[Drawkit] two views, different layers?

[James Maxwell]

On 28-Jul-08, at 4:46 AM, Graham Cox wrote:

> Layers don't have an alpha channel, because they are not bitmaps.

Ah, okay. Sorry. I don't really know much about graphics, yet. But I'm  
getting better!
>
>
> I guess what you're getting at is whether it's possible to fade all  
> objects in a layer simultaneously. You could achieve that using a  
> special style or rasterizer class that picked up a common alpha  
> value from the layer and apply that value in every place that it  
> does drawing. Messy. An alternative would be to capture the layer  
> contents in an image and then draw the image with the desired alpha  
> - this approach is likely to work a lot better but beware of  
> pixelisation at higher zoom factors. Object drawing layers already  
> have a mechanism for capturing their contents in either or both of  
> an NSPDFImageRep and a CGLayer, you might be able to leverage that  
> code.

hmm... This is all sounding much more complex than just going ahead  
with my original idea of two separate drawings. I think I'd better  
stick with that, for now, and see what sorts of obstacles I come up  
against.

thanks again.

J.


>
>
> cheers, Graham
>
>
> On 28 Jul 2008, at 5:44 pm, James Maxwell wrote:
>
>> I don't suppose it's possible to set a layer's alpha channel, is it?
>
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