Window states management

Types of window states in picom

Raw window states

These are window states tracked by the X server. They might or might not be stored directly in struct managed_win.

Name	Description	Availability in events
Properties	Window properties, the ones you can view with xprop	PropertyNotify, only tells us if the property is changed or deleted, new property value not included
Geometry	Window size and position	ConfigureNotify, fully available
Shape	Shape of a non-rectangular window	ShapeNotify, only tells us if the shape is changed, new shape not included
Viewability	Whether a window is mapped, is viewable	MapNotify and UnmapNotify, fully available. But all of the other states of a newly mapped window won't be available
Focus	Whether a window has input focus	FocusIn and FocusOut, fully available. But also affected by the _NET_ACTIVE_WINDOW property, so can't update in the event handler

There are also states concerning relationships between windows

Name	Description	Availability in events
Stacking order	The order of how windows are stacked on top of each other	ConfigureNotify and CirculateNotify, fully available
Hierarchy	The tree structure formed by X windows. picom only really cares about toplevel windows, but we still need to keep track of hierarchy changes	ReparentNotify, fully available. But if a previously non-toplevel window becomes toplevel, all of its other states won't be available

Mirrored raw states

Each of these states almost directly corresponds to a raw window state. They are stored in the struct manage_win.

Name	Description	Source
name	ICCCM/EWMH window name	Property, _NET_WM_NAME and WM_NAME
stacking_rank	Number of windows above current window	Stacking order
bounding_shape		Shape
bounding_shaped	Whether the current window is Shaped	Shape
window_type	EWMH window types	Property, _NET_WM_WINDOW_TYPE
leader	ICCCM window group leader	Property, WM_CLIENT_LEADER and WM_TRANSIENT_FOR
focused		Focus
class_instance, class_general	ICCCM window classes	Property, WM_CLASS
role	ICCCM window role	Property, WM_WINDOW_ROLE
opacity_prop	Desired opacity of window	Property, _NET_WM_WINDOW_OPACITY (not in EWMH)