Currently, the Workspace has no any api to constrain one window above
another. This results in having hacks such as keepDeletedTransientAbove()
This change introduces a basic api to constrain a given window above
another. It can be used for ensuring that transient windows are placed
above their parents. It also can be used for stacking the outline window
below the move-resize window.
Internal windows may also have transient parents. Because of that, this
change makes the workspace add internal clients to the stacking order by
default. The good thing about it is that it allows us unify some input
related code for "external" windows and internal windows.
Once in a while, we receive complaints from other fellow KDE developers
about the file organization of kwin. This change addresses some of those
complaints by moving all of source code in a separate directory, src/,
thus making the project structure more traditional. Things such as tests
are kept in their own toplevel directories.
This change may wreak havoc on merge requests that add new files to kwin,
but if a patch modifies an already existing file, git should be smart
enough to figure out that the file has been relocated.
We may potentially split the src/ directory further to make navigating
the source code easier, but hopefully this is good enough already.
