PNG image files with alpha channel

[Miles Bader <miles.bader@necel.com>]

Is Emacs supposed to properly handle an alpha channel in a PNG file?

I vaguely recall that it used to do something halfway reasonable (even
if just merging in the default bg color), but now it seem to simply
ignore an alpha channel.

E.g., using default settings, with a white background, do:

   (insert-image (create-image "image-with-alpha.png"))

[The create-image :background parameter seems to have no effect either.]


If you don't have an alpha-channel-bearing image, try this:

   http://download.savannah.gnu.org/releases/emacs/icons/emacs5-256.png

The "background" around the sphere has an alpha channel that's mostly zero.

Thanks,

-Miles

-- 
Politeness, n. The most acceptable hypocrisy.