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Re: wits end with nsview and nsrectfill()
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Re: wits end with nsview and nsrectfill()


  • Subject: Re: wits end with nsview and nsrectfill()
  • From: Graham Cox <email@hidden>
  • Date: Fri, 05 Dec 2014 08:44:16 +1100

> On 5 Dec 2014, at 1:43 am, Navneet Kumar <email@hidden> wrote:
>
> 1. If a view is send the msg -display, is the msg sent to all its subviews without exception?
> 2. Could it be that so many views when trying to display (in the main thread of course), could block some views from refreshing altogether?
>
> If I could get a few pointers, I might get to the bottom of this problem.


Are *you* sending the -display message? Why? It's very unusual to do that.

The normal way to update a view is to mark as needing display with -setNeedsDisplay:, then the main loop causes redisplay as part of its normal functioning. Note that many types of view subclass, such as controls (including text fields) invoke -setNeedsDisplay: as part of setting a new value, so you only need to do this for custom view subclasses or other special requirements.

Unlike -display, it's harmless to "over invoke" -setNeedsDisplay, as there will still only be one redisplay per main cycle. If your code is calling -display directly, then it's probable that views are getting repainted too much, and that's often a problem for anything containing text or transparent backgrounds, because pixels get painted over more than once, darkening them. Sounds like what you could be seeing.

TL; DR: if you're invoking -display, you're doing it wrong™

--Graham



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 >Re: wits end with nsview and nsrectfill() (From: Navneet Kumar <email@hidden>)

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