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 Xmbuf(Xext)       X Version 11 (Release 5) 6 January 1993        Xmbuf(Xext)


 Name

    Xmbuf - X multibuffering functions

 Syntax


    #include <X11/extensions/multibuf.h>

    Bool XmbufQueryExtension(
        Display *dpy,
        Display *dpy,
        int *event_base_return,
        int *error_base_return);

    Status XmbufGetVersion(
        Display *dpy,
        int *major_version_return,
        int *minor_version_return);

    int XmbufCreateBuffers(
        Display *dpy,
        Window window,
        int count,
        int update_action,
        int update_hint,
        Multibuffer *buffers_update);

    void XmbufDestroyBuffers(
        Display *dpy,
        Window window);

    void XmbufDisplayBuffers(
        Display *dpy,
        int count,
        Multibuffer *buffers,
        int min_delay,
        int max_delay);

    Status XmbufGetWindowAttributes(
        Display *dpy,
        Window window,
        XmbufWindowAttributes *attributes);

    void XmbufChangeWindowAttributes(
        Display *dpy,
        Window window,
        unsigned long valuemask,
        XmbufSetWindowAttributes *attributes);

    Status XmbufGetBufferAttributes(
        Display *dpy,
        Multibuffer buffer,
        XmbufBufferAttributes *attributes);

    void XmbufChangeBufferAttributes(
        Display *dpy,
        Multibuffer buffer,
        unsigned long valuemask,
        XmbufSetBufferAttributes *attributes);

    Status XmbufGetScreenInfo(
        Display *dpy,
        Drawable drawable,
        int *nmono_return,
        XmbufBufferInfo **mono_info_return,
        int *nstereo_return,
        XmbufBufferInfo **stereo_info_return);

    Window XmbufCreateStereoWindow(
        Display *dpy,
        Window parent,
        int x,
        int y,
        unsigned int width,
        unsigned int height,
        unsigned int border_width,
        int depth,
        unsigned int class,                 /* InputOutput, InputOnly*/
        Visual *visual,
        unsigned long valuemask,
        XSetWindowAttributes *attributes,
        Multibuffer *left_return,
        Multibuffer *right_return);


 Structures

    Events:

    typedef struct {
        int type;   /* of event */
        unsigned long serial;       /* # of last request processed by server */
        int send_event;     /* true if this came frome a SendEvent request */
        Display *display;   /* Display the event was read from */
        Multibuffer buffer; /* buffer of event */
        int state;  /* see Clobbered constants above */
    } XmbufClobberNotifyEvent;

    typedef struct {
        int type;   /* of event */
        unsigned long serial;       /* # of last request processed by server */
        int send_event;     /* true if this came frome a SendEvent request */
        Display *display;   /* Display the event was read from */
        Multibuffer buffer; /* buffer of event */
    } XmbufUpdateNotifyEvent;

    Per-window attributes that can be got:

    typedef struct {
        int displayed_index;        /* which buffer is being displayed */
        int update_action;  /* Undefined, Background, Untouched, Copied */
        int update_hint;    /* Frequent, Intermittent, Static */
        int window_mode;    /* Mono, Stereo */
        int nbuffers;       /* Number of buffers */
        Multibuffer *buffers;       /* Buffers */
    } XmbufWindowAttributes;

    Per-window attributes that can be set:

    typedef struct {
        int update_hint;    /* Frequent, Intermittent, Static */
    } XmbufSetWindowAttributes;

    Per-buffer attributes that can be got:

    typedef struct {
        Window window;      /* which window this belongs to */
        unsigned long event_mask;   /* events that have been selected */
        int buffer_index;   /* which buffer is this */
        int side;   /* Mono, Left, Right */
    } XmbufBufferAttributes;

    Per-buffer attributes that can be set:

    typedef struct {
        unsigned long event_mask;   /* events that have been selected */
    } XmbufSetBufferAttributes;

    Per-screen buffer info (there will be lists of them):

    typedef struct {
        VisualID visualid;  /* visual usuable at this depth */
        int max_buffers;    /* most buffers for this visual */
        int depth;  /* depth of buffers to be created */
    } XmbufBufferInfo;


 Description

    The application programming library for the X11 Double-Buffering, Multi-
    Buffering, and Stereo Extension contains the interfaces described below.
    With the exception of XmbufQueryExtension, if any of these routines are
    called with a display that does not support the extension, the Exten-
    sionErrorHandler (which can be set with XSetExtensionErrorHandler and
    functions the same way as XSetErrorHandler) will be called and the func-
    tion will then return.

    XmbufQueryExtension returns True if the multibuffering/stereo extension
    is available on the given display. If the extension exists, the value of
    the first event code (which should be added to the event type constants
    MultibufferClobberNotify and MultibufferUpdateNotify to get the actual
    values) is stored into event_base_return and the value of the first error
    code (which should be added to the error type constant MultibufferBad-
    Buffer to get the actual value) is stored into error_base_return.

    XmbufGetVersion gets the major and minor version numbers of the exten-
    sion. The return value is zero if an error occurs or non-zero if no error
    happens.

    XmbufCreateBuffers requests that ``count'' buffers be created with the
    givenupdateaction and updatehint and be associated with the indicated
    window. The number of buffers created is returned (zero if an error
    occurred) and buffers_update is filled in with that many Multibuffer
    identifiers.

    XmbufDestroyBuffers destroys the buffers associated with the given win-
    dow.

    XmbufDisplayBuffers displays the indicated buffers their appropriate win-
    dows within max_delay milliseconds after min_delay milliseconds have
    passed.  No two buffers may be associated with the same window or else a
    Matc error is generated.

    XmbufGetWindowAttributes gets the multibuffering attributes that apply to
    all buffers associated with the given window.  The list of buffers
    returns may be freed with XFree.  Returns non-zero on success and zero if
    an error occurs.

    XmbufChangeWindowAttributes sets the multibuffering attributes that apply
    to all buffers associated with the given window. This is currently lim-
    ited to the update_hint.

    XmbufGetBufferAttributes gets the attributes for the indicated buffer.
    Returns non-zero on success and zero if an error occurs.

    XmbufChangeBufferAttributes sets the attributes for the indicated buffer.
    This is currently limited to the event_mask.

    XmbufGetScreenInfo gets the parameters controlling how mono and stereo
    windows may be created on the screen of the given drawable. The numbers
    of sets of visual and depths are returned in nmono_return and
    nstereo_return. If nmono_return is greater than zero, then
    mono_info_return is set to the address of an array of XmbufBufferInfo
    structures describing the various visuals and depths that may be used.
    Otherwise, mono_info_return is set to NULL. Similarly, stereo_info_return
    is set according to nstereo_return. The storage returned in
    mono_info_return and stereo_info_return may be released by XFree.  If no
    errors are encounted, non-zero will be returned.

    XmbufCreateStereoWindow creates a stereo window in the same way that
    XCreateWindow creates a mono window. The buffer ids for the left and
    right buffers are returned in left_return and right_return, respectively.
    If an extension error handler that returns is installed, None will be
    returned if the extension is not available on this display.

 Predefined values

    Update_action field:

       MultibufferUpdateActionUndefined
       MultibufferUpdateActionBackground
       MultibufferUpdateActionUntouched
       MultibufferUpdateActionCopied

    Update_hint field:

       MultibufferUpdateHintFrequent
       MultibufferUpdateHintIntermittent
       MultibufferUpdateHintStatic

    Valuemask fields:

       MultibufferWindowUpdateHint
       MultibufferBufferEventMask

    Mono vs. stereo and left vs. right:

       MultibufferModeMono
       MultibufferModeStereo
       MultibufferSideMono
       MultibufferSideLeft
       MultibufferSideRight

    Clobber state:

       MultibufferUnclobbered
       MultibufferPartiallyClobbered
       MultibufferFullyClobbered

    Event stuff:

       MultibufferClobberNotifyMask
       MultibufferUpdateNotifyMask
       MultibufferClobberNotify
       MultibufferUpdateNotify
       MultibufferNumberEvents
       MultibufferBadBuffer
       MultibufferNumberErrors


 See also

    Extending X for Double Buffering, Multi-Buffering, and Stereo
    Xlib - C Language X Interface


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