for 
> your view (remembering to call setPostsFrameChangedNotifications: 
> YES), it might work to do something like this in the notification 
> method:
>
>     [[NSNotificationCenter defaultCenter] removeObserver: self];
>     NSRect frame = [self frame];
>     // calculate new frame
>     [self setFrame: frame];
>     [[NSNotificationCenter defaultCenter] addObserver: self ...
>



I implemented this with no change no behavior.

The higher level problem I am trying to solve is this:

My custom view spans the window's content view. I want to draw a white 
rectangle (think of a document) centered in that area and fill the 
remainder gray. In my drawRect method I first draw gray into the 
rectangle passed. Then I calculate where the white rectangle should be 
and draw it.

I need the scrollers to act on the bounds of the white rectangle so 
that they are present when any part of it is not visible.

Should I be putting my custom view inside another view and doing the 
centering and background color with IB instead?

What is the best way of implementing this?