Raster layer opacity

[Daniel Calvelo Aros]

From: Jonathan Coles <jonathan at jpcoles.com>
Sent: Wed, 23 Mar 2005 10:41:44 -0500
>
> Here'a question: Is opacity a property of all layers or just raster
> layers? perhaps we can't support opacity in vectors layers just yet, 
> but should that mean we shouldn't anticipate it? If opacity is a 
> property of all layers then I can refactor the opacity methods in 
> RasterLayer into BaseLayer.

I'd say opacity should be considered for vectors as well. Imagine the
possibility of visually several merging polygonal filled areas with raster
background info.

I'm not sure what must be done about it, though.

BTW, has anyone looked at the Anti-Grain Geometry library
(http://antigrain.com)? How difficult would it be to use that for rendering to
a bitmap and copy this into a DC instead of using wxDC functions? Is the cost
of such a development worth the gain of antialiasing and transparency?

Daniel.

PS. For a very nice application of agg, see http://matplotlib.sourceforge.net,
and particularly
http://matplotlib.sourceforge.net/matplotlib.toolkits.basemap.basemap.html