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XdbeGetVisualInfo(3) X FUNCTIONS XdbeGetVisualInfo(3) NAME XdbeGetVisualInfo - Get dbe Visual Information SYNOPSIS #include <X11/extensions/Xdbe.h> XdbeScreenVisualInfo *XdbeGetVisualInfo( Display *dpy, Drawable *screen_specifiers, int *num_screens) DESCRIPTION This function returns information about which visuals support double buffering. The argument num_screens specifies how many elements there are in the screen_specifiers list. Each drawable in screen_specifiers desig- nates a screen for which the supported visuals are being requested. If num_screens is zero, information for all screens is requested. In this case, upon return from this function, num_screens will be set to the number of screens that were found. If an error occurs, this function returns NULL, else it returns a pointer to a list of XdbeScreenVisualInfo struc- tures of length num_screens. The nth element in the returned list corre- sponds to the nth drawable in the screen_specifiers list, unless num_screens was passed in with the value zero, in which case the nth ele- ment in the returned list corresponds to the nth screen of the server, starting with screen zero. The XdbeScreenVisualInfo structure has the fol- lowing fields: int count XdbeVisualInfo *visinfo count specifies the number of items in visinfo. visinfo specifies a list of visuals, depths, and performance hints for this screen. The XdbeVisualInfo structure has the following fields: VisualID visual int depth int perflevel visual specifies one visual ID that supports double-buffering. depth spec- ifies the depth of the visual. perflevel is a performance hint. The only operation defined on a perflevel is comparison to a perflevel of another visual on the same screen. The visual having the higher perflevel is likely to have better double-buffering graphics performance than the vi- sual having the lower perflevel. Nothing can be deduced from the follow- ing: the magnitude of the difference of two perflevels, a perflevel value in isolation, or comparing perflevels from different servers. ERRORS BadDrawable One or more values passed in screen_specifiers is not a valid draw- able. SEE ALSO DBE, XdbeAllocateBackBufferName(), XdbeBeginIdiom(), XdbeDeallocateBack- BufferName(), XdbeEndIdiom(), XdbeFreeVisualInfo(), XdbeGetBackBufferAt- tributes(), XdbeQueryExtension(), XdbeSwapBuffers(). X Version 11 libXext 1.3.6 XdbeGetVisualInfo(3)
NAME | SYNOPSIS | DESCRIPTION | ERRORS | SEE ALSO
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