> > We went through this in #blackbox a couple of months ago. You see it in > reverse with applications like aterm remembering old backgrounds: > > 1. use bsetroot to set the background. > 2. aterm et al respect the background setting and transparency works. > 3. Eterm complains about unsupported transparency. > > Now use Esetroot to set the background... > > 4. all applications respect the background and transparency works > > Now change the background again, with, for example, display... > > 5. all applications continue to use the old background (cookie cutter > effect). > > Esetroot sets some property on the root window that the rest do not. Only > Eterm seems to care whether or not that property is set or not. Some nice > person in #blackbox (I disremember who) inspected the properties set on the > root window by various utilities, and came up with the attached to reset > whatever Esetroot does that the others do not (to get rid of the cookie > cutter effect). >
So, I was a E hacker way back when and saw the birth of Eterm. I even used to work with its author (ick). When Eterm was created it was realized that there is NO way to find out what the root looks like. So they made an app which sets an Atom that others apps (liek Eterm) can query. Once Eterm's psuedo transparency became popular other people used the idea. So this is how xchat and other apps achieve the same thing. Note that same apps (xv) do not set this Atom which is why Eterm does not work with xv. aterm codes a fall back. If the Atom is not set, it sets its background to ParentRelative which mimics the root window. This however does not work as well. The proper solution is for bsetroot to properly set the Atoms that the transparent apps want.
