[Drawkit] two views, different layers?

[Graham Cox]

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

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.

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?