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XEVI(3) Library Functions Manual XEVI(3) NAME XeviQueryExtension, XeviQueryVersion, XeviGetVisualInfo - X Extended Visual Information functions SYNOPSIS #include <X11/extensions/XEVI.h> Bool XeviQueryExtension (Display *dpy); Bool XeviQueryVersion (Display *dpy, int *major_version_return, int *minor_version_return); int XeviGetVisualInfo (Display *dpy, VisualID *visual, int n_visual, ExtendedVisualInfo ** evi_return, int * n_info_return); DESCRIPTION The X11 Extended Visual Information extension (EVI) allows a client to determine information about core X visuals beyond what the core proto- col provides. The EVI application programming library contains the interfaces de- scribed below. With the exception of XeviQueryExtension, if any of these routines are called with a display that does not support the ex- tension, the ExtensionErrorHandler (which can be set with XSetExten- sionErrorHandler and functions the same way as XSetErrorHandler) will be called and the function will then return. XeviQueryExtension returns True if the Extended Visual Information ex- tension is available on the given display. A client must call Xevi- QueryExtension before calling any other EVI function in order to nego- tiate a compatible protocol version; otherwise the client will get un- defined behavior (EVI may or may not work). XeviQueryVersion returns True if the request succeeded; the values of the major and minor protocol version supported by the server are re- turned in major_version_return and minor_version_return. XeviGetVisualInfo returns a list of ExtendedVisualInfo structures that describe visual information beyond that supported by the core protocol. This includes layer information relevant for systems supporting over- lays and/or underlay planes, and information that allows applications better to determine the level of hardware support for multiple col- ormaps. XeviGetVisualInfo returns Success if successful, or an X error otherwise. If the argument visual is NULL, then information for all visuals of all screens is returned. Otherwise, it's a pointer to a list of visuals for which extended visual information is desired. n_visual is the number of elements in the array visual. evi_return returns a pointer to a list of ExtendedVisualInfo. When done, the client should free the list using XFree. n_info_return returns the number of ele- ments in the array evi_return. The ExtendedVisualInfo structure has the following fields: VisualID core_visual_id int screen int level unsigned int transparency_type unsigned int transparency_value unsigned int min_hw_colormaps unsigned int max_hw_colormaps unsigned int num_colormap_conflicts VisualID * colormap_conflicts The combination of core_visual_id and screen number uniquely specify the visual being described. level returns the level number for the visual, 0 for normal planes, > 0 for overlays, < 0 for underlays. transparency_type returns the type of transparency supported by the vi- sual. XEVI_TRANSPARENCY_NONE if there are no transparent pixels, XEVI_TRANSPARENCY_PIXEL if the visual supports a transparent pixel, XEVI_TRANSPARENCY_MASK if the visual supports transparent plane(s). transparency_value returns the pixel/plane value to set for trans- parency if transparency_type isn't XEVI_TRANSPARENCY_NONE. min_hw_colormaps and max_hw_colormaps return the minimum and maximum number of hardware colormaps backing up the visual. num_colormap_conflicts returns the number of elements in colormap_con- flicts. This array returns a list of visuals that may cause conflicts in the use of the hardware colormap. For example, if a 12-bit hardware colormap is overloaded to support 8-bit colormaps, the corresponding 8-bit visuals would conflict with the 12-bit visuals. ERRORS XeviGetVisualInfo will return BadValue if passed an illegal visual ID, BadAccess if the X server does not respond, BadAlloc if there is a mem- ory allocation failure. X FUNCTIONS X Version 11 XEVI(3)