xfdesktop transparent background

[Didier Trosset]

Hello,

I've been trying to add a transparent background color style option to 
xfdesktop. I managed to get it in the setting panel, along with the .po 
files for the translations, got it compiled and installed (from 
os-cillation debian source packages).

But then, when it comes to implement it I tried several options but 
always got into having a non transparent background.

1) I changed xfce_backdrop_get_pixbuf (in xfce-backdrop.c) to return a 
NULL GdkPixbuf. Shows a white background.

2) I changed this function to return a creat_solid of 0x0 pixels. Shows 
a white background.

3) I changed this function to return a creat_solid of 1x1 pixels. Shows 
a 'color_1' background.

4) Having this function returning a GdkPixbuf created by a new function 
create_transparent. This function (similar to create_solid) use 
gdk_pixbuf new with TRUE for the has_alpha parameter. But when the 
transparency (alpha) is set to maximum, whetever the other colors 
components I put, the background is black and not transparent.

Could someone give me a hint on how to do this?

Thanks
Didier