XButtonEvent(3)

💅 XButtonEvent(3) — the whole Xlib event squad, explained

okay bestie, gather round 💖 this is the manual page for XButtonEvent, XKeyEvent, and XMotionEvent — aka the three event structs that handle KeyPress, KeyRelease, ButtonPress, ButtonRelease, and MotionNotify, from the XLIB FUNCTIONS corner of the universe. three structs. one girlboss family. iykyk 👑

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✨ NAME ✨

XButtonEvent, XKeyEvent, XMotionEvent — the event structures for KeyPress, KeyRelease, ButtonPress, ButtonRelease, and MotionNotify. literally the whole point of this page 🎀

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🦋 STRUCTURES 🦋

so the structures for KeyPress, KeyRelease, ButtonPress, ButtonRelease, and MotionNotify events contain this, no cap:

typedef struct {
        int type;       /* ButtonPress or ButtonRelease */
        unsigned long serial;   /* # of last request processed by server */
        Bool send_event;        /* true if this came from a SendEvent request */
        Display *display;       /* Display the event was read from */
        Window window;  /* “event” window it is reported relative to */
        Window root;    /* root window that the event occurred on */
        Window subwindow;       /* child window */
        Time time;      /* milliseconds */
        int x, y;       /* pointer x, y coordinates in event window */
        int x_root, y_root;     /* coordinates relative to root */
        unsigned int state;     /* key or button mask */
        unsigned int button;    /* detail */
        Bool same_screen;       /* same screen flag */
} XButtonEvent;
typedef XButtonEvent XButtonPressedEvent;
typedef XButtonEvent XButtonReleasedEvent;

and then the keyboard twin, same energy, different detail field:

typedef struct {
        int type;       /* KeyPress or KeyRelease */
        unsigned long serial;   /* # of last request processed by server */
        Bool send_event;        /* true if this came from a SendEvent request */
        Display *display;       /* Display the event was read from */
        Window window;  /* “event” window it is reported relative to */
        Window root;    /* root window that the event occurred on */
        Window subwindow;       /* child window */
        Time time;      /* milliseconds */
        int x, y;       /* pointer x, y coordinates in event window */
        int x_root, y_root;     /* coordinates relative to root */
        unsigned int state;     /* key or button mask */
        unsigned int keycode;   /* detail */
        Bool same_screen;       /* same screen flag */
} XKeyEvent;
typedef XKeyEvent XKeyPressedEvent;
typedef XKeyEvent XKeyReleasedEvent;

and the mouse-girlie that just moves around ✨:

typedef struct {
        int type;       /* MotionNotify */
        unsigned long serial;   /* # of last request processed by server */
        Bool send_event;        /* true if this came from a SendEvent request */
        Display *display;       /* Display the event was read from */
        Window window;  /* “event” window reported relative to */
        Window root;    /* root window that the event occurred on */
        Window subwindow;       /* child window */
        Time time;      /* milliseconds */
        int x, y;       /* pointer x, y coordinates in event window */
        int x_root, y_root;     /* coordinates relative to root */
        unsigned int state;     /* key or button mask */
        char is_hint;   /* detail */
        Bool same_screen;       /* same screen flag */
} XMotionEvent;
typedef XMotionEvent XPointerMovedEvent;

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🌸 when you actually receive these events…

when you receive these events, their structure members get set like this, bestie — pay attention, this is the good part 💅

• type — set to the event type constant name that uniquely identifies it. example incoming: when the X server reports a GraphicsExpose event to a client application, it sends an XGraphicsExposeEvent structure with the type member set to GraphicsExpose. slay, consistent.
• display — set to a pointer to the display the event was read on.
• send_event — set to True if the event came from a SendEvent protocol request.
• serial — set from the serial number reported in the protocol, but expanded from the 16-bit least-significant bits to a full 32-bit value. glow-up from 16 to 32, we love to see it 🔥
• window — set to the window that is most useful to toolkit dispatchers.

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🧚 the common members, aka the shared genes

these structures have the following common members: window, root, subwindow, time, x, y, x_root, y_root, state, and same_screen. all of them. every single one. let's go 🫶

• window — set to the window on which the event was generated, and it's referred to as the event window. as long as the conditions previously discussed are met, this is the window used by the X server to report the event.
• root — set to the source window's root window.
• x_root and y_root — set to the pointer's coordinates relative to the root window's origin at the time of the event.

then there's same_screen 🌈 — set to indicate whether the event window is on the same screen as the root window, and it can be either True or False. if True, the event and root windows are on the same screen. if False, the event and root windows are not on the same screen. simple as that, no notes.

and if the source window is an inferior of the event window, the subwindow member of the structure is set to the child of the event window that is the source window, or the child of the event window that is an ancestor of the source window. otherwise, the X server sets the subwindow member to None. and time is set to the time when the event was generated, expressed in milliseconds ⏱️

if the event window is on the same screen as the root window, the x and y members are set to the coordinates relative to the event window's origin. otherwise? these members are set to zero. zero. nothing. nada 💀

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👑 the state member

state is set to indicate the logical state of the pointer buttons and modifier keys just prior to the event — which is the bitwise inclusive OR of one or more of these button or modifier key masks:

• Button1Mask
• Button2Mask
• Button3Mask
• Button4Mask
• Button5Mask
• ShiftMask
• LockMask
• ControlMask
• Mod1Mask
• Mod2Mask
• Mod3Mask
• Mod4Mask
• Mod5Mask

all thirteen of them, listed, accounted for, not one skipped. periodt 💜

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🎀 the detail member (it changes name depending on who's asking)

each of these structures also has a member that indicates the detail. and here's the tea: the name is different per struct 😭

• for the XKeyPressedEvent and XKeyReleasedEvent structures, this member is called keycode. it's set to a number that represents a physical key on the keyboard. the keycode is an arbitrary representation for any key on the keyboard (see sections 12.7 and 16.1). yeah, go read those, i'll wait 📖
• for the XButtonPressedEvent and XButtonReleasedEvent structures, this member is called button. it represents the pointer button that changed state and can be the Button1, Button2, Button3, Button4, or Button5 value.
• for the XPointerMovedEvent structure, this member is called is_hint. it can be set to NotifyNormal or NotifyHint.

three structs, three names for basically the same slot. it's giving "we ran out of naming ideas" but honestly? iconic anyway 💅

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🔍 SEE ALSO 🔍

the whole extended family, all of them, in order, because we don't leave anyone out:

XAnyEvent(3), XCreateWindowEvent(3), XCirculateEvent(3), XCirculateRequestEvent(3), XColormapEvent(3), XConfigureEvent(3), XConfigureRequestEvent(3), XCrossingEvent(3), XDestroyWindowEvent(3), XErrorEvent(3), XExposeEvent(3), XFocusChangeEvent(3), XGraphicsExposeEvent(3), XGravityEvent(3), XKeymapEvent(3), XMapEvent(3), XMapRequestEvent(3), XPropertyEvent(3), XReparentEvent(3), XResizeRequestEvent(3), XSelectionClearEvent(3), XSelectionEvent(3), XSelectionRequestEvent(3), XUnmapEvent(3), XVisibilityEvent(3)

and of course: Xlib - C Language X Interface 📚

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ok that's the page!! go forth and handle your events, bestie 🌟

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💖 mwah, that's a wrap — this one's from X Version 11, libX11 1.8.14, and it's filed under XButtonEvent(3). see u in the next manpage, love u, bye 🎀✨🦋