Re: Drag image creation for NSView with CALayer in NSCollectionView calls drawRect:?
Re: Drag image creation for NSView with CALayer in NSCollectionView calls drawRect:?
- Subject: Re: Drag image creation for NSView with CALayer in NSCollectionView calls drawRect:?
- From: Lee Ann Rucker <email@hidden>
- Date: Mon, 14 Mar 2011 15:45:11 -0700
- Acceptlanguage: en-US
- Thread-topic: Drag image creation for NSView with CALayer in NSCollectionView calls drawRect:?
On Mar 14, 2011, at 1:29 PM, Kyle Sluder wrote:
> On Mon, Mar 14, 2011 at 1:15 PM, Lee Ann Rucker <email@hidden> wrote:
>> Is there something I'm missing that would cause it to create the right drag image for me?
>
> If you think about it, you pretty much have to use the old raster
> drawing path to generate drag images. Even if you don't call
> -drawRect: (which NSCollectionView presumably does to insulate you
> from its implementation details), the drag image is a static bitmap. I
> suppose you could use a CARenderer to produce a static bitmap from
> within -drawRect:.
It's a CAOpenGLLayer, so as far as I can tell CARenderer is not going to help. But I'm fine with having a placeholder image, I just wanted to be sure I was making it in the right place. The first thing I thought looked promising was cacheDisplayInRect:toBitmapImageRep: which is called by NSCollectionView's drag, but that just calls drawRect on the top level view.
>
> I believe we've determined that the window update machinery does not
> call -drawRect: if you have set up your layer-hosting view correctly.
> Printing, and apparently NSCollectionView, will call it directly.
>
> --Kyle Sluder
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