[cairo] Wanted features in Cairo.

[Miguel de Icaza]

Hey folks,

    As part of our effort to implement Silverlight in Linux we have run
into a few things that would be nice to have in Cairo and Behdad
suggested that I post these to the list.

* Line caps

    A feature that we are currently missing is the ability to use
different line caps for the beginning and end of a drawing.   Cairo
currently only offers one option: cairo_set_line_cap and we would need
to have separate versions for the beginning and end.

* Alpha painting

    Currently Cairo has a couple of functions for setting its source: 

	set_source_rgb
	set_source_rgba    <- With alpha

	set_source	   <- from pattern
	set_source_surface <- from surface

    We would like to have parity in set_source and set_source_surface in
terms of using the pattern/surface with an alpha channel.

    It is not absolutely mandatory to have them, but it would clean up
some of the code that we have right now and the creation of temporary
buffers to get the painting on the screen with alpha transparency.

We will try to provide some more feedback as we get more solid data for
you guys regarding performance.

Miguel.