10.4 Event Processing Overview

The event reported to a client application during event processing depends on which event masks you provide as the event-mask attribute for a window. For some event masks, there is a one-to-one correspondence between the event mask constant and the event type constant. For example, if you pass the event mask ButtonPressMask, the X server sends back only ButtonPress events. Most events contain a time member, which is the time at which an event occurred.

In other cases, one event mask constant can map to several event type constants. For example, if you pass the event mask SubstructureNotifyMask, the X server can send back CirculateNotify, ConfigureNotify, CreateNotify, DestroyNotify, GravityNotify, MapNotify, ReparentNotify, or UnmapNotify events.

In another case, two event masks can map to one event type. For example, if you pass either PointerMotionMask or ButtonMotionMask, the X server sends back a MotionNotify event.

The following table lists the event mask, its associated event type or types, and the structure name associated with the event type. Some of these structures actually are typedefs to a generic structure that is shared between two event types. Note that N.A. appears in columns for which the information is not applicable.

Event Mask	Event Type	Structure	Generic Structure
ButtonMotionMask	MotionNotify	XPointerMovedEvent	XMotionEvent
Button1MotionMask
Button2MotionMask
Button3MotionMask
Button4MotionMask
Button5MotionMask
ButtonPressMask	ButtonPress	XButtonPressedEvent	XButtonEvent
ButtonReleaseMask	ButtonRelease	XButtonReleasedEvent	XButtonEvent
ColormapChangeMask	ColormapNotify	XColormapEvent
EnterWindowMask	EnterNotify	XEnterWindowEvent	XCrossingEvent
LeaveWindowMask	LeaveNotify	XLeaveWindowEvent	XCrossingEvent
ExposureMask	Expose	XExposeEvent
GCGraphicsExposures in GC	GraphicsExpose	XGraphicsExposeEvent
	NoExpose	XNoExposeEvent
FocusChangeMask	FocusIn	XFocusInEvent	XFocusChangeEvent
	FocusOut	XFocusOutEvent	XFocusChangeEvent
KeymapStateMask	KeymapNotify	XKeymapEvent
KeyPressMask	KeyPress	XKeyPressedEvent	XKeyEvent
KeyReleaseMask	KeyRelease	XKeyReleasedEvent	XKeyEvent
OwnerGrabButtonMask	N.A.	N.A.
PointerMotionMask	MotionNotify	XPointerMovedEvent	XMotionEvent
PointerMotionHintMask	N.A.	N.A.
PropertyChangeMask	PropertyNotify	XPropertyEvent
ResizeRedirectMask	ResizeRequest	XResizeRequestEvent
StructureNotifyMask	CirculateNotify	XCirculateEvent
	ConfigureNotify	XConfigureEvent
	DestroyNotify	XDestroyWindowEvent
	GravityNotify	XGravityEvent
	MapNotify	XMapEvent
	ReparentNotify	XReparentEvent
	UnmapNotify	XUnmapEvent
SubstructureNotifyMask	CirculateNotify	XCirculateEvent
	ConfigureNotify	XConfigureEvent
	CreateNotify	XCreateWindowEvent
	DestroyNotify	XDestroyWindowEvent
	GravityNotify	XGravityEvent
	MapNotify	XMapEvent
	ReparentNotify	XReparentEvent
	UnmapNotify	XUnmapEvent
SubstructureRedirectMask	CirculateRequest	XCirculateRequestEvent
	ConfigureRequest	XConfigureRequestEvent
	MapRequest	XMapRequestEvent
N.A.	ClientMessage	XClientMessageEvent
N.A.	MappingNotify	XMappingEvent
N.A.	SelectionClear	XSelectionClearEvent
N.A.	SelectionNotify	XSelectionEvent
N.A.	SelectionRequest	XSelectionRequestEvent
VisibilityChangeMask	VisibilityNotify	XVisibilityEvent

The sections that follow describe the processing that occurs when you select the different event masks. The sections are organized according to these processing categories:

• Keyboard and pointer events

• Window crossing events

• Input focus events

• Keymap state notification events

• Exposure events

• Window state notification events

• Structure control events

• Colormap state notification events

• Client communication events

Next: Keyboard and Pointer Events

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Christophe Tronche, [email protected]